Cleaning putty and method for cleaning semiconductor mounted components using the same

Abstract

This is a cleaning putty for cleaning semiconductor mounted components, and is mainly composed of a millable silicone rubber composition, has a plasticity of 20 or more and less than 80 according to JIS K 6300-3:2019 and ISO 2007:1991, and has an adhesive strength to aluminum of 0.3 N or more and 4 N or less. A cleaning method using this putty includes pressing the cleaning putty onto a printed circuit board to which a silicone-based heat dissipation material has been applied or attached, and peeling it off to clean the semiconductor mounted components. This provides a cleaning putty that does not adhere to the board or leads but selectively adheres to the silicone material to prevent damage to the components, and also provides a putty that has putty properties that allow it to penetrate into fine gaps, and a cleaning method for semiconductor mounted components using this putty.

Description

[Technical field]

[0001] The present invention relates to a cleaning putty and a method for cleaning semiconductor mounted components using the same. [Background technology]

[0002] Fine dust particles are often generated during the manufacturing process of printed circuit boards equipped with semiconductor elements such as CPUs (central processing units) and GPUs (graphics processing units). In addition, fine dust particles may be generated when thermally conductive grease or thermally conductive putty, which are heat dissipation materials for electronic components, are mounted on the electronic components. If this fine dust is not removed, the product will be rejected, resulting in a problem of reduced product yield. In addition, these heat dissipation materials must be removed when repairing or reapplying them, and if they are not removed sufficiently, problems such as reduced heat dissipation and contamination due to falling off can occur. Patent Document 1 proposes a silicone-based pressure-sensitive adhesive having a specific gel fraction and a specific degree of swelling in toluene. Patent Document 2 proposes a silicone-based pressure-sensitive adhesive having voids or cracks. Patent Document 3 proposes an addition reaction curing type silicone-based pressure-sensitive adhesive. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6626125 [Patent Document 2] JP 2004-123760 A [Patent Document 3] JP 2004-091703 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional adhesives adhere to the board and the leads attached to it, which can damage the components. Also, wiping with a cloth is not enough to clean the tiny gaps between the leads, so a needle is required to scrape them out, which takes a lot of time.

[0005] In order to solve the above-mentioned problems, the present invention provides a cleaning putty that does not stick to substrates or leads but selectively sticks to silicone materials to prevent damage to components and has putty properties that enable it to get into minute gaps, and a method for cleaning semiconductor mounted components using the same. [Means for solving the problem]

[0006] One embodiment of the present invention relates to a cleaning putty for cleaning semiconductor mounted components, the cleaning putty comprising a millable type silicone rubber composition as a main component, having a plasticity of 20 or more and less than 80 according to JIS K 6300-3:2019 and ISO 2007:1991, and an adhesive strength to aluminum of 0.3 N or more and 4 N or less.

[0007] Further, one embodiment of the present invention relates to a method for cleaning semiconductor-mounted components using the cleaning putty, which comprises pressing the cleaning putty against a printed circuit board to which a silicone-based heat dissipation material has been applied or attached, and then peeling it off to clean the semiconductor-mounted components. Effect of the Invention

[0008] The present invention provides a cleaning putty that uses a millable type silicone rubber composition as its main component, has a plasticity of 20 or more but less than 80 according to JIS K 6300-3:2019 and ISO 2007:1991, and has an adhesive strength to aluminum of 0.3 N or more but less than 4 N. This putty does not adhere to substrates or leads, but instead selectively adheres to silicone materials, thereby preventing damage to components, and also gives the putty properties that enable it to penetrate into tiny gaps, thereby significantly reducing the time and labor required for cleaning. It is also possible to provide a cleaning putty and a method for cleaning semiconductor mounted components using the same. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of a semiconductor mounting component according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic perspective view of a cleaning putty according to one embodiment of the present invention. [Diagram 3] FIG. 3 is a schematic perspective view of a cleaning putty according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention is a cleaning putty for cleaning semiconductor mounted components. The semiconductor mounted components include printed circuit boards equipped with semiconductor elements such as CPU (central processing unit) and GPU (graphics processing unit). The cleaning putty of the present invention is mainly composed of millable silicone rubber. Millable silicone rubber is a solid type silicone rubber, for example, a linear polymer with a degree of polymerization of 3000 to 10000 as a main component, and is a type of silicone rubber that is heat-cured using a vulcanizing agent and is in a clay state, which is blended with various additives such as silica-based reinforcing fillers, lubricants, and colorants. This millable silicone rubber is used to adjust the plasticity, adhesion, etc., to have excellent workability. In the above, the main component preferably contains 40% by mass or more of the millable silicone rubber relative to 100% by mass of the cleaning putty. The upper limit is 100% by mass. Within the above range, organopolysiloxane other than the millable silicone rubber may be included. The millable silicone rubber may also be uncrosslinked millable silicone rubber.

[0011] The cleaning putty of the present invention has a plasticity according to JIS K 6300-3:2019, ISO 2007:1991 of 20 or more and less than 80, preferably 20 or more and 75 or less, more preferably 20 or more and 70 or less. When the plasticity is in the above range, it is soft, has good conformability, and easily penetrates into fine gaps. When the plasticity is less than 20, it is too soft and easily torn off and easily remains between the reeds, and when the plasticity is 80 or more, it becomes hard and difficult to penetrate between the reeds, which is not preferable.

[0012] The cleaning putty of the present invention has an adhesive strength (tackiness) to aluminum of 0.3 N or more and 4 N or less, preferably 0.4 N or more and 3.8 N or less, and more preferably 0.5 N or more and 3.6 N or less. When the adhesive strength (tackiness) is within the above range, the putty does not adhere to the board or the lead, but adheres selectively to the silicone material, thereby preventing damage to the components. Also, the putty is less likely to damage the lead, etc.

[0013] When the cleaning putty is pressed against an aluminum block and then peeled off, it is preferable that no trace of interfacial destruction is left on the aluminum block side. Also, when the cleaning putty is pressed against a printed circuit board or silicone rubber and then peeled off, it is preferable that no trace of interfacial destruction is left on the printed circuit board side but on the silicone rubber side. This allows for efficient cleaning.

[0014] The cleaning putty preferably further contains an organopolysiloxane containing a boric acid compound, which makes it possible to provide a putty that does not further adhere to the substrate or leads but instead selectively adheres to the silicone material, thereby preventing damage to components and allowing the putty to penetrate into minute gaps.

[0015] When a heat dissipating material of a liquid thermally conductive silicone composition is applied to a printed circuit board so as to be 10 mm long, 20 mm wide and 0.3 mm thick, the mass is measured, and the cleaning putty is pressed against it and peeled off, it is preferable that the removal rate for the first time is 60 mass% and the removal rate for the second time is 85 mass% or more. This makes it possible to produce a putty that does not adhere to the board or leads but selectively adheres to the silicone material, preventing damage to components and allowing it to penetrate into minute gaps.

[0016] The cleaning putty of the present invention is preferably formed into a tape, sheet, rod or block shape, which allows it to clean various types of semiconductor mounted components.

[0017] The method for cleaning semiconductor mounted parts of the present invention involves pressing the cleaning putty onto a printed circuit board to which a silicone-based heat dissipation material has been applied or attached, and then peeling it off to clean the semiconductor mounted parts. This has the following advantages. (1) Improved workability, such as less sticking to hands, prevention of damage to components on the circuit board, and ability to be used over a large area, makes handling easier, and allows material that has gotten into narrow areas to be removed quickly and easily. (2) It has good compatibility with silicone, so liquid TIM can be adsorbed simply by pressing it against the material. (3) Because it is in the form of a soft putty, it can easily clean gaps less than 1 mm in size, such as gaps between reeds. (4) Since it can be pressed against a wide area, it can clean electronic components that are wide-ranging and have many bumps in them, all at once. (5) It does not adhere to the substrate material, but can remove only the silicone material.

[0018] The following description will be given with reference to the drawings. Figure 1 is a schematic cross-sectional view of a semiconductor mounted component 1 in one embodiment of the present invention. In this semiconductor mounted component 1, an IC chip 3 is mounted on a printed circuit board 2, and the printed circuit board 2 and IC chip 3 are electrically connected by leads 4 and gold wires 5, and the IC chip 3 is sealed with sealing resin 6. There are gaps 7a and 7b between the printed circuit board 2, the leads 4, and the sealing resin 6, and as an example, these will be cleaned.

[0019] Fig. 2 is a schematic perspective view of a cleaning putty 8 according to one embodiment of the present invention. This cleaning putty 8 is generally tape-shaped, with a tip portion having a thickness of 2 mm. Fig. 3 is a schematic perspective view of a cleaning putty 9 according to another embodiment of the present invention. This cleaning putty 9 has three grooves 10a, 10b, and 10c formed in the tip portion to increase the contact area with dust. The cleaning putty of the present invention is soft, and can be molded into any shape, such as a general tape, sheet, rod, or block shape. EXAMPLES

[0020] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0021] Various parameters were measured by the following methods. <Hardness (plasticity)> Hardness (plasticity) is measured in accordance with JIS K 6300-3, ISO 2007:1991 using a Wallace Rapid Plastometer. The sample is compressed between two metal plates at a constant load (300N) for a constant time (15 seconds) to a constant thickness (1mm) at a measurement temperature of 23°C, and then further compressed at a constant load (100N) for a constant time (15 seconds). The smaller this value, the more flexible the sample is. <Aluminum plate adhesive strength (tack strength)> Measurements were made using a tackiness checker HTC-1 (manufactured by Toyo Seiki Co., Ltd.). The contact was pressed against the object with the following pressure and time, and the stress when peeled off was detected by a load cell method. In the following examples, the pressure of the tackiness checker (manufactured by Toyo Seiki Co., Ltd.) was 10 N, the time was 6 seconds, and the contact was an aluminum F ring. <Interface failure between printed circuit board and silicone rubber> The printed circuit board material used was a general printed circuit board with solder resist processing, and the silicone rubber used was a silicone rubber sheet with a thickness of 1 mm. Measurement method (1) Press the sample against each material. (2) Peel off the sample and judge according to the following evaluation criteria. None: No sample remains on each material. Yes (small): A part of the sample remains. Yes (large): Most of the sample adheres and remains. <SPG-30B Cleaning Test> (SPG-30B is the product name of a thermally conductive silicone manufactured by Fuji Polymer Industry Co., Ltd.) Measurement method (1) Apply SPG-30B to a general substrate processed with solder resist so that it has a length of 10 mm, a width of 20 mm, and a thickness of 0.3 mm, and measure the weight. (2) Press the sample against the SPG so as to cover it. (3) Peel off the sample as it is and measure the remaining weight of the SPG. (First time) (4) Press the new surface of the sample again, peel it off, and measure the remaining weight of the SPG. (Second time) (5) Calculate the change rate from the initial weight and use it as the removal rate.

[0022] (Example 1) · 100 g of an uncrosslinked milable silicone rubber composition containing a diorganopolysiloxane and a boric acid compound, trade name "KE-1614H-U" manufactured by Shin-Etsu Chemical Co., Ltd. · 8 g of a polyorganosiloxane-based polymer, trade name "CF3110" manufactured by Toray Dow Corning Silicone Co., Ltd. Mix the above uniformly to obtain a cleaning paste.

[0023] (Example 2) · 100 g of an uncrosslinked milable silicone rubber composition containing a diorganopolysiloxane and a boric acid compound, trade name "KE-1614H-U" manufactured by Shin-Etsu Chemical Co., Ltd. · 20 g of a polyorganosiloxane-based polymer, trade name "CF3110" manufactured by Toray Dow Corning Silicone Co., Ltd. Mix the above uniformly to obtain a cleaning paste.

[0024] (Example 3) 100 g of uncrosslinked millable silicone rubber composition containing diorganopolysiloxane and boric acid compound, product name "KE-1614H-U" manufactured by Shin-Etsu Chemical Co., Ltd. Toray Dow Corning Silicone Co., Ltd., product name "CF3110": Polyorganosiloxane base polymer 37g The above ingredients were mixed uniformly to prepare a cleaning putty.

[0025] Example 4 - Toray Dow Corning Silicone Co., Ltd., product name "DAWSIL CF 9306": 100g of millable silicone rubber composition containing organopolysiloxane, silica, cristobalite, quartz, and diatomaceous earth Shin-Etsu Chemical Co., Ltd., product name "X-93-1169": 5g of organopolysiloxane additive containing boric acid compound Toray Dow Corning Silicone Co., Ltd., product name "CF3110": Polyorganosiloxane base polymer 20g The above ingredients were mixed uniformly to prepare a cleaning putty.

[0026] Example 5 100 g of a millable type silicone rubber composition, trade name "XIAMETER SE 1185 U" manufactured by Toray Dow Corning Silicone Co., Ltd., was used as a cleaning putty.

[0027] Example 6 - Toray Dow Corning Silicone Co., Ltd., product name "XIAMETER SE 1185 U": millable type silicone rubber composition 100g Shin-Etsu Chemical Co., Ltd., product name "X-93-1169": 5g of organopolysiloxane additive containing boric acid compound The above ingredients were mixed uniformly to prepare a cleaning putty.

[0028] Comparative Example 1 100 g of an uncrosslinked millable type silicone rubber composition containing diorganopolysiloxane and a boric acid compound, trade name "KE-1614H-U" manufactured by Shin-Etsu Chemical Co., Ltd., was used as a cleaning putty.

[0029] Comparative Example 2 100 g of uncrosslinked millable silicone rubber composition containing diorganopolysiloxane and boric acid compound, product name "KE-1614H-U" manufactured by Shin-Etsu Chemical Co., Ltd. Toray Dow Corning Silicone Co., Ltd., product name "CF3110": Polyorganosiloxane base polymer 74g The above ingredients were mixed uniformly to prepare a cleaning putty.

[0030] Comparative Example 3 - Toray Dow Corning Silicone Co., Ltd., product name "DAWSIL CF 9306": 100g of millable silicone rubber composition containing organopolysiloxane, silica, cristobalite, quartz, and diatomaceous earth Toray Dow Corning Silicone Co., Ltd., product name "CF3110": Polyorganosiloxane base polymer 20g The above ingredients were mixed uniformly to prepare a cleaning putty.

[0031] Comparative Example 4 A cleaning putty was made using a silicone adhesive whose main component was "DOWSIL SH 4280" (peroxide curing adhesive) manufactured by Toray Dow Corning Silicone Co., Ltd.

[0032] Comparative Example 5 Fuji Polymer Industries, product name "SARCON NR-c": A gel sheet using acrylic resin was kneaded into a putty-like material and used to make a cleaning putty.

[0033] The above conditions and results are shown in Tables 1 and 2.

[0034] [Table 1]

[0035] [Table 2]

[0036] The following is clear from Tables 1 and 2: (1) Examples 1 to 3 and Comparative Examples 1 and 2 were compared in terms of hardness (plasticity) range. All of Examples 1 to 3 were favorable, but Comparative Example 1 was too hard and did not penetrate between the leads, and Comparative Example 2 was too soft and was prone to tearing and remaining between the leads. (2) In Examples 4 and 6, the addition of the boric acid compound improved the performance in the SPG30B cleaning test compared to Comparative Example 3 and Example 5, respectively. (3) Comparative Example 4 is a silicone-based adhesive containing a peroxide-curing adhesive as a main component, but was not preferable because it caused a high degree of interfacial failure from the substrate and silicone rubber. (4) Comparative Example 5 was a putty-like gel sheet made of acrylic resin, but the adhesive strength to the aluminum was too high, it was easily torn off, and its performance in the SPG30B cleaning test was poor. Furthermore, the cleaning putties of Examples 1 to 6 of the present invention were also confirmed to have the following effects. (1) The cleaning putties of Examples 1 to 6 can be used to clean flat surfaces by simply pressing the putty against the surface and peeling it off, and are therefore easy to handle and have good work efficiency. (2) The gaps in the lead parts are about 0.3 to 0.5 mm. With conventional methods (e.g., commercially available tissue paper, Kimberly-Clark's product name "Kimwipe") and the cleaning putties of Comparative Examples 1 to 5, it was difficult to remove dust from the areas embedded in the lead parts, etc., and a needle was used to remove it. However, with the cleaning putties of Examples 1 to 6, it is possible to simply press the putties against even narrow areas and pull them off, which makes them easy to handle and efficient to work with. (3) Repairs are required due to application errors or after being turned in an environment of around 70°C. Similarly, these can be repaired by simply pressing cleaning putty against the surface and peeling it off, which is easy to handle and efficient to work with. [Industrial Applicability]

[0037] The cleaning putty of the present invention is suitable for cleaning semiconductor mounted components. [Explanation of symbols]

[0038] 1. Semiconductor mounting parts 2 Printed circuit board 2 3. IC chip 4 Lead Wire 5 Gold Wire 6 Sealing resin 7a,7b Gap 8,9 Cleaning putty 10a,10b,10c groove

Claims

1. A cleaning putty for cleaning semiconductor mounting components, The main component is a Mirable-type silicone rubber composition, and the plasticity is 20 or more and less than 80 according to JIS K 6300-3:2019 and ISO 2007:1991. A cleaning putty characterized by having an adhesive strength to aluminum of 0.3 N to 4 N.

2. The cleaning putty described in claim 1 is a cleaning putty that, when pressed onto an aluminum block and then peeled off, leaves no interface fracture marks on the aluminum block side.

3. The cleaning putty described in claim 1 is pressed onto a printed circuit board or silicone rubber and then peeled off, leaving no interface fracture marks on the printed circuit board side but leaving them on the silicone rubber side.

4. The cleaning putty according to claim 1, wherein the amount of the Mirable-type silicone rubber is 40% by mass or more and 100% by mass or less relative to 100% by mass of the cleaning putty.

5. The cleaning putty according to claim 1, further comprising an organopolysiloxane containing a boric acid compound.

6. The cleaning putty according to claim 1, further comprising an organopolysiloxane other than the millable-type silicone rubber.

7. The cleaning putty according to claim 1, wherein the millable-type silicone rubber composition comprises uncrosslinked millable-type silicone rubber.

8. The cleaning putty according to claim 1, wherein when a heat dissipation material of a liquid thermal conductive silicone composition is applied to a printed circuit board to a length of 10 mm, width of 20 mm, and thickness of 0.3 mm, the mass is measured, and the cleaning putty is pressed against it and peeled off, the removal rate in the first step is 60% by mass and the removal rate in the second step is 85% by mass or more.

9. The cleaning putty according to claim 1, wherein the cleaning putty is molded into the shape of a tape, sheet, rod, or block.

10. A method for cleaning semiconductor mounting components using the cleaning putty described in any one of claims 1 to 9, A method for cleaning semiconductor mounted components, characterized by pressing the cleaning putty onto a printed circuit board coated or attached with a silicone-based heat dissipation material, peeling it off, and cleaning the semiconductor mounted components.

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