Method for removing foreign objects

Abstract

To provide a foreign matter removal method for removing a foreign matter attached to a plate-like object such as a wafer, which can reduce the cost and suppress the possibility of occurrence of new problems.SOLUTION: A foreign matter removal method for removing a foreign matter 300 attached to a plate-like object 100 includes: a preparation step of preparing a resin member 200 having tack strength; a pressing step of pressing a resin member 200 having a tack force against a foreign matter removal target surface of the plate-like object 100; and a peeling step of peeling the resin member 200 having a tack force from the plate-like object 100 after carrying out the pressing step, in which the foreign matter 300 attached to the plate-like object 100 is removed by the tack force of the resin member 200.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for removing foreign matter. [Background technology]

[0002] Semiconductor devices are formed by thinning the back surface of a semiconductor wafer through grinding and polishing, and then dividing it along streets set on the wafer. While this processing is usually carried out in a cleanroom, foreign matter (particles) such as dust and debris may adhere to the wafer for various reasons. Attempting the aforementioned processing on a wafer contaminated with these foreign matter can lead to cracking or chipping. Therefore, it is desirable to remove such foreign matter before processing, and various methods such as cleaning and air blowing have been proposed. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2014-018760 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, removing foreign matter by washing requires the use of chemicals and pure water, which is costly and time-consuming, posing a challenge to productivity. Removal by air blowing presents a different problem: it cannot completely remove firmly attached foreign matter. Therefore, a method of removing foreign matter by attaching a tape with an adhesive layer to the wafer (see, for example, Patent Document 1) was proposed, but this presented a new problem: the adhesive layer remained on the wafer.

[0005] The present invention has been made in view of the above problems, and its purpose is to provide a method for removing foreign matter adhering to plate-shaped objects such as wafers, which reduces costs and suppresses the risk of new problems arising. [Means for solving the problem]

[0006] To solve the above-mentioned problems and achieve the objective, the present invention provides a method for removing foreign matter adhering to a plate-shaped object, comprising: a preparation step of preparing a resin member having tack force; a pressing step of pressing the resin member having tack force against the surface of the plate-shaped object from which foreign matter is to be removed; and a peeling step of peeling the resin member having tack force from the plate-shaped object after performing the pressing step, wherein the tack force of the resin member removes the foreign matter adhering to the plate-shaped object. The resin member having the tack force contains a metal-catching group. It is characterized by doing so.

[0007] The pressing step and the peeling step may be performed on the surface of the plate-like material to be processed, from which foreign matter is to be removed. Furthermore, the metal-catching groups contained in the resin member may have functional groups that can bond with the resin member. Also, the resin member may have reactive groups that react with the metal-catching groups contained in the resin member. You may have it.

[0008] The resin member having the tack force The storage modulus is 1 × 10⁻⁶ 6 Pa or higher, and 1 × 10 9 Below Pa That's fine. [Effects of the Invention]

[0009] This invention allows for the removal of foreign matter adhering to a plate-like object by pressing a resin member with tack force onto the plate-like object and peeling it off, thereby reducing costs and suppressing the risk of new problems arising. Furthermore, the storage modulus of the resin member is 1 × 10⁻⁶. 6 Pa or higher, and 1 × 10 9 Because the pressure is below Pa, it possesses tack force, allowing it to adequately adsorb foreign matter attached to a plate-like object when the resin component is brought into contact with the plate-like object. Furthermore, if the resin component possessing tack force contains metal-catching groups, these groups can adsorb metal contamination on the plate-like object at the molecular level. [Brief explanation of the drawing]

[0010] [Figure 1] FIG. 1 is a perspective view showing an example of a plate-shaped object to which the foreign matter removal method according to the embodiment is applied. [Figure 2] FIG. 2 is a flowchart showing the processing procedure of the foreign matter removal method according to the embodiment. [Figure 3] FIG. 3 is a perspective view for explaining an example of the pressing step in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view for explaining an example of the pressing step in FIG. 2. [Figure 5] FIG. 5 is a perspective view for explaining an example of the peeling step in FIG. 2. [Figure 6] FIG. 6 is a cross-sectional view for explaining an example of the peeling step in FIG. 2.

MODE FOR CARRYING OUT THE INVENTION

[0011] The mode (embodiment) for carrying out the present invention will be described in detail while referring to the drawings. The present invention is not limited by the content described in the following embodiments. Further, the constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Also, various omissions, substitutions, or changes in the configuration can be made without departing from the gist of the present invention.

[0012] 〔Embodiment〕 A method for removing foreign matter according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a perspective view showing an example of a plate-shaped object 100 that is the target of the foreign matter removal method according to the embodiment. In this embodiment, the plate-shaped object 100 that is the target of the foreign matter removal method according to the embodiment is, for example, a disc-shaped semiconductor wafer or optical device wafer made of silicon, sapphire, silicon carbide (SiC), gallium arsenide, etc. as a base material, as shown in Figure 1. The plate-shaped object 100 has devices 103 such as chip-sized semiconductor devices or optical devices formed in areas demarcated by a plurality of streets (planned division lines) 102 formed in a grid pattern on a flat surface 101. Furthermore, in the present invention, the plate-shaped object 100 is not limited to these wafers, and may also be a rectangular package substrate having a plurality of devices sealed with resin, a ceramic plate, or a glass plate, etc.

[0013] Figure 2 is a flowchart showing the processing procedure of the foreign matter removal method according to the embodiment. Figures 3 and 4 are a perspective view and a cross-sectional view illustrating an example of the pressing step 1002 in Figure 2, respectively. Figures 5 and 6 are a perspective view and a cross-sectional view illustrating an example of the peeling step 1003 in Figure 2, respectively. As shown in Figure 2, the foreign matter removal method according to the embodiment comprises a preparation step 1001, a pressing step 1002, and a peeling step 1003, and uses a resin member 200 (see Figure 3, etc.) that has tack force against a plate-shaped object 100 to remove foreign matter 300 (particles, see Figure 4) such as dust and debris attached to the plate-shaped object 100 by the tack force of the resin member 200. The foreign matter 300 is, for example, processing scraps generated by processing the plate-shaped object 100.

[0014] Preparation step 1001 is the step of preparing a resin member 200 having tack force. Here, the resin member 200 having tack force means, in this specification, that the resin member 200 adheres more strongly to the foreign object 300 than the material used for the plate-like object 100, and that even if the surface of the resin member 200 to which the foreign object 300 is attached is tilted, the foreign object 300 does not separate from the surface of the resin member 200.

[0015] The resin member 200 having a tack force used in the foreign matter removal method according to the embodiment has a storage elastic modulus (dynamic storage elastic modulus) of 1×10 6 Pa or more and 1×10 9 Pa or less under the environment when used in the foreign matter removal method according to the embodiment.

[0016] The storage elastic modulus is measured by dynamic elastic modulus measurement (Dynamic Mechanical Analysis, DMA) together with the loss elastic modulus (dynamic loss elastic modulus) and the loss tangent. Specifically, the storage elastic modulus is measured by a method conforming to any of JIS K 7244-4 (non-resonant forced vibration method), JIS K 7244-5 (bending mode), and JIS K 7244-6 (shearing mode) of Japanese Industrial Standards. According to the Japanese Industrial Standards, when the storage elastic modulus is less than 0.01 GPa (1×10 7 GPa), it is preferably measured by a method conforming to JIS K 7244-6 (shearing mode), and when it is 0.01 GPa or more and 5 GPa or less (1×10 7 GPa or more and 5×10 9 GPa or less), it is preferably measured by a method conforming to JIS K 7244-4 (non-resonant forced vibration method), and when it is more than 5 GPa (5×10 9 GPa), it is preferably measured by a method conforming to JIS K 7244-5 (bending mode).

[0017] The storage elastic modulus generally varies depending on the temperature at the time of measurement and the frequency (speed) of the deformation applied at the time of measurement. More specifically, the resin member 200 having a tack force used in the foreign matter removal method according to the embodiment has a storage elastic modulus measured under the conditions that the temperature is the use environment temperature and the frequency of deformation is 0.01 Hz or more and 10 Hz or less satisfying 1×10 6 Pa or more and 1×10 9 Pa or less. Hereinafter, the conditions that the temperature is the use environment temperature (here, for example, 20°C) and the frequency of deformation is 0.01 Hz or more and 10 Hz or less are abbreviated as predetermined conditions.

[0018] The resin member 200 has a storage elastic modulus measured under predetermined conditions of 1×106 Pa or more 1×10 9 Since it is less than Pa, it has a tack force, meaning it adheres more strongly to the foreign matter 300 than the material used for the plate-shaped object 100, and even when the surface of the resin member 200 to which the foreign matter 300 is attached is tilted, the foreign matter 300 does not detach from the surface of the resin member 200. This allows the resin member 200 to sufficiently adsorb the foreign matter 300 attached to the plate-shaped object 100 when it is brought into contact with the plate-shaped object 100.

[0019] On the other hand, the storage modulus of the resin component, measured under predetermined conditions, is 1 × 10⁻⁶. 6 If the storage modulus is less than Pa, the resin component may become too sticky, and when the resin component is brought into contact with the plate-like object 100, there is a risk that residue derived from the resin component will remain on the plate-like object 100. Furthermore, the storage modulus of the resin component, as measured under predetermined conditions, is 1 × 10⁻⁶. 9 If the Pa value is higher, the resin component may be too hard, and when the resin component is brought into contact with the plate-shaped object 100, it may not be able to adequately adsorb the foreign matter 300 attached to the plate-shaped object 100.

[0020] In this embodiment, the resin member 200 is made of a thermoplastic resin. Specifically, the thermoplastic resins that make up the resin member 200 include acrylic resin, methacrylic resin, vinyl resin, polyacetal, natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, polyolefins such as polyethylene, polypropylene, poly(4-methyl-1-pentene), and poly(1-butene), polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon-6, nylon-66, and polymetaxylene adipamide, polyacrylate, polymethacrylate, polyvinyl chloride, polyetherimide, and polyacrylonitrile. Examples include one or more selected from polycarbonate, polystyrene, polysulfone, polyethersulfone, polyphenylene, etherpolybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, thermoplastic polyurethane resin, phenoxy resin, polyamideimide resin, fluororesin, ethylene-unsaturated carboxylic acid copolymer resin, ethylene-vinyl acetate copolymer resin, ionomer, ethylene-vinyl acetate-maleic anhydride ternary copolymer resin, ethylene-vinyl acetate copolymer saponified resin, and ethylene-vinyl alcohol copolymer resin.

[0021] Examples of unsaturated carboxylic acids that constitute the ethylene-unsaturated carboxylic acid copolymer resin used in the thermoplastic resin constituting the resin member 200 include acrylic acid, methacrylic acid, maleic acid, itaconic acid, monomethyl maleate, monoethyl maleate, maleic anhydride, and itaconic anhydride. Here, the ethylene-unsaturated carboxylic acid copolymer resin includes not only a binary copolymer of ethylene and an unsaturated carboxylic acid, but also a polypolymer in which other monomers are copolymerized. Examples of other monomers that may be copolymerized in the ethylene-unsaturated carboxylic acid copolymer resin include vinyl esters such as vinyl acetate and vinyl propionate, and unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, isobutyl methacrylate, dimethyl maleate, and diethyl maleate.

[0022] The resin member 200 is made of the thermoplastic resin described above, and the storage modulus measured under predetermined conditions is 1 × 10⁻⁶ 6 Pa or more 1×10 9 The storage modulus of the resin member 200, measured under predetermined conditions, is 1 × 10⁻⁶. 6 Pa or more 1×10 9 The thermoplastic resin used in the resin member 200, its molecular weight, and its combination are appropriately selected from the above-mentioned thermoplastic resins so as to be less than or equal to Pa, and the mixing ratio is appropriately determined.

[0023] Furthermore, the resin member 200 may also contain a metal-scavenging group. The metal-scavenging group used in combination with the resin member 200 is a material that can adsorb metal contamination on the plate-like object 100 at the molecular level. Examples include chelating agents, calixarenes, zeolites, activated carbon, mesoporous silica, and crown ethers.

[0024] In particular, some of the metal-scavenging groups, such as chelating agents, calixarenes, and crown ethers, have functional groups that can bond with the thermoplastic resin constituting the resin member 200. By bonding with the thermoplastic resin, the detachment of the metal-scavenging groups from the resin member 200 during peeling from the plate-like object 100 can be suppressed.

[0025] Furthermore, among the thermoplastic resins constituting the resin member 200, ethylene-unsaturated carboxylic acid copolymer resins, ethylene-vinyl acetate copolymer resins, ionomers, ethylene-vinyl acetate-maleic anhydride ternary copolymer resins, ethylene-vinyl acetate copolymer saponified resins, and ethylene-vinyl alcohol copolymer resins have reactive groups that react with the metal-catching groups mentioned above. Therefore, by using these thermoplastic resins in the resin member 200, the detachment of the metal-catching groups from the resin member 200 during peeling from the plate-like object 100 can be suppressed.

[0026] In preparation step 1001, the storage modulus measured under predetermined conditions is 1 × 10⁻⁶. 6 Pa or more 1×109 In order to achieve a pressure of Pa or less, the thermoplastic resin used for the resin member 200, its molecular weight, and its combination are appropriately selected from the above-mentioned thermoplastic resins, their mixing ratio is appropriately determined, and metal scavenging groups to be mixed are selected as needed. The resin member 200 is formed by appropriately mixing and molding these materials. In the preparation step 1001, as shown in Figure 3, the resin member 200 is formed into a shape that is easy to press onto the plate-like object 100 in the subsequent pressing step 1002, for example, in the form of a sheet. In this way, by performing the preparation step 1001, a resin member 200 with tack force is prepared in a shape (for example, a sheet) that is easy to press onto the plate-like object 100 in the subsequent pressing step 1002.

[0027] The pressing step 1002 is a step in which a resin member 200 having tack force is pressed against the surface of the plate-shaped object 100 from which foreign matter is to be removed. Specifically, in the pressing step 1002, as shown in Figure 3, the surface of the plate-shaped object 100 from which foreign matter is to be removed is brought into contact with one side of the resin member 200, and then the pressing roller 10 is rotated and moved from one end of the plate-shaped object 100 on the side of the surface from which foreign matter is to be removed to the other end via the resin member 200, thereby pressing the resin member 200 against the surface of the plate-shaped object 100 from which foreign matter is to be removed and making it adhere to it. By performing the pressing step 1002 in this way, as shown in Figure 4, the portion of the resin member 200 pressed against the surface of the plate-shaped object 100 from which foreign matter is to be removed can adsorb the foreign matter 300 attached to the surface of the plate-shaped object 100 due to the tack force of the resin member 200. In this embodiment, the surface of the plate-like object 100 from which foreign matter is to be removed is the front surface 101, but the present invention is not limited to this, and may also be the back surface 104.

[0028] The peeling step 1003 is a step in which the resin member 200, which has tack force, is peeled off the plate-shaped object 100 after the pressing step 1002 has been performed. In the peeling step 1003, as shown in Figures 5 and 6, the resin member 200, which has been pressed and adhered to the surface of the plate-shaped object 100 from which foreign matter is to be removed, is pulled, for example, from one end of the plate-shaped object 100 on the side of the surface from which foreign matter is to be removed to the other end, thereby peeling the resin member 200 off the surface of the plate-shaped object 100 from which foreign matter is to be removed. By performing the peeling step 1003 in this way, as shown in Figure 6, the tack force of the resin member 200 can remove the foreign matter 300 that was attached to the surface of the plate-shaped object 100 from which foreign matter was to be removed, which was adsorbed by the resin member 200 when the pressing step 1002 was performed.

[0029] The method for removing foreign matter according to the embodiment having the above configuration can remove foreign matter 300 adhering to the plate-shaped object 100 by pressing a resin member 200 having tack force against the plate-shaped object 100 and peeling it off. Therefore, the method for removing foreign matter according to the embodiment does not require the use of chemicals or pure water as in conventional forms, and furthermore, it does not require time for washing and drying, thus reducing the cost of removing foreign matter and improving productivity. In addition, the method for removing foreign matter according to the embodiment can suppress the risk of a different problem occurring, such as the inability to completely remove firmly adhering foreign matter, as in forms that use air blowing. Furthermore, since the resin member 200 having tack force used to remove foreign matter 300 in the method for removing foreign matter according to the embodiment does not have an adhesive layer, it can suppress the risk of a new problem occurring, such as the adhesive layer remaining on the plate-shaped object 100, as in conventional forms that remove foreign matter by attaching a tape with an adhesive layer to the plate-shaped object 100. As described above, the method for removing foreign matter according to the embodiment has the effect of reducing such costs and suppressing the risk of new problems occurring.

[0030] Furthermore, the method for removing foreign matter according to the embodiment assumes that the storage modulus of the resin member 200 under predetermined conditions is 1 × 10 6 Pa or higher, and 1 × 10 9Since it is less than Pa, it has a tack force, meaning it adheres more strongly to the foreign matter 300 than the material used for the plate-shaped object 100, and even when the surface of the resin member 200 to which the foreign matter 300 is attached is tilted, the foreign matter 300 does not detach from the surface of the resin member 200. This allows the resin member 200 to sufficiently adsorb the foreign matter 300 attached to the plate-shaped object 100 when it is brought into contact with the plate-shaped object 100.

[0031] Furthermore, in the method for removing foreign matter according to the embodiment, since the resin member 200 having tack force contains metal-catching groups, metal contamination on the plate-like object 100 can be adsorbed at the molecular level by the metal-catching groups.

[0032] It should be noted that the present invention is not limited to the embodiments described above. That is, it can be implemented with various modifications without departing from the core principles of the present invention. [Explanation of symbols]

[0033] 100 Plate-like objects 101 Surface 104 Back side 200 Resin components 300 Foreign object

Claims

1. A method for removing foreign matter adhering to a plate-like object, A preparation step to prepare a resin member having tack force, A pressing step in which a resin member having tack force is pressed against the surface of the plate-shaped object from which foreign matter is to be removed, The system includes a peeling step in which, after performing the pressing step, the resin member having the tack force is peeled off from the plate-like object, The tack force of the resin member removes foreign matter adhering to the plate-shaped object. A method for removing foreign matter, characterized in that the resin member having tackiness contains a metal-catching group.

2. The method for removing foreign matter according to Claim 1, characterized in that the pressing step and the peeling step are performed on the surface of the plate-shaped object to be removed before processing.

3. The method for removing foreign matter according to claim 1 or 2, characterized in that the metal-catching group contained in the resin member has a functional group that can bond with the resin member.

4. The method for removing foreign matter according to claim 1, 2, or 3, characterized in that the resin member has a reactive group that reacts with a metal-trapping group contained in the resin member.

5. The storage modulus of the resin member having the tack force is 1 × 10 ６ Pa or greater, and 1 × 10⁻⁶ ９ A method for removing foreign matter according to claim 1, 2, 3, or 4, characterized in that the pressure is Pa or less.

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