A method for preventing frost formation in a probe card for low temperature testing and a frost-preventing vertical probe card

Abstract

This invention belongs to the field of probe card low-temperature testing technology, specifically relating to a method for preventing frost formation during probe card low-temperature testing and an anti-frost vertical probe card. It includes a PCB board, a test machine connection mechanism fixed to the upper surface of the PCB board, a locking mechanism fixed under the PCB board, a probe module fixedly connected to the locking mechanism, and an exhaust device mounted on the locking mechanism. The probe module contacts the wafer for testing. The PCB board, locking mechanism, and probe module form a closed space, and the exhaust device extracts and discharges gas from this closed space. This invention uses a miniature device to extract and exhaust gas from the probe module and the local cavity formed between the probe and the wafer, thereby removing moisture containing water molecules to prevent frost formation on the wafer surface. The advantages of this solution are its miniaturization, allowing it to be arranged without affecting the overall structure of the probe card. Furthermore, the power resources of this device can be directly supplied by the probe card PCB, without affecting various wafer testing performance and layouts.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of probe card low-temperature detection, and particularly relates to a probe card low-temperature detection anti-frosting method and an anti-frosting vertical probe card. BACKGROUND

[0002] To ensure that the chip can work stably under extreme conditions, wafer-level testing will be carried out for high and low temperature testing to screen out defective products, and the temperature range is usually from low temperature-70 DEG C to high temperature 150 DEG C. In the process of extreme low temperature testing, the dew point of air is higher than the temperature of wafer surface, and frost will be formed on the wafer surface, which will cause great obstruction of wafer screening and seriously hinder the subsequent process such as chip packaging.

[0003] The test system includes a tester and a probe card connected with the tester, the probe card contacts the wafer, the tester is used to output voltage and current, etc., and the information fed back by the probe card is calculated, and the test result is output. In the prior art, dry compressed air is filled in the test system during the test to prevent frost from being formed on the wafer and the components on the probe card. However, with the increasing number of probe cards and the increasing area of needle implantation, and when the wafer contact is of the pad type, the above method cannot avoid the problem of frost formation on the wafer surface. This is because in the above case, dry gas cannot quickly enter the test area and only stays in the periphery, which cannot replace the water-containing gas previously stored on the probe module and the wafer surface.

[0004] In the prior art, the problem is generally solved by actively blowing gas to the test area through an external gas source, such as Chinese patent CN223679236, which discloses a high and low temperature probe station testing device, which includes a temperature measuring unit, the temperature measuring unit includes a temperature measuring cover and a temperature sensor, the temperature measuring cover covers the recessed cavity of the chuck, and the blowing and sealing design of the upper cover solves the problem of frost formation on the probe card and the wafer during low temperature testing. However, this technical solution changes the structure of the probe card, increases the weight of the product, introduces other alloy structural parts of the probe card and potential other problems. In addition, this technology can only be applied to specific types of probe cards, at least it is not applicable to the vertical probe card proposed in the present application. SUMMARY

[0005] The present application provides a probe card low-temperature detection anti-frosting method and an anti-frosting vertical probe card to solve the technical problem of frost formation on the wafer surface during low temperature testing.

[0006] To solve the above technical problems, the probe card low-temperature detection anti-frost method provided by the application is characterized by the following steps: extracting the gas in the space between the probe module and the PCB board through the exhaust equipment, and making the gas on the wafer surface flow to the space between the probe module and the PCB board, so that the gas with high humidity in the test area is discharged, and the environmental gas with low humidity enters the test area, thereby solving the problem of low-temperature detection frost.

[0007] Optionally, the exhaust equipment is a piezoelectric fan.

[0008] The application further provides an anti-frost vertical probe card, which comprises a PCB board, a tester connecting mechanism fixed on the upper surface of the PCB board, a locking mechanism fixed below the PCB board, a probe module fixedly connected with the locking mechanism, and exhaust equipment arranged on the locking mechanism, wherein the probe module contacts the wafer for testing, the PCB board, the locking mechanism and the probe module form a closed space, and the exhaust equipment extracts the gas in the closed space for discharge.

[0009] Since the PCB board, the locking mechanism and the probe module form a relatively closed space, the dry air outside is difficult to exchange with the closed space automatically, and the gap between the wafer and the probe module is also small, so the gas in the middle area is also difficult to exchange with the air outside when the wafer is large, and the exhaust equipment can drive the wet air in the closed space to move outward, the internal negative pressure makes the wet air on the wafer surface be supplemented to the closed space through the pores on the probe module, and the dry air outside can be further supplemented to the wafer surface and the closed space, so that the dehumidification of the test area is finally realized.

[0010] Optionally, the locking mechanism comprises an outer frame, an opening in the outer frame and at least one exhaust channel arranged on the outer frame, the outer edge of the probe module is fixed with the outer frame, the probe module is located in the opening, and the gas driven by the exhaust equipment is discharged from the closed space through the exhaust channel.

[0011] Optionally, the exhaust equipment is arranged in the exhaust channel.

[0012] Optionally, the exhaust equipment is a piezoelectric fan, and the piezoelectric fan is powered by the PCB board.

[0013] In addition to the piezoelectric fan, a conventional micro-fan with an exhaust function can also be used, but the piezoelectric fan can be made into an ultra-thin structure, which is particularly suitable for the probe card with a layer structure, and the power consumption is low, so that the piezoelectric fan can be directly powered by the PCB board without the need for an external power supply.

[0014] Optionally, the piezoelectric fan is a flat plate type.

[0015] Optionally, the exhaust channel is a groove arranged on the outer frame.

[0016] Optionally, the piezoelectric fan is located at one end of the groove near the enclosed space.

[0017] Optionally, the grooves are arranged in pairs, with the two grooves respectively located at opposite positions on the outer frame.

[0018] Optionally, the outer frame is a rectangular frame, the opening is a concentric rectangular opening, and the exhaust channel is parallel to the frame.

[0019] Optionally, two exhaust channels are provided on the same side of the outer frame, and the two exhaust channels are located at the edge of the opening.

[0020] Optionally, the piezoelectric fan includes a housing, a piezoelectric element disposed within the housing, and a vibrating plate connected to the piezoelectric element. The piezoelectric element is electrically connected to a PCB board and is controlled to start and stop by the PCB board.

[0021] Piezoelectric devices are made of piezoelectric materials. When an AC voltage is applied to them or a DC voltage is applied and then internally converted, the piezoelectric material will periodically elongate and shorten, thereby driving the vibrating plate to vibrate and generate airflow.

[0022] This invention uses a miniature device to extract and vent air from the probe module and the local cavity formed between the probe and the wafer, thereby expelling moisture containing water molecules to prevent frost formation on the wafer surface. The features of this solution are its miniaturization, which allows it to be arranged without affecting the overall structure of the probe card. Furthermore, the power resources of this device can be directly provided by the probe card PCB, without affecting the testing performance and layout of various wafers. Attached Figure Description

[0023] Figure 1 This is an exploded view of a specific embodiment of the anti-frost vertical probe card described in this invention;

[0024] Figure 2 This is an assembly cross-sectional view of a specific embodiment of the anti-frost vertical probe card of the present invention;

[0025] Figure 3 This is a schematic diagram of a specific embodiment of the locking mechanism and piezoelectric fan assembly described in this invention;

[0026] Figure 4 This is a cross-sectional view of a specific embodiment of the piezoelectric fan described in this invention;

[0027] Figure 5 This is a schematic diagram of airflow movement when the exhaust device described in this invention is started.

[0028] As shown in the figure:

[0029] 01-Wafer;

[0030] 10-PCB board, 20-connection mechanism, 30-locking mechanism, 31-outer frame, 32-opening, 331-first exhaust channel, 332-second exhaust channel, 333-third exhaust channel, 334-fourth exhaust channel, 40-probe module, 50-piezoelectric fan, 51-housing, 52-piezoelectric device, 53-vibrating plate, 60-enclosed space. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation and positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] like Figure 1 and 2 As shown, the anti-frost vertical probe card includes a PCB board 10, a test machine connection mechanism 20 fixed on the upper surface of the PCB board 10, a locking mechanism 30 fixed under the PCB board 10, a probe module 40 fixedly connected to the locking mechanism 30, and an exhaust device provided on the locking mechanism 30, wherein the exhaust device is a piezoelectric fan 50.

[0035] like Figure 3As shown, the locking mechanism 30 includes an outer frame 31, an opening 32 inside the outer frame 31, and four exhaust channels disposed on the outer frame 31. The outer edge of the probe module 40 is fixed to the bottom of the outer frame 31, and the probe module 40 is located in the area inside the opening 32. In this embodiment, the exhaust channel 33 is a groove formed on the upper surface of the outer frame 31. It should be noted that a flat piezoelectric fan is used in this embodiment, which can be easily placed in the groove. If it is a fan blade or other type of exhaust device, the exhaust channel can be changed as needed, such as a duct.

[0036] See also Figure 3 The outer frame 31 is designed as a square frame according to the shape of the probe module, and the opening 32 is a concentric square opening. The left side frame is provided with the first exhaust channel 331 and the second exhaust channel 332, and the right side frame is provided with the third exhaust channel 333 and the fourth exhaust channel. The first exhaust channel 331 and the third exhaust channel 333 are paired and located in opposite positions on the outer frame 31. The second exhaust channel 332 and the fourth exhaust channel 334 are paired and located in opposite positions on the outer frame 31. The first exhaust channel 331 and the second exhaust channel 332 are located at the two edges of the opening 32, and the third exhaust channel 333 and the fourth exhaust channel 334 are located at the two edges of the opening 32. The piezoelectric fan 50 is embedded in the corresponding exhaust channel and is close to one end of the internal opening 32 area.

[0037] It should be noted that if the probe is circular or other shapes, the outer frame can be changed to a circle or other shapes accordingly. As long as the gas in the exhaust channel with the exhaust device is outside the gas exhaust area within the opening area, it is considered part of our invention concept. The structure and position can also be adjusted accordingly as needed.

[0038] like Figure 4 As shown, the piezoelectric fan 50 is a flat plate type, which includes a housing 51, a piezoelectric element 52 disposed in the housing 51, and a vibrating plate 53 connected to the piezoelectric element 52. The piezoelectric element 52 is electrically connected to the PCB board 10 and is controlled to start and stop by the PCB board 10.

[0039] like Figure 5As shown, the airflow during the exhaust system operation is as follows: The probe module 40 contacts the wafer 01 for low-temperature testing. The PCB board 10, the locking mechanism 30, and the probe module 40 form a closed space 60. It should be noted that the PCB board 10 and the probe module 40 are generally connected by a space converter, meaning the space converter is located within the closed space 60. However, the space converter does not completely fill the closed space; gas exists within it and can flow within this area. The piezoelectric fan 50 draws gas from the closed space 60 and discharges it, creating a relative negative pressure state in the closed space 60. The humid air on the surface of the wafer 01 (blue arrow) flows into the closed space 60 through gaps in the probe module 40 and the locking mechanism 30, such as probe hole gaps and mating gaps. Meanwhile, dry air from the environment (red arrow) flows from the periphery towards the test area, ultimately replacing the humid and cold gas in the test area and preventing frost formation.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preventing frosting at low temperatures using a probe card, characterized in that, By extracting and expelling the gas between the probe module and the PCB board through the exhaust device, the gas on the wafer surface flows into the space between the probe module and the PCB board. As the gas with higher humidity in the test area is discharged from the test area, the ambient gas with lower humidity can enter the test area, thus solving the problem of frosting during low-temperature testing.

2. The method for preventing frosting during low-temperature detection using a probe card according to claim 1, characterized in that, The exhaust device is a piezoelectric fan.

3. A vertical probe card for preventing frost formation, characterized in that, The device includes a PCB board, a test machine connection mechanism fixed on the upper surface of the PCB board, a locking mechanism fixed under the PCB board, a probe module fixedly connected to the locking mechanism, and an exhaust device installed on the locking mechanism. The probe module contacts the wafer for testing. The PCB board, the locking mechanism, and the probe module form a closed space. The exhaust device extracts gas from the closed space and discharges it.

4. The anti-frost vertical probe card according to claim 3, characterized in that, The locking mechanism includes an outer frame, an opening inside the outer frame, and at least one exhaust channel disposed on the outer frame. The outer edge of the probe module is fixed to the outer frame, and the probe module is located in the area inside the opening. The gas driven by the exhaust device is discharged from the enclosed space through the exhaust channel.

5. The anti-frost vertical probe card according to claim 4, characterized in that, The exhaust equipment is installed inside the exhaust channel.

6. The anti-frost vertical probe card according to claim 5, characterized in that, The exhaust device is a piezoelectric fan, which is powered by a PCB board.

7. The anti-frost vertical probe card according to claim 6, characterized in that, The piezoelectric fan is a flat plate type.

8. The anti-frost vertical probe card according to claim 7, characterized in that, The exhaust channel is a groove formed on the outer frame.

9. The anti-frost vertical probe card according to claim 8, characterized in that, The piezoelectric fan is located at one end of the groove near the enclosed space.

10. The anti-frost vertical probe card according to claim 8, characterized in that, The outer frame is a rectangular frame with concentric rectangular openings. The exhaust channels are parallel to the frame. Two exhaust channels are provided on the same side of the outer frame, and the two exhaust channels are located at the edge of the opening.

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