TWI390211B - Vertical probe card - Google Patents

Description

Vertical probe card

The invention relates to the technical field of probe cards, in particular to a vertical probe card structure using a needle probe.

Probe cards for semiconductor wafers are typically tested, primarily using a variety of probes in contact with the semiconductor wafer. Among all the components of each set of probe cards, the number of probes is the largest, and it occupies most of the cost of the probe card. The types of probes currently used include cantilever probes, spring probes, and vertical bending probes.

As semiconductor wafers are getting smaller and smaller, the size of the probes needs to be reduced simultaneously. The reduced probe must still be properly resilient so that the probe does not cause damage to the wafer when it comes into contact with the wafer. In addition, the probe itself must also enable good transmission of electrical signals. Therefore, the smaller the probe cost, the higher the cost. In view of this, the inventors considered how to design a set of vertical probe cards, which effectively reduced the cost of the probe, but still did not reduce the test and contact performance required for the probe card.

SUMMARY OF THE INVENTION A primary object of the present invention is to provide a vertical probe card that utilizes a conductive adhesive for wafer testing and a needle probe as a medium for wafer contact and electrical transmission in a test operation. The probe is in the shape of a thin needle, which is in contact with the wafer to be tested. The conductive adhesive for the wafer test is responsible for the elastic buffering of the probe contact. The probe used in this way has a low cost and is connected with the integral probe card. The manufacturing cost is also reduced, making the product more competitive in the market.

A secondary object of the present invention is to provide a vertical probe card, which mainly eliminates the disadvantage that a conventional partial probe (for example, a cantilever probe) needs to be welded with a wire. The present invention can utilize the locking and sequential assembly methods of each component. Ensure the electrical contact of the components, make the production assembly more convenient, and the product yield will also increase.

To achieve the above object, the present invention includes a circuit board, a conductive paste for wafer testing, a fixed module, and a plurality of probes. The conductive paste for wafer testing is longitudinally distributed with a plurality of adjacent but non-contacting electrical conductors having a small wire diameter and a compressive elasticity. The fixing module is coupled to the underside of the circuit board, and the plurality of probes are disposed at the fixed module. The position of the conductive adhesive for the wafer test is limited between the bottom of the circuit board and the upper surface of the area where the fixed module is fixed. The top surface of the probe is in contact with the conductive paste for testing the wafer. The electrical conductor of the conductive paste for testing the wafer is electrically connected to the circuit board, thus forming the vertical probe card of the present invention.

The detailed structure of the present invention and its connection relationship will be described in conjunction with the following figures, so that those skilled in the art can implement the present invention after studying the present specification.

Please refer to the first and second figures, which are a bottom view and a partial cross-sectional view of a partial area of the vertical probe card of the present invention. The probe test card 100 of the present invention is mainly composed of a circuit board 1, a conductive paste for wafer testing 2, a fixed module 3, and a plurality of probes 4.

A detailed description of the structure of each component will be given below. As shown in the third figure. The probe 4 has a fine needle shape, and is an enlarged schematic view in the figure. Actually, the probe 4 has a size of only 0.14 to 0.32 mm. The probe 4 is composed of a contact pin 41 and a latching member 42. The outer diameter of the latching member 42 is larger than the contact pin 41. The latching member 42 is located above the contact pin 41. . This probe 4 does not have spring-like elasticity.

As shown in the second figure, the fixing module 3 is coupled to the lower surface of the circuit board 1. Both of them are screwed (not shown in the figure), so that the fixing module 3 does not move arbitrarily. The fixing module 3 is responsible for fixing and limiting the position of the conductive adhesive 2 for testing the wafer and the plurality of probes 4 under the circuit board 1. As shown in the fourth figure, the fixed module 3 has a plurality of probe holes 31 extending through the plurality of pin holes 312 and pin holes 311 having different apertures. The aperture of the card aperture 312 is larger than the pinhole 311 and is located above the pinhole 311. The apertures of the pinhole 311 and the latching hole 312 correspond to the contact pin 41 and the latching member 42 of the probe 4, respectively. Although the probe 4 is placed in the corresponding probe 31 during assembly, the position is not completely fixed, and the probe 4 can still move upward by a slight distance. The longitudinal dimension of the probe hole 31 is smaller than the length of the probe 4. When the probe 4 is assembled to the fixed module 3, the bottom end of the contact pin 41 of the probe 4 and the top end of the latching member 42 extend out of the fixed mold. Group 3 has a probe hole 31 outside.

The top surface of the fixed area of the fixed module 3 is formed with a recessed receiving space 32. In the second figure, only a part of the receiving space 32 is shown. The accommodating space 32 is mainly used as the place where the conductive paste 2 for the wafer test is disposed. As shown in the first figure, the range of the conductive paste 2 for the wafer test is indicated by a broken line, and is also the range of the accommodating space 32. The conductive paste 2 for wafer testing is limited between the lower surface of the circuit board 1 and the upper surface of the region where the fixed probe 3 is fixed to the fixed module 3. When assembled, the wafer test conductive paste 2 is in close contact with the lower surface of the circuit board 1. The top surface of the latching member 42 of the plurality of probes 4 is in close contact with the lower surface of the wafer test conductive paste 2, so that The position of the conductive paste 2 for the wafer test is fixed.

The conductive adhesive 2 for wafer testing is a currently existing product, and the English name is IC Testing Inter-Connector. As shown in FIGS. 5A and 5B, the conductive paste 2 for wafer testing mainly has a plurality of adjacent conductors 21 which are adjacent to each other but not in contact with each other in the longitudinal direction of the material, and an insulator 22 is formed around the conductor 21. In the figure, it is presented in an enlarged magnification. In fact, the diameter of the conductor 21 is less than 0.025 mm, and the spacing between the adjacent two conductors 21 is also only 0.1 to 0.05 mm. Since the plurality of electric conductors 21 are extremely thin and are pressed against the electric conductor 21 in the vertical direction, the electric conductor 21 has a slight bending elasticity. The present invention utilizes the elasticity of the conductor 21 of the conductive paste 2 for wafer testing, so that the probe 4 also has elasticity when it comes into contact with the wafer to be tested.

The circuit board 1 is located at the uppermost position of the overall structure. The upper and lower surfaces of the circuit board 1 have associated lines, and the lines on the lower surface of the circuit board 1 must match the positions of the plurality of probes 4. The upper surface of the circuit board 1 is connected to the test device for related testing. In the present invention, the conductive paste 2 for wafer testing is used as a medium for the circuit board 1 to be in contact with the probe 4. Since the conductor 21 of the conductive paste 2 for wafer testing is extremely fine and dense, each probe 4 has 4 ~8 electrical conductors 21 are in contact with each other, and the electrical conductors 21 are in contact with the metal pads opposite to the lower surface of the circuit board 1 for electrical signal transmission, thereby ensuring that the vertical probe card operates normally.

As shown in the second figure, when assembled, the plurality of probes 4 are first mounted in the probe holes 31 at the relative positions of the fixed module 3, and the conductive adhesive 2 for testing the wafer is placed in the fixed module 3. The accommodating space 32 is at this time, and the conductive paste 2 for wafer testing is at the top surface of the top member 42 of the plurality of probes 4. Then, the fixing module 3 is screwed to the lower position of the circuit board 1 so that the two cannot move. As a result, the position of the conductive paste 2 for the wafer test is limited between the circuit board 1 and the fixed module 3, and the top surface of the conductive paste 2 for the test wafer is in close contact with the lower surface of the circuit board 1. The lower surface of the conductive paste 2 for wafer testing is in close contact with the plurality of probes 4. Since the dense conductive conductors 21 are distributed on the conductive paste 2 for wafer testing, each probe 4 has at least a plurality of electrical conductors 21 in contact therewith, and the other end of the electrical conductors 21 is in contact with the circuit board 1 Ensure that the signal transmission from board 1 to probe 4 is unobstructed and there is no short circuit during wafer testing.

In the above-mentioned practical example, the probe 4 is needle-like, and the outer shape is rounded needle-shaped, but it is not limited thereto. As shown in the sixth figure, it is another embodiment of the probe 4A of the present invention. In the perspective view, the probe 4A is still constituted by the contact pin 41A and the latch member 42A, but has a shape of a three-dimensional quadrangular needle, and the latch member 42A is flatter than the contact pin 41A.

In summary, the vertical probe card of the present invention utilizes a plurality of needle-shaped probes and the conductive adhesive for the wafer test as a medium for contact and signal transmission between the circuit board and the wafer to be tested. The use of a needle-like probe can greatly reduce the cost of making a probe card, reducing the cost of the probe card without affecting the necessary characteristics required for the probe card. Moreover, the probe card is a test work area formed by a vertical probe. The smaller the area of the test work area can be, which is beneficial to the trend of smaller and smaller chips, and it is also convenient for the designer to adopt the array on the circuit board. More test work areas are formed to improve the efficiency of the test.

However, the above description is only for the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the equivalent variation and modification of the patent application scope of the present invention should still belong to the present invention patent. Within the scope of coverage.

A. . . Probe card

1. . . Circuit board

2. . . Conductive adhesive for wafer testing

twenty one. . . Electrical conductor

twenty two. . . Insulator

3. . . Fixed module

31. . . Probe hole

311. . . Pinhole

312. . . Card hole

32. . . Housing space

4. . . Probe

41. . . Contact

42. . . Card assembly

4A. . . Probe

41A. . . Contact

42A. . . Card assembly

The first figure is a bottom view of a partial area of the probe card of the present invention;

The second figure is a schematic cross-sectional view of the AA plane of the first figure, in which the conductor of the conductive paste for the wafer test is not drawn in this figure;

The third figure is an enlarged perspective view of the probe of the present invention;

The fourth figure is an exploded view of the probe and the fixed module of the present invention;

Figure 5A is a partially enlarged schematic view showing a cross section of a conductive paste for wafer testing used in the present invention;

Figure 5B is a partially enlarged schematic view showing the longitudinal section of the conductive paste for wafer testing used in the present invention;

The sixth drawing is an enlarged perspective view of the second probe of the present invention.

100. . . Probe card

1. . . Circuit board

2. . . Conductive adhesive for wafer testing

3. . . Fixed module

31. . . Positioning hole

32. . . Housing space

4. . . Probe

41. . . Contact pin

42. . . Card assembly

Claims (7)

A vertical probe card includes a circuit board, a conductive adhesive for wafer testing, a plurality of probes, and a fixed module, wherein: the conductive paste for testing the wafer is longitudinally distributed with a plurality of adjacent but non-contacting electrical conductors An insulator is formed around the conductor, the conductor has a small wire diameter and has elasticity that can be compressed; the fixing module is fixedly fixed under the circuit board; the plurality of probes are needle-like and are disposed on the fixed module The position of the conductive adhesive for the wafer test is limited between the lower surface of the circuit board and the upper surface of the area where the fixing module fixes the probe, and the top surface of the probe is in contact with the conductive adhesive for testing the wafer. The probe is electrically connected to the circuit board through the electrical conductor of the conductive paste for the wafer test. The vertical probe card of claim 1, wherein the plurality of probes are disposed at the fixed module, but the probe still retains an offset that can move up slightly. The vertical probe card of claim 1, wherein the fixing module has a plurality of penetrating probe holes, the probe is mounted in the probe hole, and the longitudinal dimension of the probe hole Because of the length of the probe, the top end and the bottom end of the probe extend out of the probe hole of the fixed module. The vertical probe card of claim 1, wherein the probe is needle-shaped, and is composed of a latching member and a contact pin. The maximum diameter of the latching member is larger than that of the contact pin. The member is located above the contact pin. The vertical probe card of claim 4, wherein the probe is cylindrical-like. The vertical probe card of claim 4, wherein the probe is a stereoscopic polygonal needle. The vertical probe card of claim 4, wherein the fixing module has a plurality of penetrating probe holes, wherein the probe holes are formed by a pinhole having a different aperture and a latching hole. The aperture of the card hole is larger than the pinhole, and the position is also above the pinhole. The latching member and the contact pin of the probe are respectively located in the latching hole and the pinhole, and the contact pin bottom of the probe is Both the end and the top of the clip protrude beyond the probe hole of the fixed module.