Probe card probe cleaning abrasive paper and preparation method thereof

Abstract

The invention relates to the technical field of probe card cleaning, in particular to probe card probe cleaning abrasive paper and a preparation method thereof.The probe card probe cleaning abrasive paper comprises a base material layer, a buffer layer and an abrasive material layer which are sequentially stacked; the base material layer is made of flexible polyether-ether-ketone, and the thickness range of the base material layer is 40-60 microns; the buffer layer is made of foamed silica gel, and the thickness range of the buffer layer is 50-100 microns; the grinding material layer is prepared by mixing grinding material particles and addition type silicone rubber, and the thickness range is 170-230 microns; wherein the abrasive particles comprise silicon carbide particles, and the particle size range of the silicon carbide particles is 1-5 [mu] m; by taking the mass of the addition type silicone rubber as a reference, the mass ratio of the abrasive particles is 20-200%. By the adoption of the probe cleaning abrasive paper, the probe tip can be effectively cleaned, and the probe tip can be prevented from being damaged in the probe cleaning process as much as possible.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of probe card cleaning, in particular to a probe card cleaning sandpaper and a preparation method thereof. BACKGROUND

[0002] As a core interface component in the semiconductor chip testing process, the contact state of the probe and the chip pad directly determines the testing accuracy. In the long-term testing process, the probe surface is easy to attach contaminants such as solder residue, oxide layer, dust and scratch particles generated during the testing process. These contaminants can cause poor contact between the probe and the chip pad, resulting in problems such as signal attenuation, high impedance, contact short circuit or leakage current, ultimately leading to misjudgment of the test results, significantly reducing the wafer test yield and increasing the manufacturing cost. Therefore, regular cleaning of the probe is an indispensable maintenance link in the semiconductor testing process.

[0003] To solve the problem of probe contamination, the industry has formed various cleaning methods for MEMS probe cards, mainly including the following three types: first, manual wiping with ordinary sandpaper to remove surface contaminants through physical friction; second, using a clean cloth to dip cleaning agents such as isopropyl alcohol for manual wiping, combining chemical dissolution and physical wiping to clean the probe surface; third, using a laser cleaning device to achieve high-temperature stripping of contaminants using laser energy. In addition, some scenes also use needle cleaning paper or a brush with alcohol for cleaning, but this is still an extension of physical wiping or chemical assisted cleaning.

[0004] The above existing cleaning methods all have significant technical defects and cannot meet the comprehensive needs of semiconductor testing for cleaning effect, probe protection and operation convenience: for the manual wiping method with ordinary sandpaper, the abrasive particles of the sandpaper are uneven and have high hardness, which can easily cause the probe tip to wear, deform, or even damage the probe surface coating during cleaning, shortening the service life of the probe card; for the wiping method with a clean cloth dipped in cleaning agents, it cannot effectively remove stubborn oxide layers and solder residues, and the liquid cleaning agent may penetrate into the internal circuit of the probe card, causing a short circuit risk; for the laser cleaning device, its purchase and operation cost is high, the operation process is complex, and professional maintenance is required, which cannot meet the actual needs of rapid maintenance in the testing site.

[0005] Therefore, how to solve the above-mentioned problems of the prior art has become the research subject of the present application. SUMMARY

[0006] The purpose of the present application is to provide a probe card cleaning sandpaper and a preparation method thereof.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present application is:

[0008] The probe card cleaning sandpaper is used for a 2D MEMS probe card with flat needle tips, a needle tip diameter of 25-50 microns and a needle tip spacing of 50-100 microns, and the probe card cleaning sandpaper comprises a substrate layer, a buffer layer and an abrasive layer which are sequentially laminated (connected);

[0009] The substrate layer is made of flexible polyether ether ketone and has a thickness ranging from 40 to 60 microns;

[0010] The buffer layer is made of foamed silica gel and has a thickness ranging from 50 to 100 microns;

[0011] The abrasive layer is made of abrasive particles and addition type silicone rubber and has a thickness ranging from 170 to 230 microns;

[0012] The abrasive particles include silicon carbide particles with a particle size ranging from 1 to 5 microns, and the mass percentage of the abrasive particles in the addition type silicone rubber is 20% to 200%.

[0013] Preferably, the abrasive particles are composed of silicon carbide particles.

[0014] Preferably, the lengths and widths of the substrate layer, the buffer layer and the abrasive layer are consistent.

[0015] The substrate layer, the buffer layer and the abrasive layer form a layered structure to achieve different effects.

[0016] For the substrate layer, flexible polyether ether ketone (PEEK) with a thickness of 40-60 microns is used, so as to have good tensile strength (>90Mpa). Compared with the traditional substrate layer material of the probe card cleaning sandpaper which is made of flexible polyimide, the substrate layer in the present application has higher toughness and better fatigue resistance, so as to ensure that the sandpaper is not easy to break when repeatedly bent, and to facilitate the adaptation of the probe arrangement of different probe cards. The substrate layer in the present application also has a wider chemical resistance range, and is suitable for more complex cleaning environments.

[0017] For the buffer layer, which is arranged on the upper surface of the substrate layer, it can buffer the pressure when the abrasive layer contacts the probe through elastic deformation, preventing the probe from being damaged by rigid impact. The buffer layer uses a foamed silica gel with a thickness of 50-100 microns. Compared with the traditional buffer layer using foamed polyurethane, the Shore A hardness of the buffer layer in the present application is 20-50, which can be accurately controlled, and the elastic performance is better, with a rebound attenuation of <95% after 10,000 repeated compressions, so the buffer performance is better. In addition, the specific buffer layer in the present application has a uniform distribution of closed / semi-closed structures, which can more efficiently disperse the local stress of the probe tip, splitting the force received by one point to other closed / semi-closed structures of the buffer layer, greatly reducing the stress intensity of each point; at the same time, the pore walls of the closed / semi-closed structures are continuous and uniform, and the local pressure applied by the probe tip will be transmitted through the pore walls like a "network", facilitating the diffusion of force from the contact point to a larger structure area, and better reducing the risk of probe tip damage caused by stress concentration.

[0018] For the abrasive layer, which is arranged on the upper surface of the buffer layer, it is made of abrasive particles mixed with addition type silicone rubber. The abrasive particles are silicon carbide particles, and the mass ratio of the abrasive particles to the addition type silicone rubber is 20%-200% (preferably 100%). Compared with the abrasive layer in the traditional needle cleaning sandpaper, which is made of silicon carbide particles mixed with a resin binder, the abrasive layer in the present application has lower hardness, more uniform distribution of silicon carbide particles, and tighter combination of silicon carbide particles and addition type silicone rubber. These optimizations can reduce the damage rate of the probe tip and more comprehensively and uniformly clean the probe tip. Based on the specific selection of silicon carbide particles and addition type silicone rubber, and the specific ratio setting of the two, the cleaning effect on the probe card and the damage rate of the probe tip can be guaranteed.

[0019] In summary, the needle cleaning sandpaper in the present application can effectively clean the probe tip and minimize the damage to the probe tip during cleaning, without the problems of being unable to effectively remove stubborn oxide layers and solder residues in the background technology, the possibility of liquid cleaning agent penetrating into the internal circuit of the probe card, and high cost.

[0020] It should be noted that the needle cleaning sandpaper in the present application can be tailored according to the array width of the cleaned MEMS probe card or other high-precision probe card, and is more widely applicable. When using the needle cleaning sandpaper, the tailored needle cleaning sandpaper can be attached to a silicon wafer, and a shaping machine is used to clean and shape the probe card to be cleaned. The cleaning direction and frequency can be adjusted according to the required cleaning degree.

[0021] Further, the particle size of the silicon carbide particles is selected from any one of 1 μm, 3 μm and 5 μm, or a combination of any two or more of the above values, which can ensure the cleaning effect on the probe tip.

[0022] It should be noted that the probe tip diameter of the sandpaper suitable for cleaning the probe in the present application is in the range of 25-50 μm, and the tip spacing is 50-100 μm. Based on this, the suitable particle size of silicon carbide is 1-5 μm, and the ratio between the tip diameter and the particle size of silicon carbide is 25:1-10:1. For silicon carbide particles, the main purpose is to clean the dirt on the tip. If the particle size of silicon carbide is too large, it can easily cause the tip to break or deform, or the tip spacing to be too small, causing short circuit during testing. If the particle size of silicon carbide is too small, it can be difficult to clean stubborn dirt on the tip, and multiple cleanings are required. From the aspects of applicability and safety, the ratio between the tip diameter and the particle size of silicon carbide is 25:1-10:1, which is a reasonable interval. The smaller the tip diameter, the more it tends to be 25:1, and small particles are used to protect the tip from being damaged. The larger the tip diameter, the more it tends to be 10:1, and large particles are used to achieve better cleaning effect while protecting the tip. In addition, if the tip spacing is small, such as less than twice the tip diameter, the particle size of silicon carbide can be appropriately reduced to prevent the particles from pressing the tip and causing short circuit during testing, and the content of silicon carbide in the abrasive layer can be appropriately increased to improve the cleaning effect.

[0023] Further, the addition type silicone rubber is obtained by mixing vinyl-terminated polysiloxane and hydrogen-containing silicone oil, and the mass ratio of the two is 1:1.

[0024] The addition type silicone rubber is obtained by mixing A glue (vinyl-terminated polysiloxane) and B glue (hydrogen-containing silicone oil) at a mass ratio of 1:1. Compared with ordinary condensation type silicone rubber, the mixture of A and B glue has no reaction byproducts, which can make the silicon carbide particles more uniformly distributed, and make the silicone rubber tightly wrap the silicon carbide particles to prevent the abrasive particles from falling off during the cleaning process, improve the cleaning effect, and improve the cleaning efficiency.

[0025] The more uniform distribution of silicon carbide particles can not only make the pressure applied by the tip uniformly distributed on multiple abrasive particles, but also reduce the risk of tip damage in cooperation with the structure of the buffer layer. On the other hand, it can also have stable grinding and cleaning effect every time the tip contacts the abrasive layer, making the cleaning of the probe card more thorough and efficient.

[0026] The specific addition type silicone rubber is configured to have no weak layer between the contact interface of the abrasive layer and the buffer layer, thereby having better adhesion.

[0027] The specific addition type silicone rubber used in the abrasive layer and the foamed silica gel used in the buffer layer belong to the same system, which can better prevent the abrasive layer and the buffer layer from gradually separating during needle cleaning, thereby prolonging the service life of the sandpaper.

[0028] Compared with the mixture of A glue and B glue in a mass ratio of 1:2 or 2:1, the addition type silicone rubber obtained by mixing in a mass ratio of 1:1 has appropriate viscosity and better flowability, which can ensure the quality of the sandpaper. For example, the addition type silicone rubber obtained by mixing in a mass ratio of 1:1 can be coated by a scraper coater within 45 minutes after mixing, and the surface of the product (sandpaper) is smooth and flat. However, the mixed silicone rubber obtained by mixing in other mass ratios has too large viscosity, and the surface of the sandpaper product obtained by coating with a scraper coater is uneven and has many damages.

[0029] A preparation method of a probe card needle cleaning sandpaper, which is used to prepare the probe card needle cleaning sandpaper in any of the above embodiments, and the preparation method comprises the following steps:

[0030] Step one, a flexible polyether ether ketone film with a thickness ranging from 40 to 60 μm is prepared by using flexible polyether ether ketone, to obtain a base material layer;

[0031] Step two, a foamed silica gel slurry is prepared;

[0032] Step three, the foamed silica gel slurry is uniformly coated on the surface of the base material layer;

[0033] Step four, the base material layer is sent into an oven for foaming and curing, to obtain a buffer layer formed on the surface of the base material layer and composed of foamed silica gel, and the thickness of the buffer layer ranges from 50 to 100 μm;

[0034] Step five, an addition type silicone rubber is prepared, and the addition type silicone rubber is mixed with abrasive particles to form a preliminary slurry after defoaming; the abrasive particles include silicon carbide particles with a particle size ranging from 1 to 5 μm, and the mass of the abrasive particles is 20% to 200% of the mass of the addition type silicone rubber;

[0035] Step six, the preliminary slurry is uniformly coated on the surface of the buffer layer;

[0036] Step seven, the buffer layer is sent into an oven for curing, to obtain an abrasive layer (with a thickness ranging from 170 to 230 μm) formed on the surface of the buffer layer.

[0037] It can be understood that step one and step two can be implemented together, and the step of preparing the addition type silicone rubber is also the same, so the above steps do not have to be implemented sequentially.

[0038] In step seven, the base material layer and the buffer layer are sent into the oven together.

[0039] The above preparation method can produce a specific probe card cleaning sandpaper. This specific probe card cleaning sandpaper can effectively clean the probe tip and minimize the damage to the probe tip during the cleaning process. It does not have the problems of the prior art, such as the inability to effectively remove stubborn oxide layers and solder residues, the possibility of liquid cleaning agents penetrating into the internal circuit of the probe card, and high cost.

[0040] A further technical solution involves pretreating the substrate layer before uniformly coating the foamed silicone slurry onto the substrate layer surface to improve its surface tension, including the following steps:

[0041] S1, Clean substrate layer;

[0042] S2. Perform low-temperature plasma activation treatment on the cleaned substrate layer.

[0043] The method for cleaning the substrate layer is standard and will not be described in detail here.

[0044] During the low-temperature plasma activation process, the working gas can be oxygen with a flow rate of 80 sccm, the discharge power can be 200 W, the working pressure can be 50 Pa, low vacuum conditions can be used, and the processing time can be 40 s. This low-temperature plasma activation process creates a nano- to micron-scale uneven structure on the substrate surface and introduces polar functional groups such as carboxyl and hydroxyl groups. This increases the surface tension of the substrate layer, facilitating a more uniform distribution of the buffer layer on the substrate surface and improving stress distribution. This enhances the overall structural stability of the sandpaper, reduces the risk of delamination, and extends the lifespan of the sandpaper.

[0045] A further technical solution involves low-temperature plasma activation treatment using oxygen as the treatment gas, with the following parameters: pressure of 50 Pa under low vacuum, treatment power of 200 W, oxygen flow rate of 80 sccm, and treatment time of 40 s. These parameter settings effectively ensure increased surface tension of the substrate layer, facilitating a more uniform distribution of the buffer layer on the substrate surface and improving stress distribution. This enhances the overall structural stability of the sandpaper, reduces the risk of delamination, and extends the lifespan of the sandpaper.

[0046] A further technical solution involves obtaining addition-type silicone rubber by mixing vinyl-terminated polysiloxane with hydrogen-containing silicone oil in a mass ratio of 1:1.

[0047] Addition-type silicone rubber is obtained by mixing A (vinyl-terminated polysiloxane) and B (hydrogen-containing silicone oil) in a 1:1 (mass ratio). Compared with ordinary condensation-type silicone rubber, the mixture of A and B has no reactive byproducts, which can make the silicon carbide particles more evenly distributed and make the silicone rubber firmly wrap the silicon carbide particles, preventing the abrasive particles from falling off during the cleaning process and causing secondary pollution, thus improving the cleaning effect and improving the cleaning efficiency.

[0048] In a further technical solution, in step six, a doctor blade coating machine is used to uniformly coat the prepared slurry onto the surface of the buffer layer, and the time difference between the end time of coating the prepared slurry and the completion time of preparation of the addition-cured silicone rubber is within 45 minutes.

[0049] Compared to mixing A and B components in mass ratios of 1:2 and 2:1, a 1:1 mixture yields addition-cure silicone rubber with suitable viscosity and better flowability, ensuring sandpaper quality. The 1:1 mixture can be coated using a doctor blade coater within 45 minutes of mixing, producing a smooth and even sandpaper surface. In contrast, other mass ratios result in excessively high viscosity, leading to uneven surfaces and frequent damage when coated with a doctor blade coater.

[0050] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence, nor are they intended to limit this case; they are merely used to distinguish components or operations described using the same technical terms.

[0051] The terms "connection" or "positioning" as used in this article can refer to two or more components or devices making direct physical contact with each other, or making indirect physical contact with each other, or to two or more components or devices operating or moving with each other.

[0052] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.

[0053] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of the art, the subject matter, and the specific context. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing this case.

[0054] The terms “front,” “back,” “up,” “down,” “left,” and “right” used in this article are directional terms. In this case, they are only used to describe the positional relationship between the structures and are not intended to limit the specific direction of the protection scheme or its actual implementation.

[0055] The working principle and advantages of this invention are as follows:

[0056] For the substrate layer, a flexible polyetheretherketone (PEEK) with a thickness of 40-60 micrometers is used, resulting in good tensile strength (>90 MPa). Compared with the flexible polyimide substrate layer material of traditional cleaning sandpaper, the substrate layer in this application has higher toughness and better fatigue resistance, ensuring that the sandpaper is not easily broken when repeatedly bent, making it easy to adapt to the probe arrangement of different probe cards. The substrate layer in this application also has a wider chemical tolerance range, adapting to more complex cleaning environments.

[0057] The buffer layer, located on the upper surface of the substrate layer, buffers the pressure when the abrasive layer contacts the probe through elastic deformation, preventing damage to the probe from rigid impacts. The buffer layer uses 50-100 micrometers thick foamed silicone. Compared to traditional buffer layers using polyurethane foam, the buffer layer in this application has a Shore A hardness of 20-50, which can be precisely controlled, and superior elasticity, with a rebound attenuation of <95% after 10,000 repeated compressions, thus providing better buffering performance. Furthermore, because the specific buffer layer in this application has a uniformly distributed closed-cell / semi-closed-cell structure, it can more efficiently disperse the local stress on the probe tip, distributing the force on one point to other closed-cell / semi-closed-cell structures in the buffer layer, significantly reducing the stress intensity at each point. Simultaneously, the pore walls of the closed-cell / semi-closed-cell structure are continuous and uniform, allowing the local pressure applied by the probe tip to be transmitted through the pore walls like a "network," facilitating the diffusion of force from the contact point to a larger structural area, further reducing the risk of probe tip damage due to stress concentration.

[0058] The abrasive layer, located on the upper surface of the buffer layer, is composed of a mixture of abrasive particles and addition-cure silicone rubber. The abrasive particles are silicon carbide particles, and their mass percentage relative to the addition-cure silicone rubber is 20%-200%. Compared to the abrasive layer made by mixing silicon carbide particles with resin binder in traditional cleaning abrasive paper, the abrasive layer made by mixing silicon carbide particles and addition-cure silicone rubber in this application has lower hardness, more uniform distribution of silicon carbide particles, and a tighter bond with the addition-cure silicone rubber. These optimizations can reduce the tip damage rate of the probe card and allow for more comprehensive and uniform tip cleaning. Based on the specific selection of silicon carbide particles and addition-cure silicone rubber, and the specific ratio setting of the two, the cleaning effect on the probe card and the reduction of the probe tip damage rate can be guaranteed.

[0059] In summary, the cleaning sandpaper described in this application can effectively clean the probe tips and minimize damage to the probe tips during the cleaning process. It does not have the problems of the prior art, such as the inability to effectively remove stubborn oxide layers and solder residues, the possibility of liquid cleaning agents penetrating into the internal circuitry of the probe card, and high costs. Attached Figure Description

[0060] Appendix Figure 1This is a schematic diagram of the probe card cleaning sandpaper structure according to an embodiment of the present invention;

[0061] Appendix Figure 2 This is a flowchart of the probe card cleaning sandpaper preparation method according to an embodiment of the present invention.

[0062] In the above figures: 1. Substrate layer; 2. Buffer layer; 3. Abrasive layer. Detailed Implementation

[0063] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0064] Example: The present invention will be clearly described below with illustrations and detailed description. Any person skilled in the art who understands the examples of the present invention can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0065] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.

[0066] See appendix Figure 1 A probe card cleaning abrasive paper, for 2D MEMS probe cards with flat tips, tip diameter of 25-50μm and tip spacing of 50-100μm, the probe card cleaning abrasive paper includes a substrate layer 1, a buffer layer 2 and an abrasive layer 3 stacked (connected) in sequence.

[0067] The substrate layer 1 is made of flexible polyetheretherketone and has a thickness ranging from 40 to 60 μm.

[0068] The buffer layer 2 is made of foamed silicone and has a thickness ranging from 50 to 100 μm.

[0069] The abrasive layer 3 is made of a mixture of abrasive particles and addition-curing silicone rubber and has a thickness ranging from 170 to 230 μm.

[0070] The abrasive particles include silicon carbide particles with a particle size ranging from 1 to 5 μm; based on the mass of the addition-type silicone rubber, the mass percentage of the abrasive particles is 20% to 200%.

[0071] Preferably, the abrasive particles are composed of silicon carbide particles.

[0072] Preferably, the overall thickness of the cleaning sandpaper is 280-360μm, and the thickness difference at different points in the sandpaper does not exceed 30μm.

[0073] Preferably, the length and width of the substrate layer 1, the buffer layer 2 and the abrasive layer 3 are the same.

[0074] The substrate layer 1, buffer layer 2 and abrasive layer 3 form a layered structure to achieve different effects.

[0075] For the substrate layer 1, a flexible polyetheretherketone (PEEK) with a thickness of 40-60 micrometers is used, which provides good tensile strength (>90 MPa). Compared with the flexible polyimide material used for the substrate layer 1 of traditional cleaning sandpaper, the substrate layer 1 in this embodiment has higher toughness and better fatigue resistance, ensuring that the sandpaper is not easily broken when repeatedly bent, making it easy to adapt to the probe arrangement of different probe cards. The substrate layer 1 in this embodiment also has a wider chemical tolerance range, adapting to more complex cleaning environments.

[0076] The buffer layer 2, located on the upper surface of the substrate layer 1, can buffer the pressure when the abrasive layer 3 contacts the probe through elastic deformation, preventing the probe from being damaged by rigid impact. The buffer layer 2 uses foamed silicone with a thickness of 50-100 micrometers. Compared with the traditional buffer layer 2 using foamed polyurethane, the buffer layer 2 in this embodiment has a Shore A hardness of 20-50, which can be precisely controlled, and its elasticity is superior, with a rebound attenuation of <95% after 10,000 repeated compressions, thus providing better buffering performance. Furthermore, because the specific buffer layer 2 in this embodiment has a uniformly distributed closed-cell / semi-closed-cell structure, it can more efficiently disperse the local stress on the probe tip, distributing the force on one point to other closed-cell / semi-closed-cell structures in the buffer layer 2, significantly reducing the stress intensity at each point. Simultaneously, the pore walls of the closed-cell / semi-closed-cell structure are continuous and uniform, allowing the local pressure applied by the probe tip to be transmitted through the pore walls like a "network," facilitating the diffusion of force from the contact point to a larger structural area, further reducing the risk of probe tip damage due to stress concentration.

[0077] The abrasive layer 3, located on the upper surface of the buffer layer 2, is made of a mixture of abrasive particles and addition-cure silicone rubber. The abrasive particles are silicon carbide particles, and the mass ratio of the abrasive particles to the addition-cure silicone rubber is 20%-200% (preferably 100%). Compared with the abrasive layer made by mixing silicon carbide particles with resin binder in traditional cleaning abrasive paper, the abrasive layer 3 made of silicon carbide particles and addition-cure silicone rubber in this embodiment has lower hardness, more uniform distribution of silicon carbide particles, and a tighter bond with addition-cure silicone rubber. These optimizations can reduce the tip damage rate of the probe card and allow for more comprehensive and uniform cleaning of the tips. Based on the specific selection of silicon carbide particles and addition-cure silicone rubber, and the specific ratio setting of the two, the cleaning effect on the probe card and the reduction of the probe tip damage rate can be guaranteed.

[0078] In summary, the cleaning sandpaper used in this embodiment can effectively clean the probe tip and minimize damage to the probe tip during the cleaning process. It does not have the problems of the prior art, such as the inability to effectively remove stubborn oxide layers and solder residues, the possibility of liquid cleaning agents penetrating into the internal circuitry of the probe card, and high cost.

[0079] It should be noted that the cleaning abrasive paper in this embodiment can be cut to size according to the array width of the MEMS probe card or other high-precision probe card to be cleaned, thus having a wider range of applications. When using this cleaning abrasive paper, the cut abrasive paper can be attached to the silicon wafer, and the probe card to be cleaned can be cleaned and shaped using a shaping machine. The cleaning direction and number of cleaning passes can be adjusted according to the required level of cleanliness.

[0080] In this embodiment, the particle size of the silicon carbide particles is selected from any one of 1μm, 3μm and 5μm, or from any combination of two or more of the above values. The setting of this particle size or particle size range can ensure the cleaning effect for such fine structures as probe tips.

[0081] It should be noted that the probe tip diameter range for the cleaning sandpaper in this embodiment is 25-50 μm, and the tip spacing is 50-100 μm. Based on this, the suitable silicon carbide particle size should be 1-5 μm, and the ratio between the tip diameter and the silicon carbide particle size should be 25:1-10:1. The main purpose of the silicon carbide particles is to clean dirt and debris from the probe tip. If the silicon carbide particles are too large, it can easily cause the probe tip to break or deform, or compress the probe tip, resulting in an excessively small tip spacing, which may cause a short circuit during testing. If the silicon carbide particles are too small, it may be difficult to clean stubborn dirt from the probe tip, requiring multiple cleanings. From the perspectives of applicability and safety, a ratio of 25:1 to 10:1 between the tip diameter and the silicon carbide particle size is considered reasonable. Smaller tip diameters tend to favor a 25:1 ratio, using smaller particles to protect the tip from damage. Larger tip diameters tend to favor a 10:1 ratio, using larger particles for better cleaning, achieving a good cleaning effect while protecting the tip. Additionally, if the tip spacing is small, such as less than twice the tip diameter, the silicon carbide particle size can be appropriately reduced to prevent particles from compressing the tip and causing a short circuit during testing. Simultaneously, the silicon carbide particle content in the abrasive layer 3 can be appropriately increased to improve the cleaning effect.

[0082] In this embodiment, the addition-type silicone rubber is obtained by mixing vinyl-terminated polysiloxane and hydrogen-containing silicone oil, and the mass ratio of the two is 1:1.

[0083] Addition-type silicone rubber is obtained by mixing A (vinyl-terminated polysiloxane) and B (hydrogen-containing silicone oil) in a 1:1 (mass ratio). Compared with ordinary condensation-type silicone rubber, the mixture of A and B has no reactive byproducts, which can make the silicon carbide particles more evenly distributed and make the silicone rubber firmly wrap the silicon carbide particles, preventing the abrasive particles from falling off during the cleaning process and causing secondary pollution, thus improving the cleaning effect and improving the cleaning efficiency.

[0084] The more uniform distribution of silicon carbide particles allows the pressure applied by the needle tip to be evenly distributed across multiple abrasive particles, working synergistically with the structure of the buffer layer 2 to reduce the risk of needle tip damage. On the other hand, it ensures that each contact of the needle tip with the abrasive layer 3 has a stable grinding and cleaning effect, resulting in a more thorough and efficient cleaning of the probe card.

[0085] The specific addition-cure silicone rubber configuration ensures that there are no weak layers between the abrasive layer 3 and the buffer layer 2, resulting in better adhesion. The absence of weak layers is explained as follows: the buffer layer 2 and the abrasive layer 3 are tightly bonded, and there is no insufficient adhesion in the contact area (both foamed silicone and addition-cure silicone rubber inherently possess a certain degree of adhesion). Delamination and peeling are extremely rare, and there are no structural defects such as gaps or bubbles between them, forming a continuous and uniform interface.

[0086] The specific addition-cured silicone rubber used in the abrasive layer 3 and the foamed silicone rubber used in the buffer layer 2 belong to the same system, which can better prevent the abrasive layer 3 and the buffer layer 2 from gradually separating during the cleaning process and extend the service life of the sandpaper.

[0087] Compared to mixing A and B components in mass ratios of 1:2 or 2:1, a 1:1 mixture yields addition-cure silicone rubber with suitable viscosity and better flowability, ensuring sandpaper quality. For example, addition-cure silicone rubber mixed in a 1:1 ratio can be coated using a doctor blade coater within 45 minutes of mixing, resulting in a smooth and flat sandpaper surface. In contrast, silicone rubber mixtures obtained in other mass ratios have excessively high viscosity, leading to uneven surfaces and frequent damage in sandpaper products coated with a doctor blade coater.

[0088] See appendix Figure 2 A method for preparing probe card cleaning sandpaper, used to prepare the probe card cleaning sandpaper in any of the above embodiments, the preparation method includes the following steps:

[0089] Step 1: A flexible polyetheretherketone (PEEK) film with a thickness ranging from 40 to 60 μm is prepared using flexible PEEK to obtain substrate layer 1;

[0090] Step 2: Prepare the foamed silicone slurry;

[0091] Step 3: Apply the foamed silicone slurry evenly to the surface of substrate layer 1;

[0092] Step 4: The substrate layer 1 is placed in an oven for foaming and curing to obtain a buffer layer 2 formed on the surface of the substrate layer 1 and made of foamed silicone. The thickness of the buffer layer 2 is 50-100μm.

[0093] Step 5: Prepare addition-cure silicone rubber, mix the addition-cure silicone rubber with abrasive particles and degas to form a preparative slurry; the abrasive particles include silicon carbide particles with a particle size range of 1-5 μm, and the mass of the abrasive particles is 20%-200% of the mass of the addition-cure silicone rubber.

[0094] Step 6: Apply the prepared slurry evenly to the surface of buffer layer 2;

[0095] Step 7: Place the buffer layer 2 into an oven for curing to obtain the abrasive layer 3 (thickness range of 170-230μm) formed on the surface of the buffer layer 2.

[0096] It is understandable that steps one and two can be performed together, including the step of preparing addition-cure silicone rubber; therefore, the above steps do not necessarily have to be performed sequentially.

[0097] In step seven, the substrate layer 1 and the buffer layer 2 are sent into the oven together.

[0098] The above preparation method can produce a specific probe card cleaning sandpaper. This specific probe card cleaning sandpaper can effectively clean the probe tip and minimize the damage to the probe tip during the cleaning process. It does not have the problems of the prior art, such as the inability to effectively remove stubborn oxide layers and solder residues, the possibility of liquid cleaning agents penetrating into the internal circuit of the probe card, and high cost.

[0099] In this embodiment, before uniformly coating the foamed silicone slurry onto the surface of the substrate layer 1, the substrate layer 1 is pretreated to improve its surface tension, including the following steps:

[0100] S1, Clean substrate layer 1;

[0101] S2. Perform low-temperature plasma activation treatment on the cleaned substrate layer 1.

[0102] The method for cleaning substrate layer 1 is standard and will not be described in detail here.

[0103] During the low-temperature plasma activation process, the working gas can be oxygen with a flow rate of 80 sccm, the discharge power can be 200 W, the working pressure can be 50 Pa, low vacuum conditions can be used, and the processing time can be 40 s. The low-temperature plasma activation process creates a nano- to micron-scale uneven structure on the surface of substrate layer 1 and introduces polar functional groups such as carboxyl and hydroxyl groups, thereby increasing the surface tension of substrate layer 1. This facilitates a more uniform distribution of buffer layer 2 on the surface of substrate layer 1 and improves stress distribution, enhancing the overall structural stability of the sandpaper, reducing the risk of delamination, and extending the service life of the sandpaper.

[0104] In this embodiment, the low-temperature plasma activation treatment uses oxygen as the treatment gas, and the treatment parameters are as follows: pressure of 50 Pa under low vacuum, treatment power of 200 W, oxygen flow rate of 80 sccm, and treatment time of 40 s. These parameter settings effectively ensure an increase in the surface tension of the substrate layer 1, which facilitates a more uniform distribution of the buffer layer 2 on the surface of the substrate layer 1 and improves stress distribution. This enhances the overall structural stability of the sandpaper, reduces the risk of delamination, and extends the service life of the sandpaper.

[0105] In this embodiment, the addition-type silicone rubber is obtained by mixing vinyl-terminated polysiloxane and hydrogen-containing silicone oil, and the mass ratio of the two is 1:1.

[0106] Addition-type silicone rubber is obtained by mixing A (vinyl-terminated polysiloxane) and B (hydrogen-containing silicone oil) in a 1:1 (mass ratio). Compared with ordinary condensation-type silicone rubber, the mixture of A and B has no reactive byproducts, which can make the silicon carbide particles more evenly distributed and make the silicone rubber firmly wrap the silicon carbide particles, preventing the abrasive particles from falling off during the cleaning process and causing secondary pollution, thus improving the cleaning effect and improving the cleaning efficiency.

[0107] In this embodiment, in step six, a doctor blade coating machine is used to uniformly coat the prepared slurry onto the surface of the buffer layer 2, and the time difference between the end time of coating the prepared slurry and the completion time of the addition-cured silicone rubber preparation is within 45 minutes.

[0108] Compared to mixing A and B components in mass ratios of 1:2 and 2:1, a 1:1 mixture yields addition-cure silicone rubber with suitable viscosity and better flowability, ensuring sandpaper quality. The 1:1 mixture can be coated using a doctor blade coater within 45 minutes of mixing, producing a smooth and even sandpaper surface. In contrast, other mass ratios result in excessively high viscosity, leading to uneven surfaces and frequent damage when coated with a doctor blade coater.

[0109] The following specific embodiments are provided for illustration:

[0110] Example 1

[0111] Using flexible polyetheretherketone (PEEK) as the substrate layer, foamed silicone as the buffer layer, and silicon carbide particles mixed with addition-cure silicone rubber to form an abrasive layer, a special sandpaper for cleaning semiconductor probe cards is formed. The specific setup and preparation method of this sandpaper are as follows:

[0112] Substrate layer: A flexible polyetheretherketone film with a thickness of 50 micrometers and a tensile strength of 110 MPa is used;

[0113] Buffer layer: The cleaned substrate layer is activated by low-temperature plasma (oxygen is selected and the substrate layer is treated for 40 seconds under low vacuum conditions of 200W power and 50Pa pressure with a gas flow rate of 80sccm). The substrate layer is cleaned, etched (to obtain a nano- to micron-level uneven structure on the surface), and chemically modified (carboxyl groups, hydroxyl groups and other polar functional groups are introduced). Then, the foamed silicone slurry obtained by degassing by a planetary degassing machine is evenly coated on the surface of the substrate layer with a scraper. Then, it is sent into a segmented oven for foaming and curing to obtain a buffer layer with a thickness of 100 microns made of foamed silicone.

[0114] Abrasive layer: Mix A glue (see above description), B glue (see above description), and 3-micron silicon carbide particles in a mass ratio of 1:1:2. Mix and degas in a planetary degassing machine to form a slurry. Apply the slurry evenly to the buffer layer with a scraper, and then cure in an oven to form an abrasive layer with a thickness of 200 microns.

[0115] Sandpaper size: 110mm × 110mm;

[0116] Specifications of the 2D MEMS probe card to be cleaned: flat tip, tip diameter of 40μm, and tip spacing of 90μm; the tip diameter of this probe card is 40μm. To ensure that the tip is not damaged or deformed and that the cleaning effect is good, silicon carbide particles with a particle size of 3μm are selected as abrasive; the ratio of tip diameter to silicon carbide particle size is preferably 25:1-10:1, and is set to 13.3:1 in this embodiment 1;

[0117] The cleaning abrasive paper of this embodiment was applied to the silicon wafer, and the MEMS probe card to be cleaned was cleaned and shaped using a shaping machine. This process was repeated 20,000 times in four directions. The probe tip was observed with a high-powered optical microscope and no obvious dirt or deformation was found. The contact resistance of the cleaned probe card was tested, and the average contact resistance of the probes in the same group was <0.28Ω, with a standard deviation of 0.011Ω.

[0118] The following table shows the results of testing traditional sandpaper under the same testing conditions: Example 1 Conventional clean sandpaper Probe tip No significant dirt, deformation Sandpaper had significant shedding, some probes deformed Average contact resistance <0.28 ohms <0.98 ohms Standard deviation of contact resistance 0.011 Ω 0.17 Ω

[0119] It can be seen that the cleaning power of the cleaning needle sandpaper in this embodiment 1 is greater than that of traditional cleaning needle sandpaper.

[0120] Example 2

[0121] Using flexible polyetheretherketone (PEEK) as the substrate layer, foamed silicone as the buffer layer, and silicon carbide particles mixed with addition-cure silicone rubber to form an abrasive layer, a special sandpaper for cleaning semiconductor probe cards is formed. The specific setup and preparation method of this sandpaper are as follows:

[0122] Substrate layer: A flexible polyetheretherketone film with a thickness of 60 micrometers and a tensile strength of 130 MPa is used;

[0123] Buffer layer: The cleaned substrate layer is activated by low-temperature plasma (oxygen is selected and the substrate layer is treated for 40 seconds under low vacuum conditions of 200W power and 50Pa pressure with a gas flow rate of 80sccm). The substrate layer is cleaned, etched (to obtain a nano- to micron-level uneven structure on the surface), and chemically modified (carboxyl groups, hydroxyl groups and other polar functional groups are introduced). Then, the foamed silicone slurry obtained by degassing by a planetary degassing machine is evenly coated on the surface of the substrate layer with a scraper. Then, it is sent into a segmented oven for foaming and curing to obtain a buffer layer with a thickness of 100 microns made of foamed silicone.

[0124] Abrasive layer: Mix A glue (see above description), B glue (see above description), and 1-micron silicon carbide particles in a mass ratio of 1:1:3. Mix and degas in a planetary degassing machine to form a slurry. Apply the slurry evenly to the buffer layer with a scraper and then cure in an oven to form an abrasive layer with a thickness of 200 microns.

[0125] Sandpaper size: 80mm × 110mm;

[0126] Specifications of the 2D MEMS probe card to be cleaned: flat tip, tip diameter 30μm, tip spacing 50μm; the probe card diameter is 30μm. According to the tip diameter to silicon carbide particle size ratio of 25:1-10:1, the particle size of the silicon carbide particles used can be 1.2μm. However, the tip spacing is 50μm, which is less than 60μm. To ensure the cleaning effect and to prevent damage or deformation of the tip during the cleaning process, the silicon carbide particle size is appropriately reduced (set to 1μm), and the proportion of silicon carbide particles is increased (1:1:3).

[0127] The cleaning abrasive paper of this embodiment was applied to the silicon wafer, and the MEMS probe card to be cleaned was cleaned and shaped using a shaping machine. This process was repeated 20,000 times in four directions. The probe tip was observed with a high-powered optical microscope and no obvious dirt or deformation was found. The contact resistance of the cleaned probe card was tested, and the average contact resistance of the probes in the same group was <0.36Ω, with a standard deviation of 0.028Ω.

[0128] The following table shows the results of testing traditional sandpaper under the same testing conditions: Example 2 Conventional clean sandpaper Probe tip No significant dirt, deformation Sandpaper had significant shedding, some probes deformed Average contact resistance <0.36 ohms <1.3Ω Standard deviation of contact resistance 0.028 Ω 0.25 Ω

[0129] Based on Examples 1 and 2, it can be concluded that using the cleaning sandpaper in this example in conjunction with existing devices to clean and shape MEMS probe cards can ensure the cleaning effect on the probe cards and reduce the damage rate of probe tips.

[0130] It should be noted that average contact resistance and standard deviation of contact resistance are important indicators for measuring the cleaning ability of cleaning abrasive paper for probe cards: a lower average contact resistance indicates better contact and less contamination residue on the probe tips; the standard deviation of contact resistance reflects the consistency of contact resistance among probes in the same group, and a smaller value indicates better probe cleaning uniformity. The average contact resistance and standard deviation of contact resistance after cleaning the probe cards with the cleaning abrasive paper in Examples 1 and 2 are much lower than those of traditional cleaning abrasive paper.

[0131] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A probe card cleaning sandpaper, characterized by: The 2D MEMS probe card with flat needle tip, needle tip diameter of 25-50μm and needle tip spacing of 50-100μm, the probe card needle sandpaper includes sequentially stacked base material layer (1), buffer layer (2) and abrasive layer (3); The base material layer (1) is made of flexible polyether ether ketone and has a thickness range of 40-60μm; The buffer layer (2) is made of foamed silica gel and has a thickness range of 50-100μm; The abrasive layer (3) is made of abrasive particles and addition type silicone rubber and has a thickness range of 170-230μm; The abrasive particles include silicon carbide particles with a particle size range of 1-5μm; the mass fraction of the abrasive particles is 20%-200% based on the mass of the addition type silicone rubber.

2. A probe card cleaning sandpaper according to claim 1, wherein: The particle size of the silicon carbide particles is selected from any one of 1μm, 3μm and 5μm, or a combination of any two or more of the above values.

3. The probe card cleaning sandpaper of claim 1, wherein: The addition type silicone rubber is obtained by mixing vinyl-terminated polysiloxane and hydrogen-containing silicone oil, and the mass ratio of the two is 1:

1.

4. A method of making a probe card cleaning sandpaper, characterized by: A method for preparing the probe card needle sandpaper of any one of claims 1-3, comprising the following steps: Step one, a flexible polyether ether ketone film with a thickness range of 40-60μm is made of flexible polyether ether ketone, and a base material layer (1) is obtained; Step two, foamed silica gel slurry is prepared; Step three, the foamed silica gel slurry is uniformly coated on the surface of the base material layer (1); Step four, the base material layer (1) is sent into an oven for foaming and curing to obtain a buffer layer (2) formed on the surface of the base material layer (1) and composed of foamed silica gel, and the thickness of the buffer layer (2) is in the range of 50-100μm; Step five, addition type silicone rubber is prepared, and the addition type silicone rubber is mixed with abrasive particles to form a preliminary slurry; the abrasive particles include silicon carbide particles with a particle size range of 1-5μm, and the mass of the abrasive particles is 20%-200% of the mass of the addition type silicone rubber; Step six, the preliminary slurry is uniformly coated on the surface of the buffer layer (2); Step seven, the buffer layer (2) is sent into an oven for curing to obtain an abrasive layer (3) formed on the surface of the buffer layer (2).

5. The method for preparing a probe card cleaning sandpaper according to claim 4, characterized in that: Before the foamed silica gel slurry is uniformly coated on the surface of the base material layer (1), the base material layer (1) is pretreated to improve the surface tension of the base material layer (1), including the following steps: S1, clean the base material layer (1); S2, low temperature plasma activation treatment is performed on the cleaned base material layer (1).

6. The method of claim 5, wherein the abrasive paper is prepared by the steps of: providing a paper sheet; applying a first layer of abrasive particles to the paper sheet; applying a second layer of abrasive particles to the paper sheet; and applying a third layer of abrasive particles to the paper sheet. The low temperature plasma activation treatment uses oxygen as the treatment gas, and the treatment parameters meet: the pressure is 50Pa under low vacuum environment, the treatment power is 200W, the oxygen flow is 80sccm, and the treatment time is 40s.

7. The method of claim 4, wherein the abrasive paper is prepared by the steps of: providing a paper sheet; applying a first layer of abrasive particles to the paper sheet; applying a second layer of abrasive particles to the paper sheet; and applying a third layer of abrasive particles to the paper sheet. The addition type silicone rubber is obtained by mixing vinyl-terminated polysiloxane and hydrogen-containing silicone oil, and the mass ratio of the two is 1:

1.

8. The method of claim 7, wherein the abrasive paper is prepared by the steps of: providing a paper sheet; applying a first layer of abrasive particles to the paper sheet; applying a second layer of abrasive particles to the paper sheet; and applying a third layer of abrasive particles to the paper sheet. In step six, the preliminary slurry is uniformly coated on the surface of the buffer layer (2) using a doctor blade coater, and the time difference between the end time point of coating the preliminary slurry and the completion time point of preparing the addition type silicone rubber is within 45min.

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