JPH0370900B2 - - Google Patents

Description

[Detailed description of the invention]

"Purpose of invention"

[Industrial application field]

The present invention relates to a prober for measuring chips in a wafer, and particularly to a prober equipped with a test head, which is compatible with a wide variety of wafers, automatically replaces a board with a probe card as a single product, and also allows probe card needle alignment. The present invention relates to a wafer prober whose operation is automated, thereby making the system unmanned.

[Conventional technology]

The wafer prober measures the electrical characteristics of each chip within the wafer and eliminates chips determined to be defective before the assembly process.
This is a device that contributes to cost reduction or productivity improvement. By the way, recent semiconductor manufacturing processes require improvements in productivity, yield, and quality, and as wafers are becoming larger in diameter and manufacturing equipment is becoming more automated, the same applies to probers. The prober has been improved to the present day, and is capable of automatically transferring and measuring wafers from the wafer cassette in which the wafers are stored. However, with the recent increase in the integration of chips, the number of low-volume, high-mix production processes has increased, and the reality is that the number of operations required by operators has increased significantly. For example, when measuring a wafer of X type and then a wafer of Y type, the probe card must be replaced with one appropriate for Y type, and depending on the type, the performance board attached to the board and test head must be replaced. must also be replaced. Generally, in the above case, the operator loosens the screws etc. on the head plate and manually replaces the board containing the probe card suitable for the Y type. Furthermore, depending on the product type, the performance board attached to the test head must be replaced with one for the Y product type. Under these circumstances, the applicant of the present application proposed Japanese Patent Application No. 10738/1983 to develop a prober that enables automatic replacement of the probe card itself. To summarize this application, there is provided a storage device having a plurality of accommodation grooves for accommodating a plurality of probe cards, and a protection plate 6 for protecting the stylus portion of the probe card.
A probe card set, which is formed from a ring for suctioning and fixing the probe card and a substrate corresponding to the electrode parts arranged on the probe card, and in which the probe card is covered with a protective plate, is housed in the housing.
A means for transporting the wafer to the measurement section is shared, and the probe card set is transported to the measurement section and fixed to the ring by suction.

[Problem to be solved by the invention]

However, the former type of prober requires an operator to be replaced every time the product is changed, which is not only contrary to automation in the semiconductor manufacturing process, but also difficult to improve productivity, yield, quality, etc. Extremely difficult. In particular, the stylus of the probe card lacks durability due to friction against the tip, so in order to obtain highly reliable measurement results, it is necessary to repeatedly replace the probe card, which reduces work efficiency. It was declining. Secondly, since the latter prober can automatically replace a single probe card, it can satisfy the demands for improved productivity for limited types of probers compared to the former, but it is not suitable for all general semiconductors. It is not automated for varieties. In a multi-product production line, there was a strong desire to build an unmanned system using a more advanced prober for all products. In view of the above circumstances, the present invention solves all the conventional problems at once, and also builds an unmanned prober system that meets the above demands, thereby improving productivity, yield, and quality. It is an object of the present invention to provide a wafer prober that can be improved. "Structure of the invention"

[Means to solve the problem]

In order to achieve the above object, the present invention stores several types of probe cards in advance, selects a predetermined probe card corresponding to the wafer to be measured, attaches the selected probe card to the head plate, and In a prober that measures whether each chip on the wafer is good or bad by electrically contacting the attached probe card with the wafer, the housed probe card is attached to a board with a relay board that makes electrical contact with the tester. The selected board is then stored in the head plate and attached to the head plate. Further, it is preferable to set the position between the board and the head plate using guide pins in order to match the arrangement direction of each chip on the wafer with the arrangement direction of the tips of the selected probe cards. Furthermore, the board corresponding to the wafer type is set in the storage shelf in advance, the board code for this storage shelf is memorized, and based on this stored information, the board attached to the head plate and the storage shelf are set. A configuration in which the board is replaced with the next desired board is preferred. The board in the present invention refers to an integral body into which a probe card is inserted into a ring portion and which can be pivoted to a head plate.

[Effect]

When a board with a probe card attached is stored as a single item in multiple storage shelves provided in a storage chamber, the board code for the storage chamber is stored in advance, and a new board code is issued by the host CPU or other means. is specified. At the same time, the old board currently set is unclamped, the gripping and conveying means (handling mechanism) moves to the center of the head plate, grips it, picks it up, moves horizontally, and stores it in a predetermined storage chamber.
Next, the new board designated as described above is gripped by the gripping and conveying means, and then moved to the board insertion part (hole formed in the head plate) formed at the wafer measurement position and lowered. The board is inserted into the insertion section, set at highly accurate X and Y positions, and securely clamped at the insertion position by air, etc., so that the old and new boards can be exchanged automatically and with high precision. be exposed.

【Example】

Next, an embodiment of a wafer prober that enables automatic board replacement according to the present invention will be described with reference to FIGS. 1 to 8. FIG. 1 is a plan view of the main part of the wafer prober, FIG. 2 is a front view of the same as shown in FIG. 1, FIG. Figure 4 is a side view of the main part of Figure 3, Figure 5 is a side view of the board, Figure 6 is a plan view of Figure 5, Figure 7 is an overall operational flowchart when automated, and Figure 8. This is an operation flowchart when replacing the board. In the drawing, 1 is the main stage of the wafer prober, and 2 is the loader stage of the wafer prober. A storage chamber 3 is provided at the rear of the main stage 1, and inside the storage chamber 3 there are a plurality of storage shelves 3a,
3b... is provided. A board 4 is fixed to the head plate 7 by a positioning guide during measurement, and its upper part is electrically connected to the test head 6 by a pogo pin (for example, a contact pin with a spring). 5 and 6, the boards 4 are, from the top, a contact board 4a, a pogo pin board 4b,
It is electrically connected by a probe card 4c. At this time, the positioning between the head plate 7 and the probe card 4c is mechanically performed with high precision by the guide hole 4f and the guide 4g. Also, when the board 4 is set on the storage shelves 3a, 3b..., the guide 4f is attached to the guide pin of each storage shelf.
are positioned together. Reference numeral 5 denotes a mechanical unit used as a gripping and conveying means for the board 4, and as shown in FIGS. 3 and 4, it is composed of an elevating mechanism, a sliding mechanism, and a gripping mechanism for the board hawk 5g. 5
a is a lifting motor, 5b is a lifting screw, 5
5d is a slide motor, 5e is a slide screw, 5f is a slide rail, and 5h is a board gripping cylinder. The gripping and conveying means 5 is a controller 9
By controlling the board 4 set on the head plate 7, the board 4 is placed in a designated storage shelf 3a, 3b...
The storage shelves 3a and 3b are then transported and installed in the
The board 4 installed in... is automatically set in the center of the head plate 7. Reference numeral 8 denotes a motor for controlling the rotation of the test head 6, which is set at the top of the head plate 7 under the control of the controller 9, and is connected to the main stage 1 of the prober.
Control the rotation on the side. The wafers to be measured are stored in each slot of a wafer cassette 11 installed on the loader stage 2, and under the control of the wafer prober controller, the wafers 10 are automatically transferred to the main stage 1 and automatically set. This is an automatic measurement using the board 4 shown in Figure 4. In addition, although the detailed operation of the wafer prober will be omitted, by further automating the needle alignment of the probe card (described later), and in conjunction with the automatic replacement of the board 4 mentioned above, it is possible to handle a wide variety of products. The aim is to build an unmanned system. Next, the operation of the above embodiment will be explained in detail. For example, when measuring a wafer 10 of X type and then measuring a wafer 10 of Y type, it is necessary to replace the board 4 with one corresponding to the Y type. In this example, storage shelves 3a, 3 in the storage room 3 are
A board code is detected for b..., and a board code table for the product type name is filed and set in the controller 9. Upper CPU
Or a new variety name is designated by other means.
At this time, the test head 6 mounted on the main stage 1 of the wafer prober is
The old board (the board 4 currently set on the head plate 7) is then unclamped, the gripping and conveying mechanism 5 moves to the center position of the head plate 7, and the old board 4 is rotated to the left in the figure. is grasped and raised, and is stored in empty storage shelves 3a, 3b, . . . through a horizontal movement process. Next, the gripping and conveying means 5 grips the new board 4 corresponding to the specified product name and moves it to the center position of the head plate 7, and when the new board 4 is inserted, the board 4 is placed horizontally and horizontally on the X and Y rails. Since it is set at a highly accurate X and Y position, the board 4 is clamped with air or the like. Next, the test head 6 mentioned above
descend. This test head 6 has some play in the X, Y, and θ directions, and is
Combine with board 4. Next, when the wafer 10 of type Y is placed on the chuck from the wafer cassette 11 via the transport means and measured, the needle alignment operation of the probe card is automatically performed in advance. In this case, a dummy wafer is used, but this wafer has an orientation rough like a normal measurement wafer, and when a needle mark is made,
Surface treatment is applied to ensure accurate detection. Furthermore, the needle marks on the dummy wafer are saved in a file in the controller of the main stage 1 of the wafer prober, and the location where the needle marks are actually placed can be appropriately controlled. After performing pre-alignment, the dummy wafer is loaded onto the main chuck. Further, the surface level of the dummy wafer is detected by a height sensor. Next, a dummy wafer is placed below the prologue card 4c on the board 4, and set at a position where needle marks will be made. The amount of Z-up when making needle marks is determined by appropriate means such as a needle sensor method. In addition, the position of the needle trace on the dummy wafer is moved under the optical bridge (needle trace inspection mechanism), its exact position is measured, and the probe card 4c is adjusted to the beam position of the optical bridge.
Memorize XY coordinates. At the same time, the inclination of the probe card with respect to the X axis is detected, and the board 4 is rotated by the detected error θ. Make needle marks on the dummy wafer again and check to make sure they are parallel to the X axis. If they are not parallel, repeat this. Next, the dummy wafer is unloaded and returned to its original position. Thereafter, the measurement wafer 10 is loaded into the main chuck, subjected to alignment or other necessary processing, and moved to the position of the probe card 4c for contact. The position of the probe card 4c is accurately measured and stored as described above. Furthermore, if necessary, the needle mark on the pad is checked and automatically corrected in the X and Y directions. After passing through the automatic process as described above, the stylus of the probe card 4c can be brought into contact with the pad on the chip automatically. As described above, even when the product type is changed, the board 4 can be completely automatically replaced, automatic needle alignment can be performed, and wafer testing of the new product type can be automatically continued. ``Effects of the Invention'' As is clear from the above, according to the present invention, it is possible to efficiently replace a board with a probe card and unattended setup, thereby improving productivity in a wafer prober. This greatly contributes to improvement in yield and quality, and it is possible to provide a prober with extremely high utility value. Furthermore, by incorporating a performance board on the tester side into the board and operating it according to the flow shown in Figure 7, not only the operation on the wafer prober side but also the operation on the tester side can be automated, making it possible to perform a wide variety of wafer tests. Since the response becomes unmanned, it has a significant effect on improving productivity.

[Brief explanation of drawings]

The drawings show an embodiment of a wafer prober that enables automatic board replacement according to the present invention; FIG. 1 is a plan view of the main parts of the wafer prober;
Fig. 2 is a front explanatory view of Fig. 1, Fig. 3 is a plan explanatory view of the main part showing a state where the board is replaced via the gripping and conveying means, Fig. 4 is a side view of the main part of Fig. 3, and Fig. 4 is a side view of the main part of Fig. 3. 5
The figure is a side view of the board, Figure 6 is a plan view of Figure 5,
FIG. 7 is a flowchart of the overall operation when automated, and FIG. 8 is a flowchart of the operation when replacing the board. 1...Main stage of the wafer prober, 2...
...Wafer prober loader stage, 3... Storage chamber, 3a, 3b... Board storage shelf, 4... Board, 4a... Performance board or contact board, 4b... Pogo pin board, 4c... Probe card, 4d ...Housing, 4e... Clamp fitting, 4f... Guide hole, 5... Grasping and conveying means, 5a... Lifting motor, 5b... Lifting screw, 5c... Lifting rail, 5d... For sliding Motor, 5e...Slide screw, 5f...Slide rail, 5g...Board hawk, 5h...Gripping cylinder, 6...Test head, 7...Head plate, 8...Test head rotation control motor, 9 ...Controller, 1
0...Wafer, 11...Wafer cassette.

Claims (1)

[Claims] 1. Several types of probe cards are stored in advance, a predetermined probe card corresponding to the wafer to be measured is selected, the selected probe card is attached to the head plate, and the attached probe card is In a prober that measures whether each chip on a wafer is good or bad by electrically contacting the wafer with the wafer, the probe card stored above is stored as a board with an additional relay board that makes electrical contact with the tester, A wafer prober characterized in that the selected board is attached to the head plate. 2. According to claim 1, the position between the board and the head plate is set using guide pins in order to match the arrangement direction of each chip on the wafer with the arrangement direction of the needle tips of the selected probe card. wafer prober. 3. In the above claim 1, a board corresponding to a wafer type is set in advance on a storage shelf, a board code for this storage shelf is stored,
A wafer prober characterized in that the board attached to the head plate is replaced with the next desired board set in the storage shelf based on the stored information.