Processing method

Abstract

To provide a processing method capable of suppressing wraparound of a resin.SOLUTION: Disclosed is a processing method for a tabular object having a front face and a rear face which is a back face with respect to the front face. The processing method includes: a protection step 101 of forming a protective layer which protects the front face of the tabular object; a holding step 102 of holding a front face side of the tabular object via the protective layer by means of a holding unit comprising a holding surface which holds the tabular object after the protection step 101 is implemented; a resin supply step 103 of supplying a resin for fixing the tabular object onto a sheet; and a fixing step 104 of opposing the rear face of the tabular object which is held by the holding unit to the sheet to which the resin is supplied, pressing and spreading the resin with the tabular object by moving the tabular object in relative to the sheet, and fixing the tabular object to the sheet via the resin.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for processing a plate-like object. [Background technology]

[0002] For example, semiconductor wafers are formed by slicing an ingot with a wire saw or the like to produce as-sliced ​​wafers, and then grinding and polishing both surfaces of the resulting wafers.

[0003] In order to remove waviness and warpage that occurs when slicing from an ingot, a resin is applied to one side of the as-sliced ​​wafer, hardened, and then the wafer is ground. An apparatus for applying the resin has been proposed (see, for example, Patent Document 1).

[0004] In the device shown in Patent Document 1, a sheet is placed on a stage to prevent the resin from adhering to the stage, and one side of a wafer, the other side of which is held by a holding unit, is pressed against resin supplied onto the sheet, spreading the resin over one side of the wafer and fixing the wafer to the sheet via the resin. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-33005 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the device disclosed in Patent Document 1, when the wafer is pressed against the resin, there is a risk that the resin may get onto the other side of the wafer held by the holding unit, which may cause processing defects during subsequent processing.

[0007] Specifically, if the second surface is subsequently ground, clogging occurs as the grinding wheel grinds away the resin that has gotten in. Also, if the subsequent processing is performed using a cutting blade, the wafer may become locally thick, resulting in poor cutting or insufficient cutting blade exposure, which could cause the flange or blade base to come into contact with the wafer.

[0008] Furthermore, if a protective layer is formed using tape instead of resin, it is difficult to peel off the wafer without damaging it, especially in the case of a thin wafer. Thus, there is a strong demand for improvements in the wraparound of the resin.

[0009] An object of the present invention is to provide a processing method that can suppress the wraparound of resin. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems and achieve the object, the processing method of the present invention is a processing method for a plate-like object having a first surface and a second surface behind the first surface, and is characterized by comprising: a protection step of forming a protective layer to protect the first surface of the plate-like object; a holding step of holding the first surface side of the plate-like object via the protective layer using a holding unit having a holding surface that holds the plate-like object after performing the protection step; a resin supply step of supplying resin to fix the plate-like object onto a sheet; and a fixing step of facing the second surface of the plate-like object held by the holding unit to the sheet onto which the resin has been supplied, and moving the plate-like object relative to the sheet to spread the resin with the plate-like object, and fixing the plate-like object to the sheet via the resin.

[0011] The processing method may include a removal step of removing the protective layer from the first surface of the plate-like object fixed to the sheet after the fixing step is performed, a sheet holding step of holding the sheet with a holding unit having a holding surface that holds the sheet and exposing the plate-like object after the removing step is performed, and a processing step of processing the exposed plate-like object after the sheet holding step is performed.

[0012] In the processing method, the protection step may involve covering the first surface of the plate-like object with a resin that hardens when subjected to an external stimulus and that can be peeled off by exposing it to water after hardening, and then applying the external stimulus to the resin to form the protective layer.

[0013] In the above processing method, the removing step may include removing the protective layer from the first surface of the plate-like object by supplying water to the protective layer. [Effects of the Invention]

[0014] The present invention has an effect of suppressing the resin from flowing around. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view showing an example of a plate-like object to be processed by the processing method according to the first embodiment. [Figure 2] FIG. 2 is a flowchart showing the flow of the processing method according to the first embodiment. [Figure 3] FIG. 3 is a side view, partly in section, schematically illustrating the protection step of the processing method shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view schematically showing the plate-like object after the protection step of the processing method shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view schematically showing the holding step of the processing method shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view schematically showing a resin supplying step of the processing method shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view schematically showing a state in which the holding unit is brought close to the support table in the fixing step of the processing method shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view schematically showing a state in which ultraviolet light is irradiated onto the liquid resin in the fixing step of the processing method shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a removing step of the processing method shown in FIG. [Figure 10] FIG. 10 is a side view, partly in section, schematically showing the sheet holding step of the processing method shown in FIG. [Figure 11] FIG. 11 is a side view, partly in section, schematically showing the processing steps of the processing method shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0017] [Embodiment 1] A processing method according to a first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view showing an example of a plate-like object to be processed by the processing method according to the first embodiment. Fig. 2 is a flowchart showing the flow of the processing method according to the first embodiment.

[0018] (plate-shaped object) The processing method according to the first embodiment is a method for processing a plate-like object 1 shown in Fig. 1. In the first embodiment, the plate-like object 1 is a wafer such as a disk-shaped semiconductor wafer or optical device wafer, which uses a substrate 2 made of silicon, sapphire, gallium, or the like, and has a front surface 4 which is a first surface, and a back surface 7 which is a second surface behind the front surface 4. As shown in Fig. 1, the plate-like object 1 has a plurality of planned division lines 5 set on the front surface 4 which intersect with each other, and devices 6 formed in areas defined by the planned division lines 5.

[0019] The device 6 is, for example, an integrated circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), or a memory (semiconductor storage device).

[0020] In the present invention, the plate-like object 1 may be something other than a disk-shaped wafer, and the device 6 may not be formed on the surface 4.

[0021] (Processing method) The processing method according to the first embodiment is also a method for dividing the plate-like object 1 into individual devices 6 along the planned division lines 5. As shown in FIG. 2 , the processing method according to the first embodiment includes a protection step 101, a holding step 102, a resin supply step 103, a fixing step 104, a removal step 105, a sheet holding step 106, and a processing step 107.

[0022] (protection step) Fig. 3 is a side view, partially in cross section, schematically showing the protection step of the processing method shown in Fig. 2. Fig. 4 is a cross-sectional view schematically showing the plate-like object after the protection step of the processing method shown in Fig. 2. This is a step of forming a protective layer 10 (shown in Fig. 4) that protects the surface 4 of the plate-like object 1.

[0023] In the first embodiment, in the protection step 101, a protection device 20 places the back surface 7 of the plate-like object 1 on the flat upper surface of a support table (not shown), and supplies protective resin 11 from a supply nozzle 21 facing the front surface 4 of the plate-like object 1, as shown in FIG. 3. In the first embodiment, the protective resin 11 is liquid and contains a water-based urethane acrylate (also referred to as a urethane acrylate aqueous solution in the present invention), a hydrophilic acrylate, and a photopolymerization initiator as a polymerization initiator. In the first embodiment, the protective resin 11 may contain a hydrophilic urethane acrylate and an acrylate aqueous solution, or may contain a water-based urethane acrylate and an acrylate aqueous solution.

[0024] Thus, in the present invention, the protective resin 11 may be a composition of at least one of a hydrophilic urethane acrylate and a hydrophilic acrylate in an aqueous solution, and may contain a photopolymerization initiator as a polymerization initiator. In addition, in the first embodiment, the protective resin 11 contains a photopolymerization initiator as a polymerization initiator that initiates polymerization when irradiated with ultraviolet light and hardens the protective resin 11, but in the present invention, the protective resin 11 may contain a polymerization initiator other than a photopolymerization initiator that hardens when heated, for example.

[0025] The hydrophilic urethane acrylate is a urethane acrylate having a so-called hydrophilic moiety. Examples of the hydrophilic urethane acrylate include KRM2000, EBECRYL 4587 (manufactured by Daicel-Allnex Co., Ltd.), UAW-1000W20 (manufactured by Kyoeisha Chemical Co., Ltd.), UV-W300, UT-7119 (manufactured by Mitsubishi Chemical Corporation), 8WX-022A, 8WX-030 (manufactured by Taisei Fine Chemical Co., Ltd.), or UA-7100, UA-W2A (manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0026] The hydrophilic acrylate is an acrylate having a so-called hydrophilic group, and examples thereof include hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, vinylpyrrolidone, ethoxyethoxyethyl methacrylate, ethoxyethoxyethyl acrylate, ethoxyethyl methacrylate, ethoxyethyl acrylate, methoxyethyl methacrylate, methoxyethyl acrylate, 1,3-butylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol methacrylate, polyethylene glycol 200 dimethacrylate, polyethylene glycol The copolymer may be selected from the group consisting of acrylic acid, poly(ethylene glycol) methyl ether methacrylate, polyethylene glycol methyl ether acrylate, glycidyl methacrylate, glycidyl acrylate, acrylic acid, methacrylic acid, 2-(trifluoromethyl)acrylic acid, phenylacrylic acid, acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, bisphenol-A-glycerol tetraacrylate, bisphenol-A-glycerol diacrylate, bisphenol-A-ethyleneoxydiacrylate, pentaerythritol triacrylate, or derivatives or mixtures of the above substances.

[0027] As a photopolymerization initiator, for example, Omnirad 2959 (manufactured by IGM Resins BV) is used.

[0028] The protective resin 11 described above is a resin that hardens when irradiated with ultraviolet light, and when exposed to water after hardening, absorbs water and swells, making it easily peelable from the surface 4 of the plate-like object 1. The protective resin 11 described above swells quickly if the amount of hydrophilic acrylate is large, and the swelling rate slows down as the amount of hydrophilic urethane acrylate increases, but if the amount of hydrophilic acrylate increases too much, it will not harden completely.

[0029] The protective resin 11 contains at least one of the hydrophilic urethane acrylate and the hydrophilic acrylate in an aqueous solution state, and the composition consisting of the hydrophilic urethane acrylate and the hydrophilic acrylate contains a photopolymerization initiator, which is a polymerization initiator. This is because if the hydrophilic urethane acrylate or the hydrophilic acrylate is used alone, it will not harden (semi-harden) even when irradiated with ultraviolet light, which is light, but if the protective resin contains both the hydrophilic urethane acrylate and the hydrophilic acrylate, it will harden when irradiated with ultraviolet light, which is light.

[0030] Furthermore, the protective resin 11 contains a photopolymerization initiator as a polymerization initiator in a composition consisting of the hydrophilic urethane acrylate and the hydrophilic acrylate, with at least one of the hydrophilic urethane acrylate and the hydrophilic acrylate in an aqueous solution state, because the hydrophilic acrylate does not swell on its own, does not swell without the aqueous urethane acrylate, and does not swell after curing unless both the hydrophilic urethane acrylate and the hydrophilic acrylate are in an aqueous solution state. This is presumably because at least one of the hydrophilic urethane acrylate and the hydrophilic acrylate swells when in an aqueous solution state.

[0031] The protective resin 11 described above, for example, if it contains hydrophilic urethane acrylate in an amount of 1 mass percent or more and 14 mass percent or less, hydrophilic acrylate in an amount of 30 mass percent or more and 90 mass percent or less, water in an amount of 4 mass percent or more and 56 mass percent or less, and photopolymerization initiator in an amount of 0.5 mass percent or more and 3 mass percent or less, will harden when irradiated with ultraviolet light, and will swell when exposed to water after hardening.

[0032] Furthermore, if the protective resin 11 contains, for example, 1.98 mass percent or more and 3.96 mass percent or less of hydrophilic urethane acrylate, 79.21 mass percent or more and 89.11 mass percent or less of hydrophilic acrylate, 7.92 mass percent or more and 15.84 mass percent or less of water, and 0.99 mass percent or more and 1.00 mass percent or less of photopolymerization initiator, the swelling time when exposed to water after curing will be shorter than the aforementioned ratio.

[0033] In embodiment 1, the protective resin 11 is composed of, for example, a composition consisting of a 20% concentration of aqueous urethane acrylate and methoxypolyethylene glycol acrylate, a hydrophilic acrylate, containing a photopolymerization initiator, and the ratio of each component is adjusted to the aforementioned ratio.

[0034] Thus, in the first embodiment, the protective resin 11 is a liquid ultraviolet curable resin, but in the present invention, it may be a liquid thermosetting resin or the like.

[0035] In the first embodiment, in the protection step 101, after supplying liquid protective resin 11 to the surface 4 of the plate-like object 1, ultraviolet light is irradiated from an ultraviolet irradiation means onto the protective resin 11 on the surface 4 of the plate-like object 1, thereby hardening the protective resin 11 on the surface 4 of the plate-like object 1, and the protective resin 11 is formed into a protective layer 10 as shown in Fig. 4. In the first embodiment, in the protection step 101, it is preferable to interpose a release paper or the like that can be easily peeled off from the hardened protective layer 10 between the back surface 7 of the plate-like object 1 and the upper surface of the support base, so that the support base and the protective resin 11 do not come into contact with each other.

[0036] Thus, in embodiment 1, in the protection step 101, the surface 4 of the plate-like object 1 is coated with a protective resin 11, which is a resin that hardens when subjected to an external stimulus and can be peeled off by exposing it to water after hardening, and an external stimulus is applied to the protective resin 11 to form a protective layer 10.

[0037] (holding step) Fig. 5 is a cross-sectional view schematically showing the holding step of the processing method shown in Fig. 2. Holding step 102 is a step in which, after protection step 101 is performed, front surface 4 of plate-like object 1 is held via protective layer 10 by holding unit 31 having holding surface 32 for holding plate-like object 1.

[0038] In the first embodiment, in the holding step 102, as shown in Fig. 5, the protective layer 10 on the surface 4 of the plate-like object 1 is brought into close contact with a flat holding surface 32 made of a porous material such as porous ceramics, which is connected to a suction source 35 via a suction path 33 and an on-off valve 34 of a holding unit 31 of a resin fixing device 30. In the first embodiment, in the holding step 102, as shown in Fig. 5, the on-off valve 34 is opened to suck the holding surface 32 with the suction source 35, and the surface 4 side of the plate-like object 1 is held by suction on the holding surface 32 of the holding unit 31.

[0039] (Resin supply step) Fig. 6 is a cross-sectional view schematically showing the resin supplying step of the processing method shown in Fig. 2. The resin supplying step 103 is a step of supplying resin 12 onto sheet 13 to fix plate-like object 1.

[0040] In the first embodiment, in the resin supplying step 103, as shown in Fig. 6, the resin fixing device 30 places the sheet 13 on the upper surface 37 opposite the holding surface 32 of the holding unit 31 of the support stand 36 made of flat glass, and supplies the liquid resin 12 onto the sheet 13. In the first embodiment, the sheet 13 is made of a non-swelling resin such as PET (Polyethylene terephthalate) resin, and is formed in a disk shape with a diameter larger than that of the plate-like object 1.

[0041] Furthermore, the liquid resin 12 is liquid before an external stimulus is applied, and is configured from a resin that hardens when an external stimulus is applied. In the first embodiment, the liquid resin 12 hardens when irradiated with ultraviolet light 39 (shown in FIG. 8), which is an external stimulus, but in the present invention, the liquid resin 12 may also harden when heated, which is an external stimulus.

[0042] (fixed step) Fig. 7 is a cross-sectional view schematically showing a state in which the holding unit is brought close to the support table in the fixing step of the processing method shown in Fig. 2. Fig. 8 is a cross-sectional view schematically showing a state in which ultraviolet light is irradiated onto the liquid resin in the fixing step of the processing method shown in Fig. 2.

[0043] Fixing step 104 is a step in which back surface 7 of plate-like object 1 held by holding unit 31 is made to face sheet 13 to which liquid resin 12 has been supplied, and plate-like object 1 is moved relative to sheet 13 to spread liquid resin 12 with plate-like object 1, thereby fixing plate-like object 1 to sheet 13 via resin 12. In embodiment 1, in fixing step 104, resin fixing device 30 brings back surface 7 of plate-like object 1, which is suction-held on holding surface 32 of holding unit 31, opposite upper surface 37 of support table 36, and then, as shown by the arrow in FIG. 7 , brings holding unit 31 close to upper surface 37 of support table 36 in a direction perpendicular to holding surface 32 and upper surface 37.

[0044] In the first embodiment, in the fixing step 104, the resin fixing device 30 spreads the liquid resin 12 on the sheet 13 with the back surface 7 of the plate-like object 1 held by suction on the holding surface 32 of the holding unit 31. In the first embodiment, in the fixing step 104, as shown in Fig. 8 , ultraviolet rays 39 from an ultraviolet irradiation means 38 below the support table 36 are irradiated onto the liquid resin 12 through the support table 36, thereby hardening the liquid resin 12 applied to the back surface 7 of the plate-like object 1, and the back surface 7 of the plate-like object 1 is fixed to the sheet 13 via the hardened resin 12.

[0045] (Removal step) Fig. 9 is a cross-sectional view schematically showing the removing step of the processing method shown in Fig. 2. The removing step 105 is a step of removing the protective layer 10 from the surface 4 of the plate-like object 1 fixed to the sheet 13 after the fixing step 104 is performed.

[0046] In the first embodiment, in the removal step 105, a removal device 40 places the back surface 7 of the plate-like object 1 on the flat upper surface of a support table (not shown) with the cured resin 12 and sheet 13 between them, and supplies pressurized pure water 42 (corresponding to water) to the front surface 4 of the plate-like object 1 from a nozzle 41 facing the front surface 4 of the plate-like object 1, as shown in FIG. 9 . In the first embodiment, in the removal step 105, the removal device 40 swells the protective layer 10 and removes the swollen protective layer 10 from the front surface 4 of the plate-like object 1 by the water pressure of the pure water 42. Thus, in the first embodiment, in the removal step 105, the protective layer 10 is removed from the front surface 4 of the plate-like object 1 by supplying the pure water 42 to the protective layer 10.

[0047] (Seat holding step) Fig. 10 is a side view, partially in cross section, schematically showing the sheet holding step of the processing method shown in Fig. 2. The sheet holding step 106 is a step in which, after the removal step 105 is performed, the sheet 13 is held by a holding unit 51 having a holding surface 52 for holding the sheet 13, and the plate-like object 1 is exposed.

[0048] In the first embodiment, in the sheet holding step 106, the cutting device 50, which is a processing device, places the back surface 7 of the plate-like object 1 on the holding surface 52 of the holding unit 51 via the sheet 13 and the cured resin 12, as shown in Fig. 10. In the first embodiment, in the sheet holding step 106, the cutting device 50 suction-holds the back surface 7 of the plate-like object 1 on the holding surface 52 of the holding unit 51 via the sheet 13 and the cured resin 12.

[0049] (Processing step) Fig. 11 is a side view, partially in cross section, schematically showing the processing steps of the processing method shown in Fig. 2. Processing step 107 is a step of processing the exposed plate-like object 1 after sheet holding step 106 is performed.

[0050] In the first embodiment, in the processing step 107, the cutting device 50 captures an image of the plate-like object 1 with the imaging unit, and performs alignment of the plate-like object 1 with the cutting blade 53 shown in Fig. 11 based on the image captured by the imaging unit. In the first embodiment, in the processing step 107, the cutting device 50 relatively moves the holding unit 51 and the cutting blade 53, which rotates about its axis by the spindle of the cutting unit 54, along the planned division lines 5, as shown in Fig. 11, and cuts the cutting blade 53 into each planned division line 5 from the front surface 4 side of the plate-like object 1 until it reaches at least one of the sheet 13 and the hardened resin 12, thereby performing a cutting process (corresponding to processing) on ​​the plate-like object 1 and dividing the plate-like object 1 into individual devices 6.

[0051] In the present invention, in processing step 107, a processing device such as a laser processing device, a grinding device, a polishing device, or a tool cutting device may perform laser processing, grinding processing, polishing processing, or tool cutting processing on plate-like object 1. In these cases, it is desirable that these processing devices form protective layer 10 on one of front surface 4 and back surface 7 of plate-like object 1, and then fix sheet 13 to the other surface via hardened resin 12, remove protective layer 10, and then perform processing.

[0052] The processing method according to the first embodiment described above forms the protective layer 10 that protects the surface 4 of the plate-like object 1 in the protection step 101 before the fixing step 104 is performed, and therefore, even if the resin 12 creeps around to the surface 4 side when the sheet 13 is fixed to the back surface 7 of the plate-like object 1 via the resin 12 in the fixing step 104, it is possible to prevent the resin 12 from adhering to the surface 4 of the plate-like object 1. Furthermore, the processing method according to the first embodiment removes the protective layer 10 from the surface 4 of the plate-like object 1 in the removal step 105.

[0053] As a result, the processing method according to the first embodiment has the effect of suppressing the resin 12 from flowing around to the front surface 4 of the plate-like object 1.

[0054] Furthermore, in the processing method according to embodiment 1, the protective layer 10 is formed using a protective resin 11 that swells in water, so that the protective layer 10 can be easily peeled off from the plate-like object 1, and even when the plate-like object 1 is a wafer, the protective layer 10 can be peeled off without damaging the plate-like object 1.

[0055] The present invention is not limited to the above-described embodiment, and can be implemented in various modifications without departing from the gist of the present invention. [Explanation of symbols]

[0056] 1 Plate-shaped object 4 Surface (first side) 7 Back side (2nd side) 10 protective layer 12 Resin 13 sheets 31 Holding Unit 32 Holding surface 42 Pure water (water) 51 Holding Unit 52 Holding surface 101 Protective Steps 102 Retention Steps 103 Resin supply step 104 Fixed Steps 105 Removal Steps 106 Sheet holding step 107 Processing Steps

Claims

1. A method for processing a plate-like object having a first surface and a second surface behind the first surface, comprising: a protection step of forming a protection layer to protect the first surface of the plate-like object; a holding step of holding the first surface side of the plate-like object via the protective layer using a holding unit having a holding surface that holds the plate-like object after the protecting step is performed; a resin supplying step of supplying a resin onto the sheet to fix the plate-like object; a fixing step in which the second surface of the plate-like object held by the holding unit is made to face the sheet to which the resin has been supplied, and the plate-like object is moved relative to the sheet to spread the resin with the plate-like object, thereby fixing the plate-like object to the sheet via the resin.

2. a removing step of removing the protective layer from the first surface of the plate-like object fixed to the sheet after the fixing step is performed; a sheet holding step of holding the sheet with a holding unit having a holding surface for holding the sheet and exposing the plate-like object after the removing step is performed; 2. The processing method according to claim 1, further comprising a processing step of processing the exposed plate-like object after the sheet holding step is performed.

3. The processing method described in claim 1, wherein the protection step comprises covering the first surface of the plate-like object with a resin that hardens when subjected to an external stimulus and that can be peeled off by exposing it to water after hardening, and then applying the external stimulus to the resin to form the protective layer.

4. The processing method according to claim 2 , wherein the removing step removes the protective layer from the first surface of the plate-like object by supplying water to the protective layer.

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