Probe cleaning sheet

Abstract

To provide a probe cleaning sheet capable of exhibiting sufficient cleaning performance for a probe in a high-temperature inspection temperature range.SOLUTION: A probe cleaning sheet having a cleaning layer for removing a foreign matter adhering to a tip of a probe, includes a foamed resin layer of a polyimide resin having resistance to a temperature exceeding 200 degrees, and an abrasive layer formed on the foamed resin layer and made of abrasive particles and an epoxy resin.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a probe cleaning sheet used to remove foreign matter adhering to probe needles of a probe card used in electrical property testing, and more particularly to a probe cleaning sheet that can be used at high temperatures. [Background technology]

[0002] Probe needles of a probe card attached to a tester are brought into contact with a semiconductor device (chip) and test signals are applied and detected through the probes to test the electrical characteristics of the semiconductor device.

[0003] Generally, probes are made of hard materials such as tungsten and beryllium. On the other hand, electrode pads are made of relatively soft materials such as aluminum. When the probe is brought into contact with the electrode pad, foreign matter such as aluminum oxide on the surface of the electrode pad adheres to the tip of the probe (the tip and the side near the tip), causing poor electrical connection between the probe and the pad and reducing the accuracy of the test. In addition, if a large foreign matter adheres to the probe, adjacent probes may short-circuit and destroy the chip. For this reason, when testing the electrode pads of a chip, the tip of the probe is cleaned to remove any foreign matter that has adhered.

[0004] A probe cleaning sheet, which is a base sheet having a cleaning layer formed on the surface thereof, is used to clean the probe tip. In cleaning using this probe cleaning sheet, the probe cleaning sheet is attached to the surface of an inspection table, and the tip of the probe is inserted into the cleaning layer (also called the polishing layer) through the surface thereof and then pulled out, thereby removing foreign matter adhering to the probe tip.

[0005] As such a probe cleaning sheet, a cleaning member made of an elastic material such as silicone resin or urethane resin mixed with abrasive particles (hard particles made of aluminum oxide, silicon carbide, diamond, etc.) has been proposed (see, for example, Patent Document 1). Also, a cleaning member has been proposed in which a foreign matter removal film not containing abrasive particles is provided on a polishing member containing abrasive particles, and the foreign matter is effectively wiped off with the foreign matter removal film when the probe tip is pulled out (see, for example, Patent Document 2). Still further, a cleaning member has been proposed in which an elastic polishing layer is formed on the surface of a substrate having a roughened surface, the polishing layer is recessed by the pressing force of the probe tip, and the abrasive particles that have entered between the recessed portion and the rough surface clean the probe tip (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 7-244074 [Patent Document 2] Japanese Patent Application Publication No. 11-87438 [Patent Document 3] JP 2004-271389 A Summary of the Invention [Problem to be solved by the invention]

[0007] Nowadays, the use of power semiconductor devices that handle voltages of several hundred volts is expanding. When power semiconductors are in use, the temperature exceeds 200 degrees. Therefore, there is a demand for devices that can provide sufficient cleaning performance in the same temperature range as the power semiconductors are in use.

[0008] The silicone resins and urethane resins used in conventional probe cleaning sheets exhibit effective properties at relatively low temperatures, but have problems with heat resistance and cannot be used at high operating temperatures exceeding 200 degrees.

[0009] Furthermore, in this operating temperature range, depending on the configuration of the cleaning member, the tip of the probe may be significantly chipped and worn away after multiple cleanings, shortening the life of the probe, and this wear may cause errors in electrical characteristic testing.

[0010] An object of the present invention is to provide a probe cleaning sheet that can exhibit sufficient cleaning performance for a probe in a high inspection temperature range. [Means for solving the problem]

[0011] In order to achieve the above object, the present invention provides a probe cleaning sheet having a cleaning layer for removing foreign matter adhering to the tip of a probe, the cleaning layer including a foamed resin layer of polyimide resin and an abrasive layer formed on the foamed resin layer and comprising abrasive particles and a binder resin.

[0012] A probe cleaning sheet with such a cleaning layer can efficiently remove foreign matter adhering to the tip of a probe during electrical property testing at high temperatures exceeding 200° C., and can retain the removed foreign matter within the cleaning layer. When the cleaning layer is pierced and pulled out, the sheet has good adhesion and sliding properties with the tip of the probe, enhancing the cleaning effect.

[0013] The abrasive layer is preferably 10 μm. The abrasive particles are preferably in the range of 0.01 μm to 13 μm.

[0014] The abrasive particles may be one or a mixture of two or more of diamond, white alumina, silicon carbide, boron carbide, cerium oxide, zirconium oxide, chromium oxide, iron oxide, titanium oxide, silicon dioxide, manganese dioxide, manganese trioxide, zirconium silicate, barium carbonate, glass, boron nitride, and titanium nitride.

[0015] The binder resin may be selected from the group consisting of epoxy resins, polyimide resins, and silicone resins.

[0016] An adhesive layer may be provided on the foamed resin layer opposite the polishing layer, and the adhesive layer may be a heat-resistant double-sided tape attached with a silicone adhesive. According to such a probe cleaning material, instead of the base sheet, the cleaning layer can be formed directly on the metal plate of the inspection table of the inspection device. Also, the cleaning layer may be formed directly on the surface of the reclaimed silicon wafer. Effect of the Invention

[0017] According to the present invention, it is possible to provide a probe cleaning sheet that can sufficiently perform cleaning to remove foreign matter adhering to the probe tip in a wide temperature range, from low to high, in the environment in which the chip is used, and that also reduces wear on the probe. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic partial cross-sectional view of a first embodiment of a probe cleaning sheet according to the present invention. [Figure 2(a)] FIG. 2(a) is an optical photograph of a partial plane of the probe cleaning sheet according to the present invention taken with an observation device (optical microscope). [Figure 2(b)] FIG. 2(b) is an optical photograph of a partial cross section of a probe cleaning sheet according to the present invention. [Diagram 3] FIG. 3 is a schematic partial cross-sectional view of the probe cleaning device. [Figure 4] FIG. 4 is a schematic partial cross-sectional view of a second embodiment of a probe cleaning sheet according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0020] First Embodiment The probe cleaning sheet according to the present invention will be described with reference to FIG. 1, which shows a schematic partial cross-sectional view thereof.

[0021] 1, the probe cleaning sheet 10 is composed of a base sheet 25 and a cleaning layer 20 formed on the surface of the base sheet 25. The cleaning layer 20 is formed of an elastic material 21 and an abrasive layer 22 formed thereon. The cleaning layer 20 and the base sheet 25 of this embodiment will be described below.

[0022] (1) Cleaning layer a) Elastic material (foam) As shown in Fig. 1, the elastic material 21 constituting the cleaning layer is made of a polyimide foam on a base sheet 25. The polyimide resin has heat resistance in the temperature range of the semiconductor device (chip) usage environment (temperatures above 200°C), and the foam of the polyimide resin is not simply a form of scattered air bubbles, but is formed in the form of piled-up thin flakes, as shown in Fig. 2(a) and Fig. 2(b). This foam is a stable material whose physical properties do not change in the environment of chip electrical characteristic testing.

[0023] b) Polishing layer The surface of the elastic material (foam) of the cleaning layer 20 has randomly exposed flakes (FIG. 2(a)), on which an abrasive layer 22 is formed. The abrasive layer is composed of abrasive particles and a binder resin.

[0024] As the abrasive particles, for example, one or more selected from diamond, white alumina, silicon carbide, boron carbide, cerium oxide, zirconium oxide, chromium oxide, iron oxide, titanium oxide, silicon dioxide, manganese dioxide, manganese trioxide, zirconium silicate, barium carbonate, glass, boron nitride, and titanium nitride can be used.

[0025] The binder resin can be selected from the group consisting of epoxy resins, polyimide resins, and silicone resins.

[0026] The average particle size of the abrasive particles is preferably in the range of 0.03 μm to 130 μm, and more preferably in the range of 0.5 μm to 4.0 μm.

[0027] The cleaning layer 20 is required to have a thickness that allows the probe needle to be inserted and removed to remove any attached matter from the needle tip, and is preferably in the range of, for example, 50 to 1000 μm. With a thickness in this range, the probe needle can be inserted into the cleaning layer, and damage to the probe can be suppressed.

[0028] The thickness of the polishing layer is preferably about 10 μm. Although there is no limit to this thickness, if it is too thin, the cleaning effect decreases, and if it is too thick, the needle may be damaged.

[0029] Furthermore, when forming the cleaning layer 20 of the present invention, a colorant can be added to the elastic material 21. In the probe cleaning device, the probe cleaning sheet is placed on a stage of the probe cleaning device, and the distance between the cleaning sheet surface and the tip of the probe is adjusted to an appropriate value by autofocusing with a detector that utilizes a laser beam or the like, but adding a colorant can increase the light reflection efficiency and ensure accurate alignment between the cleaning sheet surface and the probe tip.

[0030] (2) Base sheet The base sheet 25 of the present invention is preferably made of a material that exhibits minimal changes in physical properties in the temperature range of electrical characteristic tests that correspond to the high-temperature environment in which the chip is used, similar to the cleaning layer 20. In addition, a material is selected that does not cause wrinkles, peeling, or the like due to differences in thermal expansion coefficients between the base sheet 25 and the cleaning layer 20 or thermal deformation.

[0031] Specifically, the material of the base sheet 25 is a heat-resistant resin such as polyimide (PI), silicone rubber, polyethylene naphthalate (PEN), polyether ether ketone (PEEK), etc. In order to fix the probe cleaning sheet 10 to the probe cleaning device, an adhesive layer is provided on the lower side of the base sheet 25. A silicone adhesive that can withstand high temperatures is used for this adhesive layer.

[0032] Also, without using the above-mentioned base sheet 25, the cleaning layer 20 may be formed directly on a metal plate having a shape that can be fixed to the stage of a probe cleaning device, on a reclaimed silicon wafer, or the like. For example, the cleaning layer 20 may be formed in advance on a metal plate having the same shape as the inspection silicon wafer, or on a reclaimed silicon wafer, using a cleaning material that will form the cleaning layer 20, and then attached to the stage of the probe cleaning device by applying a double-sided adhesive film or a pressure sensitive adhesive. Also, depending on the stage, it may be possible to vacuum-adsorb it. <Second embodiment> Next, a second embodiment of the probe cleaning sheet according to the present invention will be described with reference to a partial cross-sectional schematic view of Fig. 4. Note that parts with the same names as those in the first embodiment are designated by the same reference numerals.

[0033] The probe cleaning sheet 10 shown in FIG. 4 is a probe cleaning sheet in the form of a product, which further comprises an adhesive layer 28 on the back side of the base sheet 25 in the probe cleaning sheet of the first embodiment, and a release sheet 26 covering this adhesive layer 28.

[0034] In general, the cleaning sheet 10 used in a probe inspection device has a release sheet (release film) 26 having an adhesive layer 28 provided on the back side of a base sheet 25 in order to fix the cleaning sheet 10 to the inspection device. The release sheet 26 is peeled off from the surface of the adhesive layer 28 and, as will be described later, is attached via the adhesive layer 28 onto a stage 33 of a probe cleaning device 30 shown in FIG. 3.

[0035] The adhesive layer 28 is preferably made of a silicone adhesive that can withstand high temperatures in the electrical property testing environment. Depending on the material of the stage of the probe cleaning device, the adhesive layer 28 may have a two-layer structure with an acrylic adhesive to maintain adhesive strength. The release sheet 26 is peeled off from the base sheet 25, and the probe cleaning sheet 10 is fixed to the probe cleaning device.

[0036] The adhesive layer and release sheet may be a heat-resistant double-sided tape using a silicone adhesive.

[0037] Alternatively, the adhesive layer 28 may not be provided on the probe cleaning sheet 10, and the base sheet 25 may be vacuum-adsorbed onto the table.

[0038] The cleaning layer 20 can also be formed directly on a metal plate having a shape that can be fixed to the table of a probe cleaning device, or on the surface of a reclaimed silicon wafer. In this way, problems such as wrinkles and peeling that occur in the cleaning layer 20 due to differences in thermal expansion coefficients with the base sheet can be avoided even at high temperatures.

[0039] Furthermore, a protective sheet (e.g., a resin film such as PET or PP) for preventing adhesion of dust in the air may be attached onto the cleaning layer 20. The release sheet 26 and the protective sheet are peeled off when in use, so they do not need to be particularly heat resistant.

[0040] (Cleaning method) A probe cleaning method using the probe cleaning sheet 10 according to the present invention will be exemplified below.

[0041] Probe cleaning can be performed manually, but is generally performed using a probe cleaning device 30 shown in Fig. 4. The probe cleaning device 30 shown in Fig. 3 is a device that removes foreign matter attached to the tip of a probe 32 of a probe card 31, and includes a stage 33 that moves relatively to the probe card 31, a probe cleaning sheet 34 set on the stage 33, and an autofocus mechanism (not shown) that moves the stage 33 relatively to the probe 32.

[0042] The autofocus mechanism positions the probe 32 relative to the stage 33. Thereafter, the probe 32 is pierced into the cleaning sheet 34 with a certain pressure, and the abrasive particles in the cleaning layer scrape off any adhering matter (foreign matter) on the tip of the probe, and the cleaning layer wipes off the scraped off foreign matter when the probe is pulled out. This cycle removes the adhering foreign matter without damaging the tip of the probe 32. The amount of piercing of the needle tip of the probe 32 in this probe cleaning differs depending on the type of probe, but is usually around 20 μm to 100 μm.

[0043] As the number of times or duration of use of a probe card used in chip performance testing increases, foreign matter adheres to the tip of the probe placed on the probe card. The probe with the foreign matter adhered to its tip is repeatedly inserted into the probe cleaning sheet of the present invention and then pulled up, thereby removing the foreign matter. When the tip of the probe penetrates the inside of the cleaning layer constituting the probe cleaning sheet of the present invention, it comes into contact with the abrasive particles and can remove impurities firmly attached to the probe.

[0044] The elastic material (foam) does not lose its elasticity even at high temperatures exceeding 200 degrees, and when the probe is pulled out, the shape of the elastic material is restored, capturing the scraped-off impurities inside the cleaning layer, thereby cleaning the probe.

[0045] [Example] The probe cleaning sheet according to the present invention will now be described more specifically with reference to examples.

[0046] A 500 μm thick polyimide resin foam was prepared, and a heat-resistant double-sided tape using a silicone adhesive was attached to one side of the foam.

[0047] Aluminum oxide (#4000: particle diameter 3 μm) was dispersed in a toluene solution of epoxy resin (epoxy resin concentration 70%) to a weight concentration of 50%, which was then applied to the surface of the foam opposite the double-sided tape and dried to form a polishing layer with a thickness of 10 μm.

[0048] This was cut into cleaning sheets measuring 100 mm x 100 mm.

[0049] [Comparative Example] Polyester urethane was used as the foam, and an abrasive layer was formed in the same manner as in the example, to prepare a cleaning sheet.

[0050] [Probe cleaning sheet performance evaluation] <Test Results> Using the above sheet, the cleaning ability and surface shape were evaluated in environments of 20°C, 120°C, and 200°C.

[0051] The needle surface was evaluated to see if it had been polished or not. [Table 1] ○: Good polishing ×: Polyurethane foam is softened and polishing is insufficient The surface was evaluated for removal of foreign matter. [Table 2] ○: Good cleaning ▲: Polyurethane foam is softened and cleaning is insufficient As shown in the above evaluation results, the cleaning sheet of the present invention had sufficient polishing effect (polishing the needle surface) and cleaning effect, and achieved the expected effect, even at a high temperature of 200° C. Conventionally known foams were inferior at 200° C., and the polishing effect and cleaning effect were insufficient. [Explanation of symbols]

[0052] 10 Probe cleaning sheets 20 Cleaning Layer 21 Elastic material (foam) 22 Polishing layer (abrasive particles) 25 Base sheet 26 Release sheet 27 Protective Sheet 28 Adhesive layer

Claims

1. A probe cleaning sheet having a cleaning layer for removing foreign matter adhering to the tip of a probe, A foamed resin layer of polyimide resin having resistance to temperatures exceeding 200 degrees; and an abrasive layer formed on the foamed resin layer, the abrasive layer being made of abrasive particles and a binder resin having resistance to temperatures exceeding 200 degrees. Probe cleaning sheet.

2. 2. The probe cleaning sheet according to claim 1, wherein the polyimide resin is replaced with a polyether ketone resin, a thermoplastic polyimide resin, a polyether sulfone resin, a polysulfone resin, a liquid crystal polymer resin, a polytetrafluoroethylene resin, or a fluorinated ethylene-perfluoroalkyl vinyl ether copolymer resin.

3. 2. The probe cleaning sheet of claim 1, wherein said abrasive particles are in the range of 0.01 μm to 13 μm.

4. 3. The probe cleaning sheet according to claim 2, wherein the abrasive particles are one or more of diamond, white alumina, silicon carbide, boron carbide, cerium oxide, zirconium oxide, chromium oxide, iron oxide, titanium oxide, silicon dioxide, manganese dioxide, manganese trioxide, zirconium silicate, barium carbonate, glass, boron nitride, and titanium nitride.

5. 2. The probe cleaning sheet of claim 1, wherein the binder resin is selected from the group consisting of an epoxy resin, a polyimide resin, and a silicone resin.

6. The probe cleaning sheet according to claim 1 , wherein an adhesive layer is provided on the foamed resin layer opposite the abrasive layer.

7. 7. The probe cleaning sheet of claim 6, wherein the adhesive layer is a heat-resistant double-sided tape attached with a silicone adhesive.

8. 2. The probe cleaning sheet of claim 1, wherein the abrasive layer is 10 μm.

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