TW201910793A - Probe station - Google Patents

Abstract

An object of the invention is to provide a probing station with a simple configuration that enables batch contact to be performed. The probing station of the invention comprises a wafer stage having a mounting surface on which a semiconductor wafer is mounted, a probe card, a planar fine movement mechanism, and an optical unit. The probe card is substantially the same size as the wafer stage, and has an electrode capable of contacting the electrodes of every chip formed on the semiconductor wafer. The planar fine movement mechanism moves the mounting surface of the wafer stage within a plane that includes the mounting surface, by an amount equivalent to the degree of in-plane positional shift when mounting the semiconductor on the wafer stage. When positioning the wafer stage, the optical unit is disposed between the probe card and the wafer stage, and captures images of the electrodes of the semiconductor wafer and the electrode of the probe card.

Description

Detection station

The invention relates to a detection station.

In recent years, in various scenes, a large amount of data has been sought to be stored, organized, and utilized, and semiconductor memory has been used as its main memory medium. The semiconductor memory system is formed on a semiconductor wafer in which minute patterns are drawn and exposed, and is sealed in a package body after being tested for electrical characteristics. The semiconductor wafer is mostly formed on one semiconductor wafer. In the electrical characteristic test, a probe station is used to touch the electrodes of the probe card to the electrodes of the semiconductor wafer (for example, refer to Patent Document 1 or 2).

In terms of reducing the unit price of the semiconductor memory, the following methods are effective: miniaturize the wiring pattern formed on the semiconductor wafer, or increase the diameter of the semiconductor wafer, and increase the number of semiconductor wafers that can be taken out from one semiconductor wafer. In addition, the following method is also effective: by performing measurement of a plurality of semiconductor wafers at the same time, the time for testing the electrical characteristics is shortened, and as a result, the number of semiconductor wafers that can be taken out at the same time is increased.

In view of this situation, in recent years, various semiconductor manufacturers have increased the diameter of semiconductor wafers and measured many semiconductor wafers simultaneously. As for the most efficient method for such multiple simultaneous measurement, there are the following methods: touch them together to make the electrodes of the probe card contact the semiconductor wafer on the entire surface of the semiconductor wafer.

In addition, when a conventional probe station is used to touch all the semiconductor wafers formed on the semiconductor wafer together, the probe card is aligned with the semiconductor wafer alignment position, and then the probe card is brought to a predetermined position at one time. , The so-called step movement.

Here, the conventional detection station was developed on the premise that while measuring most semiconductor wafers at the same time, the distance of an integer multiple of the wafer size of the majority of semiconductor wafers formed on the semiconductor wafer is moved and divided into multiple times. Perform measurement of electrical characteristics. Therefore, in the conventional detection station, the mechanical stroke of the stepping movement is maintained under the condition that the measurement in units of one wafer is basic. For example, among 12-inch wafer-compatible models, a minimum of 300 mm travel is required for the XY axis. And it must be high precision in the whole range of this trip. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Application Publication No. 2006-339196 Patent Document 2: Japanese Patent Application Publication No. 2007-095753

[Problems to be solved by the invention]

However, with the increase in the diameter of semiconductor wafers, mechanisms that move distances that are integral multiples of the size of the wafers, and the accuracy and rigidity required to measure the majority of semiconductor wafers at the same time, have dramatically improved in recent years. In the conventional detection station, in order to cope with the deviation of the center position of the probe card from the semiconductor wafer, that is, the moment caused by the offset load in the vertical direction caused by the offset and touch, a special Z axis must be used. , Or very rigid guide mechanism.

Therefore, the difficulty in designing and manufacturing the detection station is increasing.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a detection station with a simple structure for contacting all the electrodes of a wafer formed on a semiconductor wafer together. [Technical means to solve problems]

In order to achieve the above object, the detection station for measuring the electrical characteristics of a semiconductor wafer of the present invention is purchased to include: a wafer stage, which mounts a semiconductor wafer on a mounting surface; a probe card; a planar micro movement mechanism; and an optical system unit.

The probe card is approximately the same size as the wafer stage and has an electrode that can touch the electrodes of all wafers formed on the semiconductor wafer. The planar micro movement mechanism moves a mounting surface of a wafer stage within a plane including the mounting surface, and moves the plane position with a precision of deviation in plane position when a semiconductor wafer is mounted on the wafer stage. The optical system unit is arranged between the probe card and the wafer stage during the positioning of the wafer stage, and photographs the electrodes of the semiconductor wafer and the electrodes of the probe card respectively. [Effect of invention]

The detection station according to the present invention comprises: a probe card, which is approximately the same size as a wafer stage and has electrodes, which can touch the electrodes of all wafers formed on the semiconductor wafer; and the purpose is to touch the semiconductor wafer all at once The electrodes of all the wafers formed on it. Therefore, after the alignment of the alignment position of the probe card and the wafer stage, the contact between the electrodes of the semiconductor wafer and the electrodes of the probe card can be performed without performing "step movement".

As a result, the planar micro movement mechanism can move a sufficient amount of deviation that may occur when the semiconductor wafer is mounted on the wafer table to align the position in the plane. There is no need for a conventional detection station for The required travel.

Moreover, in the detection station of the present invention, the probe card and the semiconductor wafer must be in contact with each other only at a determined position, and therefore, no unnecessary torque is generated in the Z axis. Therefore, the proper design and manufacture of vertical loads is easy.

[The best form of implementing the invention]

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the shape, size, and arrangement relationship of each constituent element are only shown to the extent that the present invention can be understood. In addition, some illustrations and descriptions of the constituent elements may be omitted.

In the following, preferred configuration examples of the present invention will be described, but these are only preferred examples. Therefore, the present invention is not limited to the following embodiments, and many changes or modifications that can achieve the effects of the present invention can be made without departing from the scope of the present invention.

The detection station of the present invention will be described below with reference to FIG. Figure 1 illustrates the detection station of the present invention. FIG. 1 (A) is a schematic view of the detection station viewed from the side, and FIG. 1 (B) is a schematic diagram illustrating a configuration example of a planar micro movement mechanism provided by the detection station, and is a schematic view viewed from the outer top surface.

The detection station of the present invention includes, for example, a test head 10, a performance board 20, a probe card 30, a wafer table 60, a pressure sensor 80, a Z-axis moving mechanism 90, a planar micro moving mechanism 70, and an optical unit 40. .

When the test head 10 performs an electrical characteristic test, it responds to an instruction from the outside, sends a test signal to the semiconductor wafer 50, and evaluates a response signal output from the semiconductor wafer 50.

The performance board 20 is disposed between the test head 10 and the probe card 30. The signal transmission between the test head 10 and the probe card 30 is performed through the performance board 20.

The probe card 30 includes electrodes (or probe pins and probes) that can touch the electrodes of all the semiconductor wafers formed on the semiconductor wafer 50. Therefore, the probe card 30 has an aperture that is at least approximately the same size as the semiconductor wafer 50. The number of electrodes provided on the probe card 30 may be 20,000 or more.

The wafer stage 60 mounts a semiconductor wafer 50 on its mounting surface. Therefore, the diameter of the wafer stage 60 is slightly larger than the diameter of the semiconductor wafer 50. Here, the plane including the mounting surface of the wafer stage 60 is defined as an XY plane, and an axis orthogonal thereto is defined as a Z axis.

The optical unit 40 is disposed between the probe card 30 and the wafer stage 60 when the wafer stage 60 moves in a small manner in the XY plane, that is, during positioning. This optical unit 40 is configured to include an upper-view optical system and an upper-view optical microscope, capable of simultaneously capturing the electrodes of the semiconductor wafer 50 and the electrodes of the corresponding probe card 30. For example, the optical unit 40 can be configured using an imaging mechanism 42 and a lens 44 such as a camera.

In the conventional detection station, as for the imaging mechanism for positioning the probe card and the semiconductor wafer, the optical system for aligning the probe card above and the optical system for aligning the wafer below are separately prepared, and Positioning is performed using parameters for position correction between optical systems.

In a conventional detection station, the probe card alignment optical system must be moved together with the wafer stage. Therefore, in order to confirm the positional relationship with the optical system for wafer alignment, the positions where the optical axes of the two optical systems are consistent must also be included in the moving range. Therefore, the conventional detection station must be able to move with a stroke larger than the stroke corresponding to the wafer diameter.

On the other hand, if positioning is performed using the optical unit 40 including the upper and lower field-of-view optical system, it is possible to easily perform positioning in the XY plane without the need for position correction between a large number of optical systems. Furthermore, the necessary extension of the travel distance of the conventional detection station becomes unnecessary.

The positioning in the XY plane is performed in such a manner that the planar micro movement mechanism 70 moves the wafer stage 60 in the XY plane according to the result of the imaging by the optical unit 40.

The planar micro movement mechanism 70 is achieved by a four-axis platform having four drive shafts, for example, X1, X2, Y1, and Y2. When the X1 drive shaft 74a and the X2 drive shaft 74b are moved in the same direction, the wafer stage 60 moves along the X axis. That is, the X1 drive shaft 74a and the X2 drive shaft 74b function as an X drive shaft which moves the wafer stage 60 along the X axis.

Similarly, if the Y1 drive shaft 76a and the Y2 drive shaft 76b are moved in the same direction, the wafer stage 60 moves along the Y axis. That is, the Y1 drive shaft 76a and the Y2 drive shaft 76b function as a Y drive shaft which moves the wafer stage 60 along the Y axis.

If the movement amounts of the four drive shafts X1, X2, Y1, and Y2 are appropriately set, they will move in the rotation direction. That is, the four drive shafts X1, X2, Y1, and Y2 function as θ drive shafts.

In addition, the movement amounts of the four drive axes of X1, X2, Y1, and Y2, that is, a movement amount of about 4 mm on the 4-axis stage is sufficient, which can correct the mounting of the semiconductor wafer 50 on the wafer table 60. Positional deviations caused by the transportation of robots, etc. As described above, the planar micro movement mechanism 70 is preferably configured by using a platform such as driving XYθ on one plane, which is constituted by a thin thickness as a whole, and rigidity is easily secured.

In the conventional detection station, in addition to the amount of movement in order to touch the entire area of the semiconductor wafer and the amount of movement to align the optical system, positioning accuracy of about several μm is required in the entire area. In contrast, in the detection station of the present invention, the required amount of movement is sufficient in terms of the transport accuracy (about several mm) of a robot or the like that mounts a semiconductor wafer on a platform, which can make it easier. Make up. In addition, the amount of movement of the planar micro movement mechanism 70 in the detection station of the present invention does not depend on the size of the target semiconductor wafer.

Here, an example in which the planar micro movement mechanism 70 is configured using a four-axis stage having four drive shafts is described, but it is not limited to this. It is only necessary to use an appropriate mechanism having a movement amount that is about the carrying accuracy of a robot or the like and a positioning accuracy of about several μm. Instead of a 4-axis platform, a platform using the X-axis, Y-axis, and θ-axis as the drive shaft or a U-axis, V-axis, and W-axis as the drive shaft may be used.

The Z-axis moving mechanism 90 moves the wafer stage 60 in a direction orthogonal to the mounting surface, that is, in the Z-axis direction. The Z-axis moving mechanism 90 may be configured to include, for example, a driving motor and a screw, which are moved up and down by the operation of the motor.

The Z-axis moving mechanism 90 moves the wafer stage 60 in a state where the positioning of the probe card 30 and the wafer stage 60 in the XY plane is completed, and brings the probe card 30 into contact with the semiconductor wafer 50. A pressure sensor 80 such as a load cell is mounted on a driving portion of the axis of the Z-axis moving mechanism 90. For example, when the entire semiconductor wafer 50 includes 20,000 electrodes, and each unit electrode is contacted with a contact pressure of 10 g, the load applied to the drive shaft by the Z-axis moving mechanism 90, that is, the contact pressure of the entire semiconductor wafer 50, is about It is 2000N. Therefore, if the result of measuring the contact pressure by the pressure sensor 80 is that the contact pressure becomes a predetermined value (about 2000 N in this case), it can be considered that the electrodes of the probe card 30 and the electrodes of the semiconductor wafer 50 are sufficient. touch.

In addition, after the alignment is completed, before entering the detection, the optical unit 40 is retracted to a position where no dryness occurs even if the wafer table is raised along the Z axis.

(Other configuration examples) In the current detection station, since the amount of movement in the XY plane of the wafer stage is large, the test head is disposed on the upper side and the probe card is disposed downward as in the above-described configuration example.

However, sometimes the test head will have a large size of about 1m in length, width, and height, and the weight will be nearly 1t. When the probe card is replaced or the test head unit is maintained, the test head must be turned and moved to the ground. Therefore, there must be a mechanism to turn the test head, and the installation area and weight of the device become large.

In contrast, in the configuration example described above, the amount of movement in the XY plane of the wafer stage 60 is small. As a result, the wafer stage 60, the planar micro movement mechanism 70, and the Z-axis movement mechanism 90 can be miniaturized in structure. As a result, the weight is also several hundreds of kg less than that of the test head 10.

Therefore, the detection station not only includes a Z-axis moving mechanism 90, a pressure sensor 80, a planar micro moving mechanism 70, a wafer stage 60, a probe card 30, a performance board 20, or a test head 10 in this order from the ground side. It can also be turned upside down. That is, the test head 10 can be installed on the ground side. At this time, the detection station is configured in order from the ground side to include: a test head 10, a performance board 20, a probe card 30, a wafer table 60, a planar micro movement mechanism 70, a pressure sensor 80, and a Z-axis movement mechanism 90. . At this time, the probe card 30 is arranged so that the electrodes are on the upper side, and during the measurement, the wafer stage 60 is moved downward, so that the semiconductor wafer 50 contacts the probe card 30 from the upper side.

With this configuration, a large-scale mechanism that does not require the test head 10 to be turned over can have a simple structure.

10‧‧‧test head

20‧‧‧ Performance Board

30‧‧‧ Probe Card

40‧‧‧optical unit

42‧‧‧ filming agency

44‧‧‧ 稜鏡

50‧‧‧Semiconductor wafer

60‧‧‧Wafer Table

70‧‧‧Plane micro movement mechanism (alignment platform)

74a‧‧‧X1 drive shaft

74b‧‧‧X2 drive shaft

76a‧‧‧Y1 drive shaft

76b‧‧‧Y2 drive shaft

80‧‧‧ Pressure Sensor

90‧‧‧Z axis moving mechanism

[Figure 1] (A), (B) are used to explain the detection station of the present invention.

Claims (3)

A detection station for measuring the electrical characteristics of a semiconductor wafer, comprising: a wafer stage, on which a semiconductor wafer is mounted; and a probe card, which is approximately the same size as the wafer stage and has electrodes. The electrode can touch the electrodes of all the wafers formed on the semiconductor wafer; and the optical system unit is disposed between the probe card and the wafer stage when the wafer stage is positioned, and respectively photographs the semiconductor The electrode of the wafer and the electrode of the probe card; and the plane moving mechanism of the wafer stage includes only the following mechanism: a plane micro movement mechanism, so that the mounting surface is within the plane including the mounting surface to a maximum To move the semiconductor wafer to the wafer stage, the plane position deviation has a precision of magnitude; and the plane micro movement mechanism drives XYθ in a plane, and uses X1, X2, Y1, Y2, etc. The four-axis stage with four drive axes, the XYθ stage with X-axis, Y-axis, and θ-axis as the drive axis, or the UVW stage with U-axis, V-axis, and W-axis as the drive axis. The optical system unit is configured as: Contains by 1 The imaging mechanism down-field optical system constituted Prism. For example, the detection station of the scope of application for patent No. 1 further includes: a Z-axis moving mechanism for moving the wafer stage in a direction orthogonal to the mounting surface; and a pressure sensor mounted on the Z-axis moving mechanism Measure the contact pressure between the semiconductor wafer and the probe card. For example, the probe station according to item 1 or 2 of the patent application scope, wherein the probe card is configured to face upward, and the wafer table is moved downward to contact the semiconductor wafer to the probe card.