JP4776598B2 - Management method, management apparatus, and device manufacturing method - Google Patents

Description

The present invention relates to a management method for managing a manufacturing apparatus used in a manufacturing line for manufacturing an electronic device such as a semiconductor circuit, a management apparatus , and a device manufacturing method using the management method .

  Conventionally, when manufacturing an electronic device such as a semiconductor circuit, the electronic device is manufactured by a plurality of manufacturing processes such as a cleaning process, a heat treatment process, an impurity introduction process, a film forming process, a lithography process, and an etching process. In each manufacturing process, a manufacturing apparatus capable of executing the manufacturing process is used.

  In addition, after the electronic device is manufactured and before the electronic device is shipped, the electronic device is tested to select defective electronic devices. The test is performed by measuring, for example, electrical characteristics of the electronic device.

  In addition, in order to improve the manufacturing yield of electronic devices, defective electronic devices are analyzed and the cause of the failure is detected. For example, it is detected by analyzing an electronic device which process in the production line has a problem.

  However, conventionally, in order to detect which process in the production line has a problem, it is necessary to measure the element shape or the like of a defective electronic device. For example, the cause of failure is estimated from a micrograph of an electronic device. For this reason, it takes time to estimate the cause of the defect. In addition, it is difficult to accurately identify the manufacturing apparatus that has caused the failure.

  Then, an object of this invention is to provide the management method and management apparatus which can solve said subject. This object is achieved by a combination of features described in the independent claims. The dependent claims define further advantageous specific examples of the present invention.

In order to solve the above-described problems, in the first embodiment of the present invention, a management method for managing each manufacturing apparatus used in each manufacturing process for a managed manufacturing line that manufactures an electronic device by a plurality of manufacturing processes. A reference device manufacturing stage for manufacturing a reference device by a predetermined reference manufacturing line capable of executing a plurality of manufacturing processes, a reference characteristic acquisition stage for acquiring characteristics of the reference device, and a plurality of manufacturing processes Of these, the comparative device manufacturing stage in which at least one manufacturing process is processed by the managed manufacturing line, the other manufacturing processes are processed by the reference manufacturing line, and the comparative device is manufactured, and the comparative device is measured. Based on the characteristic comparison stage, which compares the stage, the characteristics of the reference device, and the characteristics of the comparison device There are, and a determining step the quality of the manufacturing apparatus used in the manufacturing process of the managed production line processing the comparison device, reference device manufacturing stage and comparing device fabrication stage, are arranged in a two-dimensional matrix, respectively A test circuit including a plurality of circuits to be measured including a transistor to be measured, and a selection unit that outputs an output signal of one specified circuit to be measured to an output signal line provided in common to the plurality of circuits to be measured The reference device and the comparison device are manufactured by a plurality of manufacturing steps, and the reference characteristic acquisition step includes a transistor selection step in which a selection unit sequentially selects a plurality of circuits to be measured in a test circuit of the reference device. In the test circuit of the reference device, based on the output signal output to the output signal line by the selected circuit under test. And an output measurement stage for measuring the electrical characteristics of the transistor under measurement included in each circuit under test. In the comparison characteristic measurement stage, in the test circuit of the comparison device, a plurality of circuits under test are sequentially selected by the selection unit. In the transistor selection stage to be selected and the test circuit of the comparison device, based on the output signal output from the selected circuit under measurement to the output signal line, the electrical characteristics of the transistor under measurement included in each circuit under measurement are measured. A management method having an output measurement stage is provided.

In the second embodiment of the present invention, a management apparatus that manages each manufacturing apparatus used in each manufacturing process for a managed manufacturing line that manufactures an electronic device by a plurality of manufacturing processes, the plurality of manufacturing processes A reference characteristic measuring unit that measures the characteristics of a reference device manufactured by a predetermined reference manufacturing line, and at least one of the plurality of manufacturing processes is processed by the managed manufacturing line. Other manufacturing processes are processed by the reference manufacturing line, the comparison device manufacturing control unit for manufacturing the comparison device, the comparison characteristic measurement unit for measuring the characteristics of the comparison device, the characteristics of the reference device, and the characteristics of the comparison device Based on the characteristic difference and the characteristic comparison unit that compares the And a judging section that judges acceptability of the manufacturing apparatus using Te, reference production line and comparing device manufacture control unit are arranged in a two-dimensional matrix, a plurality of the circuit under test, each including transistors under measurement, designated A plurality of electronic devices having a test circuit including a selection unit that outputs an output signal of the measured circuit to be output to an output signal line provided in common to the plurality of measured circuits, as a reference device and a comparison device In the reference device test circuit, the reference characteristic measurement unit sequentially selects a plurality of circuits under measurement by the selection unit, based on the output signal output to the output signal line by the selection circuit under test. Measure the electrical characteristics of the transistor under test in each circuit under test, and select the comparison characteristic measurement unit in the test circuit of the comparison device. Sequentially selecting a plurality of the circuit to be measured by, providing a management device based on the output signal which the measuring circuit by the selected output to the output signal line, for measuring the electrical characteristics of the transistors under measurement, each of the measuring circuit has To do.

  According to a third aspect of the present invention, there is provided a device manufacturing method for manufacturing an electronic device using a managed manufacturing line managed by the management method described in the first aspect.

  The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing apparatus used for the manufacturing line which manufactures an electronic device can be managed correctly and easily.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the scope of claims, and all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.

  FIG. 1 is a diagram illustrating an example of a configuration of a management apparatus 10 according to an embodiment of the present invention. The management apparatus 10 manages each manufacturing apparatus used in each manufacturing process for the managed manufacturing line 100 that manufactures an electronic device through a plurality of manufacturing processes. In this example, the management apparatus 10 processes the characteristics of the reference device manufactured by the predetermined reference manufacturing line 200 and the manufacturing process by the manufacturing apparatus to be managed by the managed manufacturing line 100, and uses the other manufacturing processes as a reference. The quality of the manufacturing apparatus is determined by comparing the characteristics of the comparison device manufactured by processing with the manufacturing line 200.

  The managed manufacturing line 100 manufactures an electronic device through a plurality of manufacturing processes. For example, these manufacturing processes are classified into an element isolation process group 110, an element formation process group 114, or a wiring formation process group 118. The managed production line 100 is included in, for example, a device manufacturing system 20 owned by a device manufacturer that supplies electronic devices to the market. The device manufacturing system 20 includes a managed manufacturing line 100, an assembly process group 120, and a test process group 130, and manufactures, assembles, and tests electronic devices.

  The assembly process group 120 cuts out an electronic device from a wafer manufactured by the managed manufacturing line 100 and packages it. The assembly process group 120 includes a scribing process for cutting out each electronic device from the wafer, a die bonding process for attaching the electronic device to the package, a wire bonding process for connecting the chip and the package wiring, and a sealing process for sealing the gas in the package. It may be included and realized by a plurality of assembly devices.

  The test process group 130 performs a current test, a logic test, and the like of an electronic device packaged as a product, and removes defective products. The test process group 130 is realized by one or a plurality of test apparatuses.

  The reference production line 200 can execute the same plurality of production steps as the managed production line 100. For example, the reference manufacturing line 200 includes an element isolation process group 210, an element formation process group 114, and a wiring formation process group 218. In the reference manufacturing line 200, the characteristics of each manufacturing apparatus used in each manufacturing process are measured in advance, and it is guaranteed in advance that each manufacturing apparatus is a non-defective product. The reference production line 200 may be, for example, a production line possessed by a public verification organization, or may be a production line possessed by a device manufacturer. Moreover, the manufacturing line which the verification organization authenticated by the consumer of the electronic device may have.

  The managed production line 100 and the reference production line 200 produce electronic devices through a plurality of production processes. In the present embodiment, these production lines produce wafers on which electronic devices are formed. In addition, these production lines manufacture a wafer having a test circuit including a plurality of transistors to be measured for the purpose of managing the manufacturing quality in each manufacturing process. Here, in these production lines, the electronic device and the test circuit may be formed separately, and the test circuit may be formed inside the electronic device.

  The management apparatus 10 includes a reference characteristic measurement unit 140, a comparison characteristic measurement unit 142, a characteristic comparison unit 150, a determination unit 160, and a comparison device manufacturing control unit 170. The reference characteristic measurement unit 140 acquires the characteristics of a reference device manufactured by processing all the processes using the reference manufacturing line. The reference characteristic measurement unit 140 may measure the electric characteristics of the reference device, for example.

  The comparison device manufacturing control unit 170 causes at least one manufacturing process among the plurality of manufacturing processes for manufacturing the electronic device to be processed by the managed manufacturing line 100 and the other manufacturing processes to be processed by the reference manufacturing line 200. Manufacturing. For example, in the managed production line 100 and the reference production line 200, the comparison device production control unit 170 designates a production process for processing the comparison device. Further, the comparison device manufacturing control unit 170 may perform control to cause the manufacturing device that performs the manufacturing process to transport the comparison device and operate the manufacturing device. The comparison device manufacturing control unit 170 may be provided for each of the reference manufacturing line 200 and the managed manufacturing line 100. Further, the comparison device manufacturing control unit 170 may include means for transporting an electronic device in the manufacturing process between the managed manufacturing line 100 and the reference manufacturing line 200.

  The comparison characteristic measurement unit 142 measures the characteristic of the comparison device. The reference characteristic measurement unit 140 measures the characteristics of each device with respect to the same measurement item as the reference device characteristic acquired by the reference characteristic measurement unit 140. For example, the reference characteristic measurement unit 140 and the comparison characteristic measurement unit 142 acquire the same electrical characteristics for TEG (Test Element Group) provided in each device.

  The item of the device characteristic to be acquired by the reference characteristic measurement unit 140 and the comparison characteristic measurement unit 142 may be determined in advance, and the reference characteristic measurement unit 140 may notify the comparison characteristic measurement unit 142 of the item to be acquired. Further, the comparison characteristic measurement unit 142 may notify the reference characteristic measurement unit 140 of items to be acquired.

  The characteristic comparison unit 150 compares the characteristic of the reference device acquired by the reference characteristic measurement unit 140 with the characteristic of the comparison device measured by the comparison characteristic measurement unit 142. The determination unit 160 determines the quality of the manufacturing apparatus used in the manufacturing process of the managed manufacturing line 100 that has processed the comparison device, based on the difference in characteristics compared by the characteristic comparison unit 150. For example, the determination unit 160 determines that the manufacturing apparatus is a non-defective product when the characteristic difference is within a predetermined range, and when the characteristic difference is outside the predetermined range, The manufacturing apparatus may be determined as a defective product. The determination unit 160 preferably notifies the user of the managed production line 100 of the determination result.

  With such a configuration, the quality of the manufacturing apparatus can be accurately determined. In addition, since the electrical characteristics of the devices should be compared, the quality of the manufacturing apparatus can be easily determined.

  FIG. 2 is a diagram illustrating an example of the configuration of the managed production line 100. In this example, the configuration of the managed production line 100 is shown, but the reference production line 200 also has the same configuration. As described above, the managed production line 100 includes the plurality of manufacturing apparatuses 105 in each of the element isolation process group 110, the element formation process group 114, and the wiring formation process group 118. Each manufacturing apparatus 105 executes a corresponding manufacturing process.

  Each manufacturing apparatus 105 performs a predetermined process on a given wafer and conveys the wafer to the subsequent manufacturing apparatus 105. By sequentially performing processing in each manufacturing apparatus 105, an electronic device is formed on the wafer. Further, when manufacturing a comparison device, each manufacturing apparatus 105 processes a wafer independently in accordance with control from the comparison device manufacturing control unit 170. In accordance with control from the comparison device manufacturing control unit 170, a wafer on which the comparison device is to be formed is carried into the manufacturing apparatus 105 that operates to manufacture the comparison device from the reference manufacturing line 200. Further, the wafer processed by the manufacturing apparatus 105 is carried out to the reference manufacturing line 200 in accordance with control from the comparison device manufacturing control unit 170.

  Under such control, a comparison device that selects a manufacturing apparatus 105 to be managed in the managed production line 100, processes a corresponding manufacturing process in the managed manufacturing line 100, and processes other manufacturing processes in the reference manufacturing line 200. Can be manufactured.

  The element isolation process group 110, the element formation process group 114, and the wiring formation process group 118 may each perform the following processing. The element isolation process group 110 (isolation process group) electrically isolates regions in which elements such as transistors are arranged on a substrate (wafer) by one or a plurality of manufacturing apparatuses 105. The element formation process group 114 forms each element on the wafer by one or a plurality of manufacturing apparatuses 105.

  The element isolation process group 110 and the element formation process group 114 are also referred to as a substrate process for forming an element such as a transistor on a substrate, and are also referred to as a previous process (FEOL: Front End Of the Line). The wiring formation process group 118 forms wiring for connecting between elements formed on the wafer or between elements and terminals by one or a plurality of manufacturing apparatuses 105. The wiring formation process group 118 is also referred to as a wiring process in which wiring is formed on a substrate on which elements are formed, and is also referred to as a post-process (BEOL: Back End Of the Line).

  The element isolation process group 110, the element formation process group 114, and the wiring formation process group 118, for example, produce a result of each process group by combining one or more of the following processes. Here, the 1 or 2 or more manufacturing apparatus 105 processes the following each process. Instead, one manufacturing apparatus 105 may process a plurality of the following steps.

(1) Cleaning step In this step, the substrate surface is cleaned by removing particles or metal contamination on the substrate surface. Wet cleaning or dry cleaning is used.
(2) Thermal process
This is a step of heating the wafer. There are a thermal oxidation process for the purpose of forming a thermal oxide film, an annealing process for activation after ion implantation, and the like.

(3) Impurity introduction step Impurities are introduced onto the substrate. For example, an impurity such as boron (B) or phosphorus (P) is introduced into a semiconductor substrate such as a silicon substrate by ion implantation or the like to form a pn junction.
(4) Film formation process (thin film formation process)
A thin film such as a Si oxide film, a Si nitride film, a polysilicon film, or a Cu film is deposited on the substrate by CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), coating / coating, electroplating, or the like.

(5) Lithography step A photoresist is applied on the substrate, the pattern is exposed with a mask, and then the photoresist is developed.
(6) Etching Step After the photoresist is removed by development in the lower layer film of the photoresist, the exposed portion is removed by etching, and then the photoresist is removed. A plasma etching method, a reactive ion etching (RIE) method, or the like is used.
(7) Planarization process The substrate surface is ground and planarized. A CMP (Chemical and Mechanical Polishing) method or the like is used.

  For example, a DRAM (Dynamic RAM) is manufactured through 500 to 600 processes as an example. Moreover, CMOS-LSI is manufactured through 300-400 processes as an example. The comparison device manufacturing control unit 170 may select one of the manufacturing processes described above and operate the manufacturing apparatus 105 corresponding to the manufacturing process in the managed manufacturing line 100.

  FIG. 3 is a flowchart illustrating an example of the operation of the management apparatus 10. First, in the reference characteristic step S600, the reference characteristic measurement unit 140 acquires the characteristics of the reference device. Next, in the comparative device manufacturing stage S602, the comparative device manufacturing control unit 170 causes a part of the manufacturing process to be judged as to whether the corresponding manufacturing apparatus is good or not to be processed in the managed manufacturing line 100, and the other manufacturing processes are based on the standard manufacturing. A comparative device processed in line 200 is manufactured.

  Next, in the comparison characteristic measurement step S604, the comparison characteristic measurement unit 142 measures the characteristics of the comparison device. Next, in the characteristic comparison step S606, the characteristic comparison unit 150 compares the characteristic of the reference device with the characteristic of the comparison device.

  In the determination step S608, the determination unit 160 determines the quality of the manufacturing apparatus used in the managed manufacturing line 100 based on the comparison result. By such processing, it is possible to determine whether the manufacturing apparatus is good or bad. In addition, the device manufacturer may manufacture the electronic device using a manufacturing line managed by the management method described with reference to FIG.

  FIG. 4 is a chart showing an example of processing when a device manufacturer has a managed production line 100 and a reference production line 200 has an external verification organization. In this case, the verification organization may have the management device 10.

  First, the verification organization measures in advance the characteristics of the plurality of manufacturing apparatuses 105 used in the reference manufacturing line 200 (S610). Then, it is guaranteed in advance that each manufacturing apparatus 105 is a non-defective product (S612). In S610 and S612, the verification organization measures the electrical characteristics of the electronic device manufactured by the reference manufacturing line 200, and when the electrical characteristics of the electronic device are within a predetermined allowable range, each manufacturing apparatus It may be guaranteed that 105 is a non-defective product. In addition, the verification organization causes each manufacturing apparatus 105 to process a predetermined wafer, and the difference between the characteristics of the wafer before the processing and the characteristics of the wafer after the processing is within a predetermined expected range. The manufacturing apparatus 105 may be guaranteed to be a non-defective product. In addition, the verification organization may process a plurality of wafers in S610 and guarantee that each manufacturing apparatus 105 is a non-defective product when the characteristics of all the wafers are within a predetermined allowable range.

  Next, the device manufacturer constructs a managed production line 100 that manufactures electronic devices to be shipped to the market (S614). The device manufacturer notifies the verification organization of information on each manufacturing apparatus 105 included in the constructed managed production line 100 (S616).

  The verification organization acquires information on the manufacturing apparatus 105 used for the managed manufacturing line 100 (S616), and builds the same reference manufacturing line 200 as the managed manufacturing line 100 based on the information (S620). At this time, the verification organization constructs the reference production line 200 using the production apparatus 105 that is guaranteed to be non-defective in S612. In another example, the verification organization may perform the processes of S610 and S612 on the manufacturing apparatus 105 that constructs the reference production line 200 after constructing the reference production line 200.

  The verification organization manufactures the reference device by using the established reference manufacturing line 200 (S620). The verification organization measures the characteristics of the manufactured reference device (S622). Then, the device manufacturer selects the manufacturing apparatus 105 that determines pass / fail in the managed manufacturing line 100, and notifies the verification organization (S624).

  The verification organization processes the wafer by the reference manufacturing line 200 until the previous process of the manufacturing process corresponding to the notified manufacturing apparatus 105, and generates an intermediate product of the comparison device (S626). Then, the verification organization transports the wafer processed in S626 to the device manufacturer (S628).

  The device manufacturer processes the received wafer by the manufacturing apparatus 105 of the managed manufacturing line 100 (S630). Then, the device manufacturer transports the wafer processed by the manufacturing apparatus 105 to the verification organization (S632).

  The verification organization processes the received wafer with the reference manufacturing line 200 for the remaining manufacturing steps, and manufactures a comparison device (S634). Then, the characteristics of the comparison device are measured (S636), and the quality of the manufacturing apparatus 105 is determined by comparing with the characteristics of the reference device (S638). Then, the verification organization notifies the determination result of the manufacturing apparatus 105 to the device manufacturer. By such processing, the device manufacturer is assured of the quality of the manufacturing apparatus 105 by an external organization.

  FIG. 5 is a flowchart showing an example of processing in a case where one of the plurality of manufacturing lines owned by the device manufacturer functions as the reference manufacturing line 200 and the other manufacturing line functions as the managed manufacturing line 100. It is. In this example, a plurality of production lines owned by a device manufacturer produce electronic devices by the same production process.

  First, an electronic device is manufactured by each manufacturing line, and the characteristics of the manufactured electronic device are measured (S642). Next, the reference production line 200 is selected from a plurality of production lines based on the measured characteristics of the electronic device (S644). For example, a manufacturing line whose characteristics of the manufactured electronic device are closest to a predetermined reference value is selected as the reference manufacturing line 200. At this time, a plurality of electronic devices may be manufactured in each manufacturing line, the average value of the characteristics of the electronic device may be calculated for each manufacturing line, and the manufacturing line whose average value is closest to the reference value may be selected. .

  Then, the other production lines not selected as the reference production line 200 among the plurality of production lines are managed as the managed production line 100 (S646). The management in S646 may be performed on each production line by the processing shown in FIG. 3, for example.

  FIG. 6 shows an example of a top view of a wafer 500 on which a plurality of electronic devices 510 are formed by the managed production line 100 or the reference production line 200. The managed manufacturing line 100 may manufacture a wafer 500 having a plurality of test circuits 300 each including a plurality of transistors to be measured and a plurality of electronic devices 510 for the purpose of line management or yield management. The electronic device 510 is a device for a product to be shipped as an actual operation device.

  The test circuit 300 may be provided for each boundary between the electronic devices 510. In this case, the plurality of test circuits 300 may be provided in a dicing region that is cut when the plurality of electronic devices 510 is diced between the electronic devices 510. Instead, the test circuit 300 may be provided inside the electronic device 510. In the case of a wafer used for line management, only a plurality of test circuits 300 may be formed on the surface of the wafer 500. The reference characteristic measurement unit 140 and the comparison characteristic measurement unit 142 may measure electrical characteristics of the test circuit 300 formed corresponding to the reference device or the comparison device.

  In the reference characteristic acquisition step S600 and the comparative device manufacturing step S602 described with reference to FIG. 3, an electronic device or wafer having a test circuit described with reference to FIG. 7 or FIG. 11 is manufactured through a plurality of manufacturing processes.

  FIG. 7 shows an example of the circuit configuration of the test circuit 300. The test circuit 300 can efficiently measure the electrical characteristics of each of a large number of transistors under measurement 314. Thereby, the reference characteristic measuring unit 140 and the comparative characteristic measuring unit 142 can sufficiently obtain the number of samples of the transistor under measurement for measuring the electrical characteristics. As a result, the reference characteristic measurement unit 140 and the comparison characteristic measurement unit 142 can accurately compare the characteristics of the reference device and the comparison device.

  The test circuit 300 includes a column selection unit 302, a row selection unit 304, a plurality of column selection transistors (306-1, 306-2, hereinafter collectively referred to as 306), and a plurality of current sources (318-1, 318-2, hereinafter). 318), an output unit 320, and a plurality of cells (310-1 to 310-4, hereinafter collectively referred to as 310). The column selection transistor 306 is provided corresponding to each column of the plurality of cells 310, and a plurality of current sources (318 −) that supply a specified source-drain current to the cells 310 to which a selection signal is input by the row selection unit 304. 1-2) is further included.

  The plurality of cells 310 are an example of a circuit under measurement according to the present invention, and are arranged in a two-dimensional matrix form in the plane of the wafer 500. The plurality of cells 310 are provided in parallel along the row direction and the column direction of the two-dimensional matrix. In this example, a circuit in which two cells 310 are provided in the row direction and the column direction is shown, but a larger number of cells 310 can be provided in the row direction and the column direction. Further, the plurality of cells 310 are provided over a plurality of divided regions. For example, each divided region has cells 310 of 128 columns in the row direction and 512 rows in the column direction. In this case, the process rules and device sizes of elements included in the cell 310 may be different for each divided region.

  Each cell 310 includes a transistor under measurement 314, a switching transistor 312, and a row selection transistor 316. The transistor of each cell 310 may be a MOS transistor formed by the same process as the actual operation transistor included in the electronic device 510.

  The transistors under measurement 314 of each cell 310 are provided electrically in parallel with each other. The case where the transistor under measurement 314 according to this embodiment is an NMOS transistor will be described as an example. Alternatively, the transistor under measurement 314 may be a PMOS transistor, and in this case, a circuit in which the source and drain are interchanged may be used.

A predetermined reference voltage V _DD is input to one reference voltage side terminal of the drain terminal and the source terminal of each transistor under measurement 314. The wiring for supplying the reference voltage input from the outside to each cell 310 to the reference voltage side terminal of the transistor under measurement functions as a reference voltage input unit according to the present invention. Here, the reference voltage side terminal may be a drain terminal when the transistor under measurement 314 is an NMOS transistor, and may be a source terminal when it is a PMOS transistor. The well voltage terminal of the transistor under measurement 314 is not shown, but the well voltage terminal may be connected to the ground potential, and the well voltage can be controlled independently for each transistor, so The voltage terminal and the source terminal may be connected. The reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 illustrated in FIG. 1 may supply the voltage V _DD , the voltage V _G , the voltage φ _j , and the voltage V _REF illustrated in FIG. 7 to the test circuit 300.

The switching transistor 312 of each cell 310 is provided corresponding to the transistor under measurement 314 of each cell. Each switching transistor 312 functions as a gate voltage control unit that applies the gate voltage specified by the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 to the gate terminal of the corresponding transistor under measurement 314. In this example, when the switching transistor 312 is an NMOS transistor, the drain terminal of the switching transistor 312 is given voltage V _G of predetermined voltage to the gate terminal controls the operation of the switching transistor 312 phi _j And the source terminal is connected to the gate terminal of the transistor under measurement 314. That is, when the switching transistor 312 is controlled to be turned on by the voltage φ _j , a voltage substantially equal to the voltage V _G is applied to the gate terminal of the transistor 314 to be measured, and when the switching transistor 312 is controlled to be turned off, the initial voltage is the voltage of the floating state of the substantially V _G applied to the gate terminal of the transistor under measurement 314.

FIG. 7 shows an example in which the voltage φ _j is applied to all the cells 310 at once. However, in another example, the voltage φ _j is selected as a row so that the leak time when measuring the PN junction leakage current is the same for all cells. A pulse signal may be sequentially applied from the unit 304 to the cells 310 arranged in the column direction.

  The row selection transistor 316 of each cell 310 is provided corresponding to the transistor under measurement of each cell. Each row selection transistor 316 outputs, as an output signal, a terminal voltage of a terminal other than the reference voltage side terminal among the drain terminal and the source terminal of the transistor under measurement 314 on condition that a selection signal is input from the outside of the cell 310. Functions as a terminal voltage output unit. In this example, when the row selection transistor 316 is a PMOS transistor, the source terminal of each row selection transistor 316 is connected to the drain terminal of the transistor under measurement 314. The drain terminal of the row selection transistor 316 is connected to the drain terminal of the corresponding column selection transistor 306. That is, the drain terminal of each column selection transistor 306 is connected to the drain terminals of the corresponding plurality of row selection transistors 316.

  The row selection unit 304 outputs a selection signal to the cell 310 corresponding to the designated row among the plurality of cells 310 arranged in a two-dimensional matrix. As a result, the row selection unit 304 includes a plurality of cells 310 provided along the column direction (in this example, the cell groups (310-1, 310-2) and the cell groups (310-3, 310-4)). ) In order. In addition, the column selection unit 302 selects the terminal voltage of the cell 310 corresponding to the designated column among the two or more cells 310 located in the row to which the selection signal is input, and outputs the selected terminal voltage to the output signal line. Thereby, the column selection unit 302 includes a plurality of cells 310 groups (in this example, cell groups (310-1, 310-3) and cell groups (310-2, 310-4)) provided along the row direction. ) In order. With such a configuration, the row selection unit 304 and the column selection unit 302 can sequentially select each cell 310.

  In this example, the row selection unit 304 sequentially selects the row selection transistors 316 provided in the cell groups of the respective columns for each row position corresponding to the row selection data given from the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142. Control to ON state. Further, the column selection unit 302 includes a column selection transistor 306 provided corresponding to the cell group in each row direction for each column position corresponding to the column selection data given from the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142. Control to turn on sequentially. Thus, the column selection unit 302 and the row selection unit 304 function as a selection unit according to the present invention, and the output signal of one cell 310 specified by the measurement control unit 146 is provided in common to the plurality of cells 310. The output signal line connecting each column selection transistor 306 and the output unit 320 and the output unit 320 can output the signal.

  The reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 supplies a selection signal for sequentially selecting each cell 310 to the row selection unit 304 and the column selection unit 302. In addition, the column selection unit 302 and the row selection unit 304 may include circuits such as a decoder and a shift register that convert given column selection data and row selection data into a selection signal corresponding to the position of the cell 310 to be selected. . Here, the selection signal is a signal for controlling the column selection transistor 306 and the row selection transistor 316 corresponding to the cell 310 to be selected according to the selection data to be in an ON state.

  With such a configuration, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 sequentially selects the transistor under measurement 314 provided in each cell 310. As a result, the terminal voltage of the transistors under measurement 314 that are sequentially selected can be sequentially output to the output unit 320. The output unit 320 sequentially outputs the terminal voltage to the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142. The output unit 320 may be a voltage follower buffer, for example. Based on the terminal voltage of each measured transistor 314, the reference characteristic measuring unit 140 or the comparison characteristic measuring unit 142 determines the threshold voltage, current voltage characteristics, low frequency noise, PN junction leakage current, etc. of the measured transistor 314. Measure electrical characteristics.

Each current source 318 is a MOS transistor that receives a predetermined voltage _VREF at its gate terminal. The drain terminal of each current source 318 is connected to the drain terminals of the corresponding plurality of row selection transistors 316. That is, each current source 318 is provided in common to a plurality of transistors under measurement 314 provided at the same column position, and defines a source-drain current flowing through the corresponding transistor under measurement 314.

  According to the circuit configuration shown in FIG. 7, in each test circuit 300, a plurality of transistors under measurement 314 can be electrically sequentially selected, and terminal voltages of the selected transistors under measurement 314 can be sequentially output. The terminal voltage of each transistor under measurement 314 can be measured at high speed in a short time. Therefore, even when a large number of transistors to be measured 314 are provided on the wafer 500, all the transistors to be measured 314 can be measured in a short time.

  Therefore, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 can efficiently and accurately measure the electrical characteristics of the reference device or the comparison device. In this example, about 10,000 to 10 million transistors to be measured 314 may be provided in the plane of the wafer 500. By measuring a large number of transistors under measurement 314, variation in characteristics of the transistors under measurement 314 can be calculated with high accuracy.

  FIG. 8 is a flowchart showing an example of the operation of the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 when measuring variations in threshold voltages of the transistors under measurement 314 as the characteristics of the reference device and the comparison device. It is.

First, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 supplies the test circuit 300 with the voltage V _DD , the voltage V _G , the voltage φ _j , and the voltage V _REF described in FIG. 7 (S440). At this time, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 functions as a current control unit that supplies a constant voltage V _REF to each current source 318 and causes each current source 318 to generate the same constant current. Further, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 supplies a gate voltage V _G for controlling the transistor under measurement 314 to be turned on, and supplies a voltage φ _j for controlling each of the switching transistors 312 to be turned on. To do. By such control, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 serves as a gate control unit that applies a gate voltage that controls the transistor under measurement 314 to the on state to the gate terminal of each transistor under measurement 314. Function.

  Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 supplies selection data for selecting the transistor under measurement 314 whose threshold voltage is to be measured to the column selection unit 302 and the row selection unit 304 (S442). . Accordingly, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 causes the column selection unit 302 and the row selection unit 304 to sequentially select the plurality of cells 310. Then, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 measures the output voltage of the output unit 320 (S444). As a result, the reference characteristic measuring unit 140 or the comparison characteristic measuring unit 142 measures the electrical characteristics of the measured transistor 314 included in each cell 310 based on the output signal output from the selected cell 310 to the output signal line. can do.

Next, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 determines the threshold of each measured transistor 314 based on the gate voltage V _G applied to the measured transistor 314 and the output voltage of the output unit 320. A value voltage is calculated (S446). The threshold voltage of the transistor under measurement 314, for example, the difference between the output voltage gate voltage V _G, can be words obtained by calculating the gate-source voltage of the transistor under measurement 314.

  Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 determines whether or not the threshold voltage has been measured for all the transistors under measurement 314 (S448), and the transistors under measurement 314 that have not been measured yet are determined. If there is, the next transistor under measurement 314 is selected, and the processing of S444 and S446 is repeated. When the threshold voltage is measured for all the transistors under measurement 314, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 calculates the variation in the threshold voltage (S450).

  By such an operation, variations in threshold voltages of the plurality of transistors under measurement 314 can be efficiently measured. In addition, the threshold voltage variation of the transistor under measurement 314 can be measured for each process rule. Further, by performing measurement on a plurality of test circuits 300 provided on the wafer 500, the distribution of threshold voltage variations on the surface of the wafer 500 can be measured.

  FIG. 9 is a flowchart showing an example of the operation of the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 when measuring variations in the current-voltage characteristics of the respective transistors under measurement 314 as the characteristics of the reference device and the comparison device. is there.

First, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 supplies the voltage V _DD , the voltage V _G , the voltage φ _j , and the voltage V _REF described in FIG. 7 to the test circuit 300 (S400). At this time, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 supplies a constant voltage V _REF to each current source 318 and causes each current source 318 to generate the same constant current. Further, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 supplies a gate voltage V _G for controlling the transistor under measurement 314 to be turned on, and supplies a voltage φ _j for controlling each of the switching transistors 312 to be turned on. To do.

Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 supplies selection data for selecting the transistor under measurement 314 whose current-voltage characteristics are to be measured to the column selection unit 302 and the row selection unit 304 (S402). Then, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 changes V _REF with a predetermined resolution within a predetermined range (S406 to S408). At this time, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 measures the output voltage of the output unit 320 for each V _REF (S404). That is, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 sequentially changes the source-drain current generated by the current source 318, and measures the source voltage of the transistor under measurement 314 for each source-drain current. Thereby, the current-voltage characteristic of the transistor under measurement 314 can be measured.

  Then, it is determined whether or not the current-voltage characteristics have been measured for all the transistors under measurement 314 (S410). If there is a measured transistor 314 that has not been measured, the processes of S400 to S410 are repeated. At this time, the next transistor under measurement 314 is selected in S402.

  When the current-voltage characteristics are measured for all the transistors under measurement 314, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 calculates the variation in the current-voltage characteristics (S412). For example, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 calculates the mutual conductance gm of each current-voltage characteristic and calculates the variation of the mutual conductance gm. Further, the inclination swing and the silicon gate insulating film interface state density are calculated from the current-voltage characteristics of the subthreshold region, and the variation is calculated.

  FIG. 10 is a flowchart illustrating an example of the operation of the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 when measuring variations in the PN junction leakage current of each transistor under measurement 314 as the characteristics of the reference device and the comparison device. It is.

  Each switching transistor 312 has a PN junction connected to the gate terminal of the corresponding transistor under measurement 314. In this example, the leakage current at the PN junction is measured.

First, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 supplies the voltage V _DD , the voltage V _G , the voltage φ _j , and the voltage V _REF described in FIG. 7 to the test circuit 300 (S460). At this time, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 supplies a constant voltage V _REF to each current source 318 and causes each current source 318 to generate the same constant current. Further, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 supplies a gate voltage V _G for controlling the transistor under measurement 314 to be turned on, and supplies a voltage φ _j for controlling each of the switching transistors 312 to be turned on. To do. Further, by sequentially supplying pulse signals from the row selection unit 304 to the cells 310 arranged in the row direction, the leak current measurement time of all the cells can be made the same.

  Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 supplies selection data for selecting the measured transistor 314 whose PN leakage current is to be measured to the column selection unit 302 and the row selection unit 304 (S462). Then, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 controls the switching transistor 312 corresponding to the selected transistor under measurement 314 to be in an OFF state (S464). That is, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 has, for each switching transistor 312, a gate voltage that turns on the corresponding transistor under measurement 314 and a gate voltage that turns off the transistor under measurement 314. Are sequentially applied to the transistor under measurement 314.

  Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 determines the source voltage when the transistor under measurement 314 is turned on and the source after a predetermined time has elapsed since switching from the on state to the off state. The voltage is measured (S466). In this example, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 measures a change in the output voltage of the output unit 320 during the predetermined time.

  Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 calculates a leakage current in the PN junction based on the change in the source voltage (S468). When the switching transistor 312 is in an on state, a charge corresponding to the gate voltage is accumulated in the gate capacitance of the transistor under measurement 314. When the switching transistor 312 is switched to the off state, the charge of the gate capacitance is discharged by the leak current at the PN junction. For this reason, the magnitude of the PN junction leakage current is determined by the amount of change in the source voltage of the transistor under measurement 314 in a predetermined time.

  Next, it is determined whether or not the PN junction leakage current has been measured for all the transistors under measurement 314 (S470). If there is a transistor under measurement 314 that has not been measured, the processing of S462 to S470 is repeated. At this time, the next transistor under measurement 314 is selected in S462. When the PN junction leakage current is measured for all the transistors under measurement 314, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 calculates the variation of the PN junction leakage current (S472).

  FIG. 11 shows another example of the circuit configuration of each cell 310 included in the test circuit 300. The circuit in this example fills the capacitor 388 with the gate leakage current of the transistor under measurement 372 in the state where an electrical stress is applied to the transistor under measurement 372 and a constant electric field is applied to the gate insulating film of the transistor under measurement 372. Discharge. Then, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 calculates the gate leakage current of each transistor under measurement 372 based on the change in the voltage value of the capacitor 388 at a predetermined time.

  The circuit configuration of the test circuit 300 in this example is different from the circuit configuration of the test circuit 300 shown in FIG. FIG. 11 shows the configuration of each cell 310 of the test circuit 300, including a column selection unit 302, a row selection unit 304, a plurality of column selection transistors (306-1, 306-2, hereinafter collectively referred to as 306), a plurality of The current sources (318-1, 318-2, hereinafter collectively referred to as 318) and the output unit 320 are the same as those in FIG.

  Each cell 310 includes a stress application unit 394, a measured transistor 372, a gate voltage control unit 371, a first switch 374, a second switch 376, a voltage application unit 382, a capacitor 388, a row selection transistor 392, and a reset transistor 378. 380 and an output transistor 390.

  The stress application unit 394 applies electrical stress to the gate insulating film of the transistor under measurement 372 via the first switch 374. For example, when the transistor under measurement 372 is used as a memory element of a FLASH memory, the stress applying unit 394 applies a voltage required for writing data to the transistor under measurement 372 and erasing data.

  When the stress applying unit 394 applies stress, the stress applying unit 394 turns on the first switch 374 and connects the source terminal and the drain terminal of the transistor under measurement 372 to the stress applying unit 394, respectively. In addition, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 turns the second switch 376 off. Through such control, the stress applying unit 394 can apply a desired voltage to each terminal of the transistor under measurement 372 and apply stress.

In this example, the stress application unit 394 applies the following four types of stress to the transistor under measurement 314 independently or sequentially.
(1) FN (Fowler-Nordheim) Gate injection
(2) FN Substrate injection
(3) Hot Electron injection
(4) Source Erase

  The above (1) to (4) are methods in which stress is applied to the transistor under measurement 372 by writing data to the transistor under measurement 372 or erasing the data of the transistor under measurement 372. Here, the stress applying unit 394 applies a voltage to be applied to each terminal of the transistor under measurement 372 when writing data to the transistor under measurement 372 or erasing data of the transistor under measurement 372 during actual operation. Alternatively, a voltage larger than the voltage to be applied during actual operation may be applied to each terminal of the transistor 372 to be measured.

Each cell 310 is _{supplied with} a reset signal φ _RES , control voltages V _RN , V _RP , V _R1 , V _R2 , V _DD , and a gate voltage V _G from the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142. It is done. The gate voltage control unit 371 applies the gate voltage V _G specified by the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 to the gate terminal of the transistor under measurement 372.

  The second switch 376 switches whether the source terminal and the drain terminal of the transistor under measurement 372 are connected to the capacitor 388 via the voltage application unit 382. The voltage application unit 382 applies a constant voltage to the source terminal and the drain terminal of the transistor under measurement 372 via the second switch 376. When the second switch 376 is turned on by the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142, the voltage generated by the voltage application unit 382 is applied to the source terminal and the drain terminal of the transistor 372 to be measured. That is, the voltage application unit 382 controls the electric field applied to the gate insulating film of the transistor under measurement 372 to be substantially constant by applying a constant voltage to the source terminal and the drain terminal of the transistor under measurement 372.

The voltage application unit 382 includes an NMOS transistor 384 and a PMOS transistor 386. The NMOS transistor 384 is supplied with a gate voltage V _RN corresponding to the voltage to be applied to the source terminal and drain terminal of the transistor under measurement 372, and the source terminal is connected to the source terminal of the transistor under measurement 372 via the second switch 376. The drain terminal is connected to the capacitor 388. The PMOS transistor 386 is provided in parallel with the NMOS transistor 384, is supplied with the gate voltage _VRP corresponding to the voltage to be applied to the source terminal and the drain terminal of the transistor under measurement 372, and the drain terminal is the second switch 376. Are connected to the source terminal and drain terminal of the transistor 372 to be measured, and the source terminal is connected to the capacitor 388. The NMOS transistor 384 and the PMOS transistor 386 keep the voltage applied between the gate and the source or the gate and the drain of the transistor 372 to be measured even when the gate leak current is integrated into the capacitor 388 and the potential changes.

  With such a configuration, a constant electric field can be applied to the gate insulating film of the transistor 372 to be measured regardless of whether the transistor 372 to be measured is P-type or N-type. The capacitor 388 can be charged / discharged by the current.

The capacitor 388 is charged and discharged by the gate leakage current output from the source terminal and the drain terminal of the transistor under measurement 372. That is, the capacitor 388 accumulates the gate leakage current flowing from the gate terminal to the source terminal and the drain terminal, and converts it into a voltage value. The reset transistor 378 and 380, when receiving a reset signal phi _RES to the gate terminal, initializing the voltage value at the capacitor 388 to a predetermined voltage _{V R1.}

  The output transistor 390 receives the voltage in the capacitor 388 at the gate terminal, and outputs a source voltage corresponding to the voltage. The row selection transistor 392 outputs the source voltage of the output transistor 390 to the column selection transistor 306 on condition that the selection signal from the row selection unit 304 is input. Thus, the output transistor 390 and the row selection transistor 392 can function as a capacitor voltage output unit that outputs the capacitor voltage at the end of the capacitor 388 on the source terminal and drain terminal side as an output signal.

  FIG. 12 shows an example of the operation of the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 when measuring the gate leakage current of each transistor under measurement 372 as the characteristics of the reference device and the comparison device. Before measuring the gate leakage current of each measured transistor 372, first, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 applies an electrical stress to the measured transistor 372 of each cell 310.

  At this time, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 controls the first switch 374 to be in an on state and controls the second switch 376 to be in an off state. Then, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 controls the stress applying unit 394 of each cell 310 to apply the stress to the measured transistor 372. Further, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 may apply the stresses (1) to (4) described in FIG. 10 to the transistor 372 to be measured independently or sequentially. The reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 applies stress to the measured transistors 372 of each cell 310 substantially simultaneously.

  After performing the above operation, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 sequentially selects each measured transistor 372 and measures the gate leakage current of the selected measured transistor 372. Since the selection operation 372 is the same as the selection operation described in FIGS. 8 and 9, the description thereof is omitted. In this example, an operation for measuring the gate leakage current of one transistor under measurement 372 will be described.

  First, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 controls the first switch 374 to be in an off state and controls the second switch 376 to be in an on state. Then, the reference characteristic measuring unit 140 or the comparative characteristic measuring unit 142 applies a gate voltage of approximately 0 V to the gate terminal of the transistor under measurement 372 (S416). At this time, no gate leakage current is generated in the transistor under measurement 372.

Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 sets the voltage of the capacitor 388 to a predetermined initial voltage value. At this time, the reference property measuring section 140 or the comparison property measuring section 142 controls the reset transistor 380, an initial voltage _{V R1} to the capacitor 388. This setting is performed by supplying a reset signal φ _RES that controls the reset transistors 378 and 380 to be turned on.

  Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 sets the voltage of the capacitor 388 to the initial voltage value, and then reads the change in the voltage value of the capacitor 388 for a predetermined time (S418). At this time, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 causes the column selection unit 302 and the row selection unit 304 to select the cell 310. Further, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 receives the voltage output from the output unit 320 as the voltage of the capacitor 388.

  Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 determines the current value (first current) of the background current of the cell 310 based on the change amount of the voltage output by the output unit 320 during the predetermined period. Value) is calculated (S420). At this time, since no gate leakage current is generated in the transistor under measurement 372, the capacitor 388 is charged and discharged by the background current. Therefore, the background current can be measured based on the voltage change of the capacitor 388 in a predetermined period.

Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 applies a positive or negative gate voltage to the gate terminal of the transistor under measurement 372 (S422). At this time, the voltages V _RN and V _RP are controlled to keep the voltage applied between the gate and source of the transistor under measurement 372 or the gate and drain substantially constant. At this time, a gate leakage current corresponding to the gate voltage is generated in the transistor under measurement 372.

  Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 sets the voltage of the capacitor 388 to a predetermined initial voltage value. Then, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 sets the voltage of the capacitor 388 to the initial voltage value, and then reads the change in the voltage value of the capacitor 388 during the predetermined period described above (S424).

  Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 generates the second current indicating the sum of the background current and the gate leakage current based on the amount of change in the voltage value of the capacitor 388 in the predetermined period. A value is calculated (S426). At this time, the capacitor 388 is charged / discharged by the sum of the background current and the gate leakage current. Therefore, the sum of the background current and the gate leakage current can be measured based on the voltage change of the capacitor 388 in a predetermined period.

  Next, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 calculates the current value of the gate leakage current by subtracting the first current value from the calculated second current value (S428).

  As described above, the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 measures the voltage of the capacitor 388 through the output transistor 390 and the row selection transistor 392 as the electrical characteristics of the respective transistors under measurement 372. be able to. As a result, by the control described above, the influence of the background current can be eliminated, and the gate leakage current of the transistor under measurement 372 can be accurately measured. In addition, since the gate-leakage current is integrated and measured, a minute gate leakage current can be measured.

  FIG. 13 is a flowchart showing another example of a management method for managing each manufacturing apparatus 105 used in each manufacturing process for the managed manufacturing line 100. The management method in this example determines whether the plasma irradiation apparatus included in the managed production line 100 is good or bad.

  First, a first device and a second device manufactured by the same manufacturing line are prepared (S648). The first device and the second device may be manufactured, for example, by the reference manufacturing line 200 described with reference to FIG. The first device and the second device are devices having the same circuit configuration, and may include the test circuit 300 described with reference to FIG. 7 or FIG.

  Next, the first device is irradiated with plasma by the plasma irradiation apparatus used in the reference production line 200 (S650). Further, the second device is irradiated with plasma by the plasma irradiation apparatus used in the managed production line 100 (S652).

  Next, the characteristics of the first device and the second device irradiated with plasma are measured (S654). In S654, the characteristics of each device may be measured using the reference characteristic measurement unit 140 and the comparison characteristic measurement unit 142 described with reference to FIG.

  Next, the characteristics of the first device and the characteristics of the second device are compared (S656). And the quality of the plasma irradiation apparatus in the to-be-managed production line 100 is determined based on the difference in characteristics between the first device and the second device. The determination may be performed by the same method as the determination unit 160 described with reference to FIG. With this method, it is possible to determine whether the plasma irradiation apparatus in the managed production line 100 is good or bad.

  For example, when the plasma irradiation apparatus causes plasma damage greater than a reference value for an nMOS transistor, the threshold voltage of the transistor is reduced. On the other hand, the threshold voltage increases when plasma damage greater than the reference value occurs for the pMOS transistor. The determination unit 160 may determine the quality of the plasma irradiation apparatus based on the difference in threshold voltage of the transistors under measurement included in the first device and the second device.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing apparatus used for the manufacturing line which manufactures an electronic device can be managed correctly and easily.

It is a figure which shows an example of a structure of the management apparatus 10 which concerns on embodiment of this invention. 2 is a diagram illustrating an example of a configuration of a managed production line 100. FIG. 3 is a flowchart showing an example of the operation of the management apparatus 10. It is a chart which shows an example of processing when a device manufacturer has a managed production line 100 and a reference production line 200 has an external verification organization. It is a flowchart which shows an example of a process in the case of making one manufacturing line function as the reference | standard manufacturing line 200 among the several manufacturing lines which a device manufacturer has, and making another manufacturing line function as the management manufacturing line 100. FIG. An example of a top view of a wafer 500 on which a plurality of electronic devices 510 are formed by the managed production line 100 or the reference production line 200 is shown. 2 is a diagram illustrating an example of a circuit configuration of a test circuit 300. FIG. 10 is a flowchart illustrating an example of the operation of the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 when measuring variations in threshold voltage of each transistor under measurement 314 as the characteristics of the reference device and the comparison device. 10 is a flowchart showing an example of the operation of the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 when measuring variations in the current-voltage characteristics of the respective transistors under measurement 314 as the characteristics of the reference device and the comparison device. 10 is a flowchart illustrating an example of the operation of the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 when measuring variations in the PN junction leakage current of each transistor under measurement 314 as the characteristics of the reference device and the comparison device. 6 is a diagram illustrating another example of the circuit configuration of each cell 310 included in the test circuit 300. FIG. As the characteristics of the reference device and the comparison device, an example of the operation of the reference characteristic measurement unit 140 or the comparison characteristic measurement unit 142 when measuring the gate leakage current of each transistor under measurement 372 is shown. 12 is a flowchart showing another example of a management method for managing each manufacturing apparatus 105 used in each manufacturing process for a managed manufacturing line 100.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Management apparatus, 20 ... Device manufacturing system, 100 ... Managed production line, 105 ... Manufacturing apparatus, 110 ... Element separation process group, 114 ... Element formation process group, 118 ... Wiring formation process group, 120 ... Assembly process group, 130 ... Test process group, 140 ... Reference characteristic measurement part, 142 ... Comparative characteristic measurement part, 146 ... Measurement control part, 150 ... characteristic comparison unit, 160 ... determination unit, 170 ... comparison device production control unit, 200 ... reference production line, 210 ... element separation process group, 218 ... wiring formation process group , 300 ... Test circuit, 302 ... Column selection section, 304 ... Row selection section, 306 ... Column selection transistor, 310 ... Cell, 312 ... Switch transistor, 314 ... Transistor under test, 16 ... row selection transistor, 318 ... current source, 320 ... output unit, 371 ... gate voltage control unit, 372 ... transistor under measurement, 374 ... first switch, 376 ..Second switch 378 380 Reset transistor 382 Voltage application unit 384 NMOS transistor 386 PMOS transistor 388 capacitor 390 output Transistor, 392... Row selection transistor, 394... Stress applying unit, 500... Wafer, 510.

Claims (7)

A management method for managing each manufacturing apparatus used in each manufacturing process for a managed manufacturing line that manufactures an electronic device by a plurality of manufacturing processes,
A reference device manufacturing stage for manufacturing a reference device with a predetermined reference manufacturing line capable of performing the plurality of manufacturing steps;
A reference characteristic acquisition step of acquiring characteristics of the reference device;
A comparison device manufacturing stage in which at least one manufacturing process among the plurality of manufacturing processes is processed by the managed manufacturing line, another manufacturing process is processed by the reference manufacturing line, and a comparison device is manufactured.
A comparative characteristic measurement step for measuring the characteristic of the comparison device;
A characteristic comparison step of comparing the characteristics of the reference device and the characteristics of the comparison device;
A determination step of determining pass / fail of the manufacturing apparatus used in the manufacturing process of the managed manufacturing line that has processed the comparison device based on the difference in characteristics;
With
The reference device manufacturing stage and the comparative device manufacturing stage include
A plurality of measured circuits arranged in a two-dimensional matrix, each including a measured transistor;
A selection unit for outputting an output signal of the specified one circuit under measurement to an output signal line provided in common to the plurality of circuits under measurement;
The electronic device having a test circuit including the reference device and the comparison device are manufactured by the plurality of manufacturing steps,
The reference characteristic acquisition step includes:
In the test circuit of the reference device, a transistor selection step of sequentially selecting the plurality of measured circuits by the selection unit;
In the test circuit of the reference device, based on the output signal output from the selected circuit under measurement to the output signal line, the electrical characteristics of the transistor under measurement included in each circuit under measurement are measured. Output measurement stage and
Have
The comparative characteristic measurement step includes:
In the test circuit of the comparison device, a transistor selection step of sequentially selecting the plurality of measured circuits by the selection unit;
In the test circuit of the comparison device, based on the output signal output from the selected circuit under measurement to the output signal line, the electrical characteristics of the transistor under measurement included in each circuit under measurement are measured. Output measurement stage and
Management method with the. Each of the circuits under test is
A gate voltage controller for applying a specified gate voltage to the gate terminal of the transistor under measurement;
A reference voltage input unit for supplying a reference voltage input from the outside to one reference voltage side terminal of the drain terminal and the source terminal of the transistor under measurement;
A terminal voltage output unit that outputs, as the output signal, a terminal voltage of a terminal other than the reference voltage side terminal among a drain terminal and a source terminal of the transistor under measurement, provided that a selection signal is input from the outside. ,
The selection unit includes:
A row selection unit that outputs the selection signal to the circuit under measurement corresponding to a designated row among the plurality of circuits under measurement arranged in a two-dimensional matrix;
A column selection unit that selects a terminal voltage of the circuit under measurement corresponding to a specified column from the circuit under measurement to which the selection signal is input, and outputs the selected terminal voltage to the output signal line;
The test circuit is provided corresponding to each column of the plurality of circuits to be measured, and a plurality of currents for supplying a source-drain current designated to the circuit to be measured to which the selection signal is input by the row selection unit. Further including a source,
In the reference characteristic acquisition step and the comparison characteristic measurement step, the terminal voltage is measured as the electrical characteristic of each of the transistors under measurement.
The management method according to claim 1 . In the reference characteristic acquisition step and the comparison characteristic measurement step, a threshold voltage of the measured transistor is measured as the electrical characteristic for each of the measured transistors based on the reference voltage and the terminal voltage.
The management method according to claim 2 . In the characteristic comparison step, a variation in threshold voltages of the plurality of transistors under measurement included in the reference device is compared with a variation in threshold voltages of the plurality of transistors under measurement included in the comparison device.
The management method according to claim 3 . Each of the circuits under test is
A gate voltage controller for applying a specified gate voltage to the gate terminal of the transistor under measurement;
A voltage applying unit that applies a voltage to a source terminal and a drain terminal of the transistor under measurement and controls a voltage applied to a gate insulating film of the transistor under measurement to be substantially constant;
A capacitor for accumulating gate leakage current flowing from the gate terminal of the transistor under measurement to the source terminal and the drain terminal;
A capacitor voltage output unit that outputs, as the output signal, a capacitor voltage at an end of the capacitor on the source terminal and drain terminal side, provided that a selection signal is input from the outside;
In the reference characteristic acquisition step and the comparison characteristic measurement step, the capacitor voltage is measured as an electric characteristic of each of the transistors under measurement.
The management method according to claim 1 . For a managed production line that produces electronic devices by a plurality of production processes, a management apparatus that manages each production apparatus used in each production process,
A reference characteristic measuring unit that measures the characteristics of a reference device manufactured by a predetermined reference manufacturing line capable of executing the plurality of manufacturing steps;
A comparison device manufacturing control unit for manufacturing at least one manufacturing process among the plurality of manufacturing processes by the managed manufacturing line, causing other manufacturing processes to be processed by the reference manufacturing line, and manufacturing a comparative device;
A comparison characteristic measurement unit for measuring characteristics of the comparison device;
A characteristic comparison unit that compares the characteristic of the reference device and the characteristic of the comparison device;
A determination unit that determines the quality of the manufacturing apparatus used in the manufacturing process of the managed manufacturing line that has processed the comparison device based on the difference in characteristics;
The reference production line and the comparison device production control unit are arranged in a two-dimensional matrix, each of which includes a plurality of circuits under measurement each including a transistor under measurement, and a plurality of output signals of the specified circuit under measurement. The electronic device having a test circuit including a selection unit that outputs to an output signal line provided in common to the circuit under test is manufactured as the reference device and the comparison device by the plurality of manufacturing steps,
In the test circuit of the reference device, the reference characteristic measurement unit sequentially selects the plurality of circuits under measurement by the selection unit, and the selected circuit under measurement outputs the output signal line based on the output signal. Measuring the electrical characteristics of the transistor under measurement of each circuit under test,
In the test circuit of the comparison device, the comparison characteristic measurement unit sequentially selects the plurality of circuits under measurement by the selection unit, and the selected circuit under measurement outputs the output signal line based on the output signal. And a management device for measuring electrical characteristics of the transistor under measurement included in each circuit under measurement .   A device manufacturing method for manufacturing an electronic device by using the managed manufacturing line managed by the management method according to claim 1.

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