JPH0758167A - Probing device - Google Patents

Abstract

PURPOSE:To align the bumps of a probe card with the electrode pads of a wafer simply and accurately in a temperature test. CONSTITUTION:By the arranging of bumps 3 on the surface of a polyimide thin film, a probe card 2 is configured, and concurrently, scales 41, 42 are formed respectively in X and Y directions in the periphery of the arrangement of the bumps 3, e.g. by an exposure technique. In case of ordinary temperature, the coordinates of the bumps on the probe card 2 are stored beforehand in a storage part, and in case of the thermal expansion of the probe card, the scales 41, 42 are read by a photographing unit. Based on the read results and the coordinates of the bumps, the data of the coordinates of the bumps at the present time are calculated, and thereby, the position of a wafer putting-on base is controlled.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a probe device.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process,
After the wafer process is completed and the IC chip is completed in the silicon wafer, electrical measurement called a probe test is performed to check the short circuit and the open of the electrode pattern and the input / output characteristics of the IC chip. Hereinafter, the quality of the IC chip is determined in the "wafer" state. After that, the wafer is divided into IC chips,
After the good IC chip is packaged, for example, a predetermined probe test is performed to judge the quality of the final product.

In this probe device, a wiring board called a probe card having probe needles is used. This probe card is provided with a contact group on one surface side of the insulating substrate and one end is connected to each of these contact groups. Further, the other end of the probe needle made of, for example, tungsten is obliquely extended and configured. When performing the measurement, the contacts formed on the probe card are electrically connected to the electrodes on the test head side, while the probe needles and the electrode pads of the chips on the wafer are aligned by the movement of the wafer mounting table, and then the The test signal is input from the test head to the chip through the probe card, and the chip is electrically measured based on the output signal from the chip.

As a method of aligning the probe needle with the electrode pad on the wafer, the probe needle is brought into contact with a dummy wafer placed on the wafer mounting table, the needle trace is monitored by a camera, and the operator traces the needle trace. Method to adjust the position of the wafer mounting table, or monitor the tip of the probe needle with a camera and separately monitor, for example, two cross marks of the wafer on the wafer mounting table with a camera, and based on both monitoring results. Similarly, a method of adjusting the position of the wafer mounting table is adopted.

[0005]

By the way, in recent years, devices have tended to be further miniaturized and highly integrated, and along with this, the electrode pads of the chip have been miniaturized, and the array pitch thereof has been narrowed. The size of the electrode pad is currently about 70 μm on one side, and the tip of the probe needle is about 30 μm.
Although it is about m, if the electrode pads become finer and the pitch thereof becomes narrower, it becomes very difficult to set the probe needle arrangement.

Therefore, recently, it has been considered to form bumps, which are conductive protrusions such as 18 gold or copper, as contacts on a thin film substrate made of a resin such as polyimide. According to such a probe card, minute bumps can be accurately formed in a predetermined array pattern on an insulating substrate by using, for example, a printing technique, and is expected to be suitable for future devices. .

On the other hand, in addition to the test at room temperature, the IC chip may be subjected to electrical measurement under conditions of high temperature or low temperature, and further, the IC chip is subjected to an accelerated test under severe conditions to detect a defective product in advance. In some cases, the burn-in test is performed on the wafer. In such a test, the wafer may be heated to a temperature of, for example, about 150 ° C., and the probe card is also heated at that time, so that the probe card undergoes thermal expansion and the position (coordinate position) of the bump on the card changes. Therefore, it is necessary to grasp the change and align the probe card and the wafer again after the room temperature test, for example.

If this alignment is carried out by inheriting the conventional method, for example, two marks on the probe card are monitored from below by a camera, and the thermal expansion of the probe card, that is, the bump arrangement. A method of grasping the situation and aligning the position of the wafer with a position corresponding to the bump arrangement at this time can be considered, but this method cannot grasp the coordinate position of the bump over the details of the bump arrangement region, For example, if the degree of thermal expansion is locally different, not all bumps will surely come into contact with the electrode pads, especially for those having a large number of bumps and a high arrangement density. There is also a problem that the work is troublesome because the coordinate position of the bump must be predicted based on the monitor result for each type of probe card.

On the other hand, a method of monitoring all the bumps with a camera is conceivable, but the work of checking all the arrangements of the bumps is very troublesome, and it is necessary to look at all the bumps and grasp the state of their coordinate positions. Is extremely difficult. In addition, in this method, when performing a test at a high temperature following a test at a normal temperature, it is necessary to perform alignment at the normal temperature and then perform the same operation in a state of being heated again, which is extremely efficient. Is bad.

The present invention has been made under such circumstances, and its purpose is to be able to accurately and easily grasp the change in the coordinate position of the contact of the probe card, and thereby to improve the accuracy. It is an object of the present invention to provide a probe device capable of performing high-level alignment.

[0011]

According to a first aspect of the present invention, a contactor electrically connected to a measuring unit and arranged on a probe card is brought into contact with an electrode pad of an object to be inspected on an object to be inspected table. In a probe device for electrically measuring an object to be inspected by a measuring unit, scales formed on the probe card so as to be aligned in the X and Y directions along the circumference of the array region of the contacts, respectively, A recognizing means for recognizing the scale is provided.

According to a second aspect of the present invention, a memory unit that stores the coordinate positions of the X and Y axis contacts in the probe card, the recognition result of the scale recognized by the recognition means, and the contacts stored in the memory unit. And a relative position of the object mounting table with respect to the probe card based on the coordinate position of the contactor obtained by this operation unit. And a control unit.

[0013]

When performing a high temperature (or low temperature) test, the scale of the probe card is recognized by the recognition means, and based on the recognition result and the coordinate position data of the contact at normal temperature, the current coordinate position data of the contact is detected. Ask for. Therefore, since the coordinate position data of the contactor can be accurately grasped over the details of the bump arrangement area, the contactor and the electrode pad can be controlled by controlling the position of the object mounting table with respect to the probe card based on this data. Can be accurately aligned.

[0014]

1 to 3 are views showing the outline of the overall construction of an embodiment of the present invention. In the figure, reference numeral 1 is a wafer mounting table. The wafer mounting table 1 has a heater 11 and a temperature adjusting means including a coolant flow path (not shown) built therein, and the temperature of the wafer W is, for example, in the range of −40 ° C. to 150 ° C. It is configured to be adjustable. The wafer mounting table 1 is driven by the driving mechanism 12 in a small amount, for example, in the X, Y, θ (around the vertical axis) direction, and can be moved up and down between the inspection position and the transfer position.

A probe card 2 is provided on the upper surface of the wafer mounting table 1 so as to face it. The probe card 2 is provided with a card main body 21 formed by forming a plurality of conductive layers forming signal paths in a polyimide thin film, for example, and a contactor, for example, a conductive protrusion is provided on the lower surface of the card main body 21. The bumps 3 are arranged. As shown in FIG. 2, the bumps 3 are arranged corresponding to all the electrode pads of the wafer W, for example, so as to collectively contact the electrode pads of all the chips, for example, 18 gold,
It is composed of platinum, rhodium, tungsten or nickel alloy.

On the lower surface side of the card body 21, along the periphery of the arrangement area of the bumps 3, in this example, along one side of the square in which the arrangement area of the bumps 3 fits and the other side orthogonal thereto, X, Scales 4 (41) and 4 (42) respectively in the Y direction
When the diameters and the arrangement pitches of the bumps 3 are 50 μm and 100 μm, respectively, the width of one graduation 4 itself and the interval between the graduations 4 are 25 μm and 25, respectively.
It is set to a length of μm. These graduations 41 and 42 can be formed on the surface of the polyimide thin film with a highly accurate width and pitch by using an exposure technique in the process of manufacturing a probe card using the above-mentioned thin film. The probe card 2 is made according to the type of the wafer W, but a display corresponding to the type of the probe card, such as a bar code 22 or an OCR (optical), is provided on the lower surface of the card body 21.
Character 23 for character reader) is attached.

At the peripheral portion of the upper surface of the probe card 2,
The probe card 2 is attached to a rectangular ring-shaped frame 5 corresponding to the shape of the probe card 2, and the frame 5 is attached to a performance board 52 which is a wiring board on the lower surface side of the test head 51. Although not shown, a bump for connection, which is electrically connected to the bump 3 through a through hole formed in the polyimide thin film (card body 21) or a conductive layer, is provided on the peripheral edge of the upper surface of the probe card 2. The bumps are arranged and electrically connected to the performance board 52 on the test head 51 side through conductive paths such as electrode shafts in the frame body 5.

On the upper surface side of the probe card 2, for example, a heater 24 formed by forming a resistance heating layer on a flexible insulating substrate is attached. Further, a buffer 25 such as an air mat or a rubber body is sandwiched between the central space of the frame body 5, that is, between the probe card 2 and the performance board 52, against the restoring force of the buffer body 25 itself.
1 will be pressed to the lower surface side.

Between the wafer mounting table 1 and the probe card 2, alignment marks (cross marks, L-shaped marks, etc.) formed on the wafer W on the wafer mounting table 1 are aligned.
Also, an image pickup unit 6 for monitoring the alignment marks formed on the probe card 2 side and for monitoring the scales 4 (41, 42) on the probe card 2 side is provided so as to be movable back and forth. This imaging unit 6
Is an objective lens 61 for the bump 3 and an objective lens 62 for the electrode pad P, a camera 63 for forming an image of the bump and the electrode pad P, and an image from the upper objective lens 61 for example as shown in FIG. A half mirror 64 that reflects to the 63 side, and a mirror 6 that forms an optical path from the lower objective lens 62 to the back surface side of the half mirror 64.
5 and the prism 66, and shutters 67 and 68 for independently opening and closing the optical paths from the upper objective lens 61 and the lower objective lens 62, respectively.

Here, the image pickup unit 6 includes a drive mechanism M.
Is supported by a support mechanism 7 that can move in the X and Y directions, and encoders E (E ₁ and E ₂ ) are connected to the X-direction motor and the Y-direction motor that form the drive mechanism M, respectively.

On the other hand, the image obtained by the image pickup unit 6 is taken into the image processing section 81 in the control unit 8 through an optical path such as an optical fiber. The control unit 8 includes a scale data processing section 80, a first
The storage unit 82, the calculation unit 83, the second storage unit 84, the control unit 85, and the like. The image processing unit 81 has a function of converting the image obtained by the image pickup unit 6 into electronic data, and the image of the bump 3 and / or the electrode pad on the wafer W is transferred via the image processing unit 81 in the alignment mode. For example, it is displayed on a separately provided CRT device 86.

The first storage section 82 stores data on the coordinate position of each bump 3 in the X and Y coordinate systems on the probe card 2 for each type of probe card 2. This data shows the coordinate position of the bumps 3 when the scales 4 are arranged according to the standard (no stretch or shrinkage). The scale data processing unit 80 is based on the images of the scales 41 and 42 sent from the image processing unit 81 and the pulses from the encoders E1 and E2 in the X direction and the Y direction.
For example, as shown in FIG. 4, it has a function of obtaining the interval of each graduation for each direction with binary graduation data. In this embodiment, the image pickup unit 6, the encoders E1 and E2, and the scale data processing unit 80 constitute a scale recognizing unit.

The calculation unit 83 decodes the bar code 22 and the OCR characters 23 on the probe card 2 sent from the image processing unit 81 to determine the type of the probe card, and determines the probe card type according to the type. Based on the function of reading the coordinate position data of the bump from the first storage unit 82, the data from the scale data processing unit 81, and the coordinate position of the bump read from the first storage unit 82, It has a function of calculating the coordinate position of the bump and storing it in the second storage unit 84.

The control unit 85 determines the position of the wafer W relative to the probe card 2 based on the current coordinate position of the bump stored in the second storage unit 84 and the coordinate position of the electrode pad on the wafer W. It has a function of moving the wafer mounting table 1 optimally, that is, at this time (for example, when the probe card is heated), all the bumps surely contact the electrode pads.

Next, regarding the operation of the above-described embodiment, first, the heater 11 on the wafer mounting table 1 side and the heater 24 on the probe card 2 side are turned on to turn on the wafer W and the probe card 2.
Is heated to a temperature of, for example, about 150 ° C., and an object to be inspected, for example, a wafer W is mounted on the wafer mounting table 1. Then wafer W
The imaging unit 6 between the probe card 2 and
For example, at two predetermined positions, the images of the alignment marks formed on the wafer W are captured by the image pickup unit 6 and displayed on the CRT device 86, so that the operator can bring these marks to predetermined positions on the screen. The wafer mounting table 1 is manually driven.

Subsequently, the image pickup unit 6 monitors each of the scales 41 and 42 of the probe card 2 from one end to the other end, and the length between the scales is calculated by the arithmetic unit 83 as described above. On the other hand, the bar code 22 and the OCR character 23 of the probe card 2 are imaged by the imaging unit 6 and decoded by a data processing unit (not shown) to determine the coordinate position of each bump 3 on the probe card of the corresponding type as the first position. Read out from the storage unit 82. The calculation unit 83 obtains the coordinate position of each bump 3 of the current (thermally expanded) probe card 2 based on this data and the length of the scale, and stores the coordinate position in the second storage unit 84. The wafer W is aligned with the probe card 2 by referring to the data in the storage section 84.

This alignment is performed by the controller 85 of the wafer mounting table 1 so that all the bumps 3 come into contact with the corresponding electrode pads based on the bump data and the coordinate position data of the electrode pads of the wafer W. This is performed by determining the amount of movement in the X and Y directions and moving the wafer mounting table 1 by this amount of movement. In this case, for example, referring to FIG. .. to 34, the first to fourth electrode pads P1 to P4 are located at the positions shown in FIG. 5, and the second bump 32 having the largest displacement with respect to the corresponding electrode pad coincides with the electrode pad P2. It is also possible to perform alignment such as driving the wafer mounting table 1 as described above. After the alignment is performed in this way, the wafer mounting table 1 is raised to bring the bumps 3 arranged on the probe card 2 into contact with the electrode pads of all the chips of the wafer W at once. At this time, the buffer 25
Due to the restoring force of, the bump 3 comes into contact with the electrode pad of the chip in a pressed state, and reliable electrical contact is achieved. Then, a predetermined pulse signal is applied from the test head 5 to the chip of the wafer W, and the pulse signal from the chip side is applied to the test head 5.
To determine whether the chip is good or bad.

According to the embodiment described above, the scale 4 (41, 4)
2) is recognized and the coordinate position data of the bump 3 at the time of thermal expansion is grasped based on the intervals between the scales and the coordinate position data of the bump 3 at room temperature. It is possible to accurately grasp the coordinate position data of the bumps, and therefore which bump and electrode pad pair is to be used as a reference for alignment, and in that case, the position of all pairs can be adjusted by setting the amount of movement. Since it can be determined whether or not they match, the bumps can be reliably brought into contact with the electrode pads of the wafer W by controlling the position of the wafer mounting table 1 based on this data. Then, while reading the barcode 22 and the OCR character 23, the scale 4 (4
Since it is only necessary to recognize (1, 42), the coordinate position data of the bump at the time of thermal expansion can be easily grasped.

Next, an example of a specific mechanism for moving the image pickup unit 6 is shown in FIGS. 6 and 7, and in this embodiment, a close contact is made between the separable aluminum cover portion 71 and base portion 72. A holding frame 91 having a shape corresponding to these is provided so as to be able to intervene.
The cover part 71 and the base part 72 are provided with the probe card 2 and the wafer mounting table 1, respectively. The cover part 71 receives the temperature adjusting fluid from the introduction part 71a into the damper chamber 71b and the discharge part 71c. Configured to be discharged from. Further, in FIG. 6, 73 is a bump electrically connected to the bump 3, 74 is an electrode, 75 is a connector, and 76 is a cable connected to the test head.
After removing, the cover portion 71 and the base portion 72 are brought into close contact with each other, and the bumps 73 are connected to the connector 75 via the electrodes 74.

X guide rails 92 and 92 and Y guide rails 93 and 93 which are guided by the X guide rails 92 and 92 and extend in the Y direction are provided on both left and right edges of the holding frame 91.
Are arranged, and the imaging unit 6 includes an indirect arm 9
4 and is guided along the Y guide rails 93, 93, and thus configured to be movable in the X and Y directions.

In the above, the present invention can be applied not only to the high temperature test but also to the low temperature test, and also in the normal temperature test, the scale is recognized and the distortion of the probe card is checked to determine the unusable state. It may be applied when checking whether or not When making such a check, the state of the probe card may be determined only by recognizing the scale 4.

The bumps are not limited to be arranged so as to be in contact with the electrode pads of all the chips of the wafer at once, and the bumps may be arranged corresponding to the electrode pads of one chip or a plurality of chips, for example. Good. The X and Y directions, which are the arranging directions of the scales, are not limited to being orthogonal to each other, but include a case where they are obliquely crossed.

[0033]

According to the invention of claim 1, since the scale is formed on the probe card along the periphery of the arrangement region of the contacts, the strain such as expansion and contraction of the probe card can be easily grasped. The change in the coordinate position of the contact can be grasped. Therefore, it is possible to easily perform accurate alignment between the device under test and the probe card, determination of unusability, and the like.

According to the invention of claim 2, the coordinate position of the contact at that time is obtained based on the recognition result of the scale and the coordinate position data of the contact stored in advance. Can be grasped easily and accurately, highly accurate alignment can be performed, and the contactor and the electrode pattern can be surely brought into contact with each other.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a plan view showing a probe card according to an embodiment of the present invention.

FIG. 3 is a side view showing an example of an image pickup unit.

FIG. 4 is an explanatory view showing the scales of the probe card and their intervals.

FIG. 5 is an explanatory diagram showing an example of a positional relationship between electrode pads and bumps.

FIG. 6 is a sectional view showing another embodiment of the present invention.

FIG. 7 is a plan view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer mounting table 2 Probe card 21 Card body 3 Bumps 4, 41, 42 Scale 5 Test head 6 Imaging unit 82 First storage section 83 Computing section 84 Second storage section 85 Control section

Claims (2)

[Claims] 1. An electrical measurement of an object to be inspected by the measuring unit, by contacting a contactor electrically connected to the measuring unit and arranged on a probe card with an electrode pad of the object to be inspected on a table to be inspected. In the probe device for performing the above, the probe card is provided with graduations formed so as to be aligned in the X and Y directions along the periphery of the arrangement area of the contactors, and a recognition means for recognizing the graduations of the probe card. A probe device characterized by the above. 2. A storage unit that stores the coordinate positions of the X and Y axis contacts in the probe card, a scale recognition result recognized by the recognition means, and the coordinate positions of the contacts stored in the storage unit. And a controller for determining the coordinate position of the contactor at that time based on the coordinate position of the contactor determined by the calculator, and a controller for determining the relative position of the object mounting table with respect to the probe card. A probe device characterized by being provided.