Protective film agent and method for processing a workpiece

Abstract

The present invention provides a protective film agent and a method for processing a workpiece, the protective film agent being capable of forming a protective film suitable for processing with a laser beam. The protective film agent is coated on a workpiece when the workpiece is processed, the protective film agent comprising: a water-soluble resin; a light absorber having a flavone structure, a flavonol structure, or an isoflavone structure; and a solvent that dissolves the resin and the light absorber.

Description

Technical Field

[0001] The present invention relates to a protective film agent for coating a workpiece, and a processing method for the workpiece using the protective film agent. Background Technology

[0002] In electronic devices such as mobile phones and personal computers, device chips containing electronic circuits and other components are essential components. Device chips are obtained, for example, by dividing the surface of a wafer made of semiconductors such as silicon (Si) into multiple regions using pre-defined processing lines called spacers, forming devices in each region, and then dividing the wafer along these pre-defined processing lines.

[0003] When dividing a wafer into smaller pieces such as device chips, a cutting device is used, for example, with a ring-shaped tool called a cutting tool mounted on the spindle. The cutting tool is rotated at high speed, and while a liquid such as pure water is supplied, it cuts into the wafer along a predetermined processing line, thereby enabling the wafer to be cut and divided into multiple smaller pieces (see, for example, Patent Document 1).

[0004] In recent years, a technique for dicing wafers using highly reactive plasma has also been proposed (see, for example, Patent Document 2). This technique can process the entire wafer in one pass using plasma, so even with the increase in wafer size or device miniaturization and the extension of the total distance of the pre-defined processing lines, the time required for wafer dicing will not increase. Furthermore, since no cutting tools or other tools used for machining the wafer are used, problems such as wafer defects caused by contact with such tools are avoided.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 3-198363

[0008] Patent Document 2: Japanese Patent Application Publication No. 2016-207737 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] Incidentally, before exposing the wafer to plasma, a plasma-resistant mask is formed on the wafer to protect devices mounted on it from the effects of the plasma. Specifically, for example, a liquid protective film is formed by coating the surface of the wafer with a liquid protective film agent, and then a laser beam of a wavelength absorbed by the protective film is irradiated along a predetermined processing line. Thus, by removing the portion of the protective film that overlaps with the predetermined processing line, a mask exposing the predetermined processing line can be formed.

[0011] However, when forming the aforementioned mask using the protective film agent currently available, the thickness of the peripheral portion (the edge portion of the mask) exposed to the laser beam is often uneven. Sometimes, the portion of the protective film exposed to the laser beam is not properly removed. Furthermore, when using such a substandard mask, it is difficult to maintain processing accuracy across the entire wafer.

[0012] Therefore, the object of the present invention is to provide a protective film agent capable of forming a protective film suitable for processing using a laser beam; and to provide a processing method for a workpiece using the protective film agent.

[0013] Methods for solving problems

[0014] According to one aspect of the present invention, a protective film agent is provided, which is applied to a workpiece during processing, comprising: a water-soluble resin; a light absorber having a flavonoid structure, a flavonol structure, or an isoflavone structure; and a solvent for dissolving the resin and the light absorber.

[0015] Preferably, the light absorber comprises a glycotransferase, and the solvent comprises water. Preferably, the glycotransferase is glycotransferrutin or glycotransferhesperidin. Preferably, the resin is polyvinyl alcohol, polyvinylpyrrolidone, hydroxypropyl cellulose, or polyoxazoline. Furthermore, it is preferred that the light absorber, when contained in an amount equivalent to a 200-fold dilution with water and measured at a thickness of 1 cm, has an absorbance of 5.0 or more at a wavelength of 355 nm.

[0016] According to another aspect of the present invention, a method for processing a workpiece is provided, comprising: a protective film forming step, wherein the aforementioned protective film agent is coated onto the surface of the workpiece to form a protective film; a mask forming step, wherein a laser beam of a wavelength absorbed by the protective film is irradiated along a predetermined processing line set on the surface of the workpiece, thereby removing the portion of the protective film overlapping with the predetermined processing line to form a mask; and a plasma etching step, wherein plasma is applied to the portion of the workpiece exposed from the mask, thereby removing the portion of the workpiece exposed from the mask.

[0017] According to another aspect of the present invention, a method for processing a workpiece is provided, comprising: a protective film forming step, wherein the aforementioned protective film agent is coated onto the surface of the workpiece to form a protective film; and a laser ablation step, wherein a laser beam of a wavelength absorbed by the protective film and the workpiece is irradiated along a predetermined processing line set on the surface of the workpiece, thereby removing the portion of the protective film overlapping with the predetermined processing line and the portion of the workpiece overlapping with the predetermined processing line.

[0018] Invention Effects

[0019] One aspect of the protective film agent of the present invention contains a light absorber having a flavonoid structure, a flavonol structure, or an isoflavone structure, and therefore, compared with existing protective film agents, it readily increases the absorbance at wavelengths in the ultraviolet region. Therefore, if a protective film is formed using this protective film agent, the protective film can be reliably processed using a laser beam with wavelengths in the ultraviolet region. Thus, according to one aspect of the present invention, a protective film agent is obtained that can form a protective film suitable for processing using a laser beam. Attached Figure Description

[0020] Figure 1 This is a perspective view showing an example of a workpiece coated with a protective film.

[0021] Figure 2 This is a cross-sectional view showing the case where the workpiece is coated with a protective film.

[0022] Figure 3 It is a cross-sectional view showing the state in which a protective film has been formed on the workpiece.

[0023] Figure 4 This is a cross-sectional view showing the application of a laser beam to the protective film.

[0024] Figure 5 It is a cross-sectional view showing the workpiece with a mask formed.

[0025] Figure 6 This is a cross-sectional view showing an example of a plasma etching apparatus.

[0026] Figure 7 This is a cross-sectional view showing the case where the workpiece is processed by plasma.

[0027] Figure 8 It is a cross-sectional view of the workpiece divided by the predetermined machining lines.

[0028] Figure 9 (A) is a photograph taken from above using a mask coated with the protective film agent of Example 1. Figure 9 (B) is a photograph taken from above using a mask coated with the protective film agent of Example 2. Figure 9 (C) is a photograph taken from above using a mask that has been fitted with the protective film agent of Example 3. Figure 9 (D) is a photograph taken from above using a mask with the protective film agent of Example 4. Figure 9 (E) is a photograph taken from above using a mask with the protective film agent of Example 5. Figure 9 (F) is a photograph taken from above using a mask with the protective film agent of Comparative Example 1.

[0029] Figure 10(A) is a photograph taken from an oblique angle of the workpiece that has been processed using a mask formed by the protective film agent of Example 1. Figure 10 (B) is a photograph taken from an oblique angle of view of the workpiece that has been processed using a mask formed by the protective film agent of Example 2. Figure 10 (C) is a photograph taken from an oblique angle of view of the workpiece that has been processed using a mask formed by the protective film agent of Example 3. Figure 10 (D) is a photograph taken from an oblique angle of view of the workpiece processed using a mask formed by the protective film agent of Example 4. Figure 10 (E) is a photograph taken from an oblique angle of view of the workpiece that has been processed using a mask formed by the protective film agent of Example 5. Figure 10 (F) is a photograph taken from an oblique angle of the workpiece that has been processed using a mask formed by the protective film agent of Comparative Example 1.

[0030] Figure 11 (A) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Example 1. Figure 11 (B) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Example 2. Figure 11 (C) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Example 3. Figure 11 (D) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Example 4. Figure 11 (E) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Example 5. Figure 11 (F) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Comparative Example 1.

[0031] Figure 12 This is a cross-sectional view showing the process of machining a workpiece using a laser beam. Detailed Implementation

[0032] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The protective film agent of this embodiment is used, for example, to coat a workpiece during processing. Figure 1 This is a perspective view showing an example of a workpiece 11 coated with the protective film agent of this embodiment.

[0033] like Figure 1As shown, the workpiece 11 in this embodiment is, for example, a wafer formed into a disk shape using a semiconductor such as silicon (Si), having a circular surface 11a and a circular back surface 11b opposite to the surface 11a. The surface 11a side of the workpiece 11 is divided into multiple small regions by multiple intersecting pre-defined processing lines (spacers) 13, and devices such as ICs (Integrated Circuits) 15 are formed in each small region.

[0034] A strip (scribing strip) 17, large enough to cover the entire back surface 11b, is attached to the workpiece 11. Furthermore, an annular frame 19 surrounding the workpiece 11 is fixed to the periphery of the strip 17. Thus, in this embodiment, the workpiece 11 and the annular frame 19 are integrated via the strip 17. However, when the workpiece 11 is coated with a protective film, the strip 17 and frame 19 are not necessarily required.

[0035] The protective film agent of this embodiment, which coats such processed material 11, typically includes a water-soluble resin, a light absorber capable of absorbing light of at least the wavelength (preferably 250 nm to 400 nm) in the ultraviolet region, and a solvent for dissolving the resin and the light absorber.

[0036] Water-soluble resins are, for example, polymeric compounds that can dissolve more than 0.5 g of 100 g of water at 25°C. Representative examples of such polymeric compounds include polyvinylpyrrolidone, polyvinyl alcohol, hydroxypropyl cellulose, hydroxypropyl methylcellulose, polyethylene glycol, polyethylene oxide, methylcellulose, ethylcellulose, polyacrylic acid, poly-N-vinylacetamide, polyglycerol, polyoxazoline (e.g., poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline), poly(2-propyl-2-oxazoline), etc.), poly(p-hydroxystyrene), polystyrene sulfonic acid, styrene maleic acid, and (meth)acrylic acid resins.

[0037] It should be noted that, as water-soluble resins, any one of these polymer compounds can be used alone, or multiple polymer compounds can be used in any combination. That is, the protective film agent can use only one water-soluble resin, or it can use a combination of two or more water-soluble resins. Furthermore, copolymers of these polymer compounds (polyvinyl alcohol-acrylic acid-methyl methacrylate copolymer, vinyl acetate-vinylpyrrolidone copolymer, ethylene-vinyl alcohol copolymer, polyvinyl alcohol-polyethylene glycol copolymer, etc.) are sometimes also used as water-soluble resins in the protective film agent.

[0038] Light absorbers are, for example, water-soluble compounds having a flavonoid, flavonol, or isoflavone structure. These compounds readily absorb light in the ultraviolet region, and are therefore suitable, for example, materials (protective film agents) for forming protective films (laser ablation processes) using a 355 nm laser beam. It should be noted that water-soluble compounds are, for example, compounds that can dissolve more than 0.5 g in 100 g of water at 25°C.

[0039] That is, the light absorber of this embodiment has, for example, the flavonoid structure shown in the following chemical formula (1). It should be noted that in chemical formula (1), R represents a hydrogen atom, a substituent, or a sugar chain.

[0040]

Chemistry 1

[0041]

[0042] Alternatively, the light absorber in this embodiment may have, for example, the flavonol structure shown in the following chemical formula (2). It should be noted that in chemical formula (2), R represents a hydrogen atom, a substituent, or a sugar chain.

[0043]

Chemistry 2

[0044]

[0045] Alternatively, the light absorber in this embodiment may have, for example, the isoflavone structure shown in the following chemical formula (3). It should be noted that in chemical formula (3), R represents a hydrogen atom, a substituent, or a sugar chain.

[0046]

Transformation 3

[0047]

[0048] Representative examples of such compounds include isorhamnetin, flavonols, 4'-hydroxyflavones, 5-hydroxyflavones, farnesin, baicalin, 3-hydroxy-4'-methoxyflavones, 7,8-dihydroxyflavones, icariin C, quercetin, baicalin, novohesperidin, fisetin, rutin, icariin, icariin, 7-hydroxyflavones, morin, kaempferol, hesperidin, 6-hydroxyflavones, kaempferol, baicalin, isohyperidin, 5-methoxyflavones, garciniacin, myricetin, 3-methylflavonoid-8-carboxylic acid, 6-methylflavones, apigenin, 3-methoxyflavones, baicalin, 3,4'-dihydroxyflavones, hornyperidin, 3',4' - Dihydroxyflavonoids, methyl hesperidin, succinate, 6-methoxyflavonoids, hesperidin, citronellol, galangin, flavonoids, isozygoside, diosmin, neodiosmin, troxerutin, 2-(2-amino-3-methoxyphenyl)chromone, flavonol-2'-sulfonic acid, flavonol ester, genistein, belamcanda chinensis glycoside, 4',6,7-trihydroxyisoflavone, epoetin, neopsoralen isoflavone, succinate glycoside, irisin, puerarin, chickpea sprout extract A, succinate, irisin, 7-methoxy-5-methylisoflavone, 4',6,7-trimethoxyisoflavone, daidzein, genistein, dihydrodaidzein, daidzein. However, other light absorbers can also be used in protective film agents.

[0049] To achieve high water solubility of the light absorber, the aforementioned compound used as the light absorber is preferably a glycotransferase. By using a glycotransferase as the light absorber, it is easy to increase the concentration of the light absorber in the protective film agent, thereby achieving high absorbance. Of course, other compounds can also be used as the light absorber.

[0050] Here, glycotransferomers are compounds bound with sugar chains, also known as glycosides. As long as the sugar chains are in a state that can impart water solubility to the above-mentioned compounds (substrate), they can be either monosaccharides or oligosaccharides (oligomers). Representative examples of such sugar chains include glucose, mannose, galactose, azurose, allose, talose, gulose, idulose, xylose, arabinose, ribose, lysolose, celeryose, erythrose, thioalose, fructose, allulose, sorbose, tagatose, ribulose, xylulose, erythrose, sedoheptulose, masalaose, glyceraldehyde, dihydroxyacetone, trehalose, isotrexose, kosmobiose, sophorose, aspergillus niger, laminarin, maltose, cellulobiose, isomaltose, gentiobiose, deoxyribose, fucose, rhamnose, glucosamine, galactosamine, glycerol, xylitol, sorbitol, glucuronic acid, galacturonic acid, ascorbic acid, glucuronide, gluconolactone, fructooligosaccharides, galactooligosaccharides, and lactulose oligosaccharides. Additionally, sugar chains can also be derivatives of these compounds.

[0051] Glycotransferases (i.e., glycotransferases having a flavonoid structure, a flavonol structure, or an isoflavone structure) that are particularly preferred as light absorbers in this embodiment are, for example, glycotransferrutin, glycotransfer hesperidin, etc.

[0052] It should be noted that, in addition to naturally occurring compounds, glycotransferomers also include compounds obtained through synthetic reactions. Synthetic reactions used to obtain glycotransferomers include, for example, chemical synthesis using artificial reagents and enzymatic synthesis using natural glycotransferases (proteins), selected according to the purpose. The glycotransferases that achieve sugar transfer are called glycosyltransferases, and depending on the type of sugar, fucosyltransferases, galactosyltransferases, sialyltransferases, dextrantransferases, etc., are used.

[0053] For example, compounds in which natural rutin, one of the flavonols, is endowed with two rutinose groups, and which are further endowed with sugar chains through enzymatic reactions, are also included in the above-mentioned glycotransferrutins. The same applies to glycotransferrohesperidin and other glycotransferomers (glycotransferomers with flavonoid, flavonol, or isoflavone structures).

[0054] Thus, by endowing the compound (substrate) with sugar chains containing numerous hydroxyl groups through glycotransferases, the solubility of the compound in water can be improved. Furthermore, by using highly water-soluble compounds such as glycotransferomers as light absorbers, the concentration of light absorbers in the protective film can be increased, achieving high absorbance.

[0055] Similarly, the compounds used as light absorbers preferably have polar groups (hydroxyl, ether, amine, carboxyl, amide, etc.) as substituents to achieve higher water solubility. By using such compounds as light absorbers, the concentration of light absorbers in the protective film can be increased, achieving high absorbance. Of course, compounds with other substituents can also be used as light absorbers.

[0056] It should be noted that any of the above-mentioned compounds can be used alone as a light absorber, or multiple compounds can be used in any combination. That is, a single light absorber can be used in the protective film agent, or two or more light absorbers can be used in combination. In addition, these light absorbers can also be mixed with light absorbers such as ferulic acid, caffeic acid, chlorogenic acid and other cinnamic acid derivatives, polyhydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid and other benzophenone derivatives.

[0057] The solvent is, for example, water. However, other solvents, such as organic solvents that are mixed with water, can also be used in the protective film agent. Examples of such organic solvents include propylene glycol monomethyl ether (PGME), methanol, ethanol, isopropanol, acetone, and tetrahydrofuran. It should be noted that a single organic solvent can be used in the protective film agent, or two or more organic solvents can be used in combination. On the other hand, in this embodiment, since a compound with high water solubility is used as the light absorber, the concentration of the light absorber in the protective film agent can be increased even without using a large amount of organic solvent, thus achieving high absorbance.

[0058] It should be noted that, in the protective film agent of this embodiment, an antioxidant may be added to inhibit its degradation over time. Representative examples of such antioxidants include L-ascorbic acid (i.e., vitamin C), D-arabinose-type ascorbic acid, ethyl ascorbic acid, and ascorbic acid 2-glucosidase. Any one of these antioxidants may be added to the protective film agent alone, or in any combination thereof.

[0059] Furthermore, in the protective film agent of this embodiment, a preservative may be added for the purpose of inhibiting corrosion. A representative example of such a preservative is methyl 4-hydroxybenzoate.

[0060] The contents of the water-soluble resin, light absorber, and solvent in the protective film agent can be arbitrarily set within a range that appropriately achieves the target performance of the protective film agent. Increasing the content of the water-soluble resin in the protective film agent easily increases the thickness of the protective film formed by the protective film agent. In addition, for water-soluble resins with the same structure, generally speaking, the smaller the molecular weight of the water-soluble resin, the easier it is to dissolve in the solvent, and the easier it is to reduce the viscosity for liquid transport while achieving the same concentration.

[0061] From the perspective of the thickness of the protective film and ease of liquid transport, the weight-average molecular weight of the water-soluble resin is preferably 250,000 or less, more preferably 100,000 or less. The light absorber can be contained in any amount, with its solubility as the upper limit, within the range that does not damage the target performance of the protective film agent. It should be noted that, in the case of glycotransferrutin (αG-rutin) manufactured by Toyo Seikan Co., Ltd., 50 parts by mass of glycotransferrutin can be dissolved in water.

[0062] Typically, the protective film agent is set to 100 parts by weight, the water-soluble resin content is 5 to 35 parts by weight, and the light absorber content is 1 to 25 parts by weight.

[0063] It should be noted that the protective film agent preferably contains an amount of light absorber having an absorbance of 5.0 or more per 1 cm thickness (along the length of the optical path) when the protective film agent is diluted 200 times with water. In other words, the protective film agent preferably contains an amount of light absorber having an absorbance of 5.0 or more per 1 cm thickness (along the length of the optical path) when the protective film agent is diluted 200 times with water. Thus, a protective film agent is obtained that can form a protective film suitable for processing with a laser beam having a wavelength of 355 nm.

[0064] Furthermore, the aforementioned protective film agent is preferably further processed through an ion exchange resin. This allows impurities such as metal ions to be removed from the protective film agent. It should be noted that, along with this ion exchange, the pH of the protective film agent reaches 4 or below. From a corrosion prevention perspective, a pH of 4 or below is preferred, but it is also possible to add a base such as triethanolamine to prepare the protective film agent with a pH of 4 or above.

[0065] The protective film agent described in this embodiment is used, for example, as a mask for plasma etching when the workpiece 11 is exposed to a highly reactive plasma for processing. In this workpiece processing method, a protective film agent is first coated on the surface 11a of the workpiece 11 to form a protective film (protective film formation step).

[0066] Figure 2 This is a cross-sectional view showing the case where the workpiece 11 is coated with a protective film agent 21. Figure 3 This is a cross-sectional view showing the state in which a protective film 23 has been formed on the workpiece 11. It should be noted that... Figure 2 and Figure 3 For ease of explanation, a portion of the elements are shown on the side. When the workpiece 11 is coated with a protective film agent 21, for example using... Figure 2 and Figure 3 The spin coater 2 shown.

[0067] The spin coater 2 includes a rotary table (holding table) 4 for holding the workpiece 11. The rotary table 4 is connected to a rotation drive source (not shown) such as an electric motor and rotates about a rotation axis that is substantially parallel to the vertical direction. A portion of the upper surface of the rotary table 4 is a holding surface 4a for holding the workpiece 11.

[0068] The holding surface 4a is connected to a suction source (not shown) such as a vacuum pump through a flow path (not shown) formed inside the rotary table 4. A nozzle 6 is arranged above the rotary table 4 for dripping a protective film agent 21, which is a material for the protective film 23. In addition, a plurality of clamps (not shown) are provided around the rotary table 4 for fixing the annular frame 19.

[0069] When the workpiece 11 is coated with the protective film agent 21 to form a protective film 23, the strip 17 attached to the back side 11b of the workpiece 11 is first brought into contact with the holding surface 4a of the rotary table 4, and a negative pressure from the suction source is applied. At the same time, the frame 19 is fixed with a clamp. As a result, the workpiece 11 is held with its surface 11a exposed upwards.

[0070] Next, as Figure 2 As shown, protective film agent 21 is dripped from nozzle 6 while the rotary table 4 is rotated, thus applying the protective film agent 21 to the surface 11a side of the workpiece 11. There are no particular restrictions on the conditions for applying the protective film agent 21. Typically, when the diameter of the workpiece 11 is 200 mm, the amount of protective film agent 21 dripped is 20 ml to 50 ml, the rotation speed of the rotary table 4 is 200 rpm to 3000 rpm, and the rotation time of the rotary table 4 is 30 seconds to 360 seconds.

[0071] Then, the protective film agent 21 coated on the surface 11a is dried, etc., thereby completing the process. Figure 3 The protective film 23 is shown. It should be noted that, in addition to natural drying, drying methods also include baking, xenon pulse irradiation, and infrared irradiation. By using methods such as baking, xenon pulse irradiation, and infrared irradiation, the protective film agent 21 can be rapidly dried to form the protective film 23.

[0072] It should be noted that in this embodiment, a protective film agent 21 is applied to the workpiece 11 by spin coating using the spin coater 2, but other methods such as spraying can also be used to apply the protective film agent 21 to the workpiece 11. It should be noted that spraying includes two-fluid spraying, ultrasonic atomization spraying, electrostatic spraying, etc. By using spin coating, a uniform protective film 23 can be easily formed over the entire workpiece 11, while by using spraying, a good protective film 23 can be formed even in cases where the surface 11a has large irregularities.

[0073] After a protective film 23 is formed on the surface 11a of the workpiece 11, a laser beam of wavelength absorbed by the protective film 23 is irradiated along a predetermined processing line 13 set on the surface 11a of the workpiece 11, thereby removing the portion of the protective film 23 that overlaps with the predetermined processing line 13 and forming a mask (mask forming step).

[0074] Figure 4 This is a cross-sectional view showing the situation where the protective film 23 is irradiated with the laser beam 25. Figure 5 This is a cross-sectional view showing the state in which the mask 27 is formed on the workpiece 11. It should be noted that... Figure 4 and Figure 5 For ease of explanation, a portion of the elements are also shown from the side. When the laser beam 25 is irradiated onto the protective film 23, for example using... Figure 4 and Figure 5 The laser processing device 12 shown.

[0075] The laser processing apparatus 12 includes a chuck table (holding table) 14 for holding the workpiece 11. The chuck table 14 is connected to a rotary drive source (not shown) such as an electric motor and rotates about a rotation axis that is substantially parallel to the vertical direction. In addition, a table moving mechanism (not shown) is provided below the chuck table 14, by which the chuck table 14 moves in the processing feed direction (first horizontal direction) and the indexing feed direction (second horizontal direction).

[0076] A portion of the upper surface of the chuck stage 14 serves as a holding surface 14a for holding the workpiece 11. This holding surface 14a is connected to a suction source (not shown) such as a vacuum pump via a flow path (not shown) formed inside the chuck stage 14. Multiple clamps (not shown) are provided around the chuck stage 14 for securing the annular frame 19.

[0077] Additionally, a processing head 16 of a laser irradiation unit is disposed above the chuck table 14. The laser irradiation unit uses the processing head 16 to focus a pulsed laser beam 25 generated by laser oscillation through a laser oscillator (not shown) at a predetermined position.

[0078] The laser oscillator is configured to generate a laser beam 25 with a wavelength absorbed by the protective film 23 formed using the protective film agent 21. The wavelength of the laser beam 25 generated by the laser oscillator is, for example, in the ultraviolet region (preferably 250 nm to 400 nm), typically 355 nm. However, there are no particular limitations on the wavelength of the laser beam 25 generated by the laser oscillator.

[0079] When the protective film 23 is irradiated with the laser beam 25 to form the mask 27, the strip 17 attached to the back side 11b of the workpiece 11 is first brought into contact with the holding surface 14a of the chuck table 14, applying negative pressure from the suction source. At the same time, the frame 19 is fixed with a clamp. As a result, the workpiece 11 is held with the protective film 23 on the covered surface 11a side exposed upwards.

[0080] Next, the chuck stage 14 is rotated so that the direction of the object machining predetermined line 13 extends is aligned with the machining feed direction of the laser processing apparatus 12. Additionally, the chuck stage 14 is moved, for example, so that the position of the processing head 16 of the laser irradiation unit is aligned above the extension line of the object machining predetermined line 13.

[0081] Then, as Figure 4 As shown, while irradiating the workpiece 11 surface 11a side of the workpiece 11 from the processing head 16 of the laser irradiation unit, the chuck stage 14 is moved along the processing feed direction. Here, for example, the laser beam 25 is focused on the surface or interior of the protective film 23.

[0082] The power of the laser beam 25 is set, for example, from 0.1W to 100W, typically 0.5W. The spot diameter on the surface of the object (protective film 23) is adjusted, for example, from 1μm to 100μm, typically from 5μm to 15μm. The repetition frequency is set, for example, from 100kHz to 50000kHz, typically from 100kHz to 1000kHz. The pulse width is set, for example, from 10 femtoseconds to 500 nanoseconds, typically from 3 picoseconds to 30 picoseconds. The moving speed of the chuck stage 14 is set, for example, from 20mm / s to 5000mm / s, typically from 20mm / s to 1000mm / s. However, there are no particular limitations on the conditions for irradiating the laser beam 25. In addition, in this embodiment, the laser beam 25 is irradiated under conditions where the workpiece 11 has hardly been processed, but the laser beam 25 can also be used to partially process the workpiece 11.

[0083] Therefore, the laser beam 25 can be irradiated along the predetermined processing line 13 to remove the portion of the protective film 23 that overlaps with the predetermined processing line 13. This operation is repeated to remove all portions of the protective film 23 that overlap with the predetermined processing lines 13, thereby obtaining an area covering the device 15 corresponding to the workpiece 11. Figure 5 Mask 27 is shown.

[0084] In this embodiment, as described above, a protective film 23 is formed using a protective film agent 21, which contains a light absorber suitable for achieving high absorbance at wavelengths in the ultraviolet region. Therefore, the laser beam 25 can be sufficiently absorbed into the protective film 23, appropriately removing a portion of the object from the protective film 23. Furthermore, the thickness deviation of the peripheral portion (edge ​​portion of the mask 27) of the portion irradiated by the laser beam 25 is also reduced.

[0085] After forming a mask 27 covering the workpiece 11, plasma is applied to the workpiece 11 through the mask 27 to process the portion of the workpiece 11 exposed from the mask 27 (plasma etching step). Figure 6 This is a cross-sectional view showing the plasma etching apparatus 22. Figure 7 This is a cross-sectional view showing the process of processing the workpiece 11 via plasma 29. It should be noted that... Figure 6 For ease of explanation, some elements of the plasma etching apparatus 22 are represented by symbols and functional blocks. Figure 7 The image shows a partial view of some of the elements.

[0086] When processing the workpiece 11 using plasma 29, for example using Figure 6The plasma etching apparatus 22 shown is a vacuum chamber 24 with a processing space inside. An opening 24a of a size for the workpiece 11 and the frame 19 to pass through is formed on the side wall of the vacuum chamber 24. A cover 26 of a size that can cover the opening 24a is provided outside the opening 24a.

[0087] The cover 26 is connected to an opening and closing mechanism (not shown) for opening and closing the cover 26. Opening the cover 26 exposes the opening 24a, through which the workpiece 11 can be moved into the interior space of the vacuum chamber 24, or the workpiece 11 can be moved out of the interior space of the vacuum chamber 24.

[0088] An exhaust port 24b is formed on the bottom wall of the vacuum chamber 24. This exhaust port 24b is connected to an exhaust unit 28, such as a vacuum pump. A lower electrode 30 is disposed within the space of the vacuum chamber 24. The lower electrode 30 is formed into a disk shape using a conductive material and is connected to a high-frequency power supply 32 outside the vacuum chamber 24.

[0089] An electrostatic chuck 34 is disposed on the upper surface of the lower electrode 30. The electrostatic chuck 34, for example, includes mutually insulated electrodes 36a and 36b, and holds the workpiece 11 by an electric current acting between electrodes 36a and 36b and the workpiece 11. For example, it is configured to connect the positive terminal of a DC power supply 38a to electrode 36a, and to connect the negative terminal of a DC power supply 38b to electrode 36b. It should be noted that the DC power supply 38a and DC power supply 38b can be the same DC power supply.

[0090] An upper electrode 40, formed into a disk shape using a conductive material, is mounted on the top wall of the vacuum chamber 24 via an insulating component 42. Multiple gas ejection holes 40a are formed on the lower surface of the upper electrode 40, and these gas ejection holes 40a are connected to a gas supply source 44 via gas supply holes 40b and the like, which are located on the upper surface of the upper electrode 40. This allows gas for plasma etching to be supplied from the gas supply source 44 into the space of the vacuum chamber 24. The upper electrode 40 is also connected to a high-frequency power supply 46 outside the vacuum chamber 24.

[0091] When processing the workpiece 11 using plasma 29, the cover 26 is first opened using the opening and closing mechanism. Next, the workpiece 11 is moved into the space of the vacuum chamber 24 through the opening 24a and placed on the electrostatic chuck 34. Specifically, the strip 17 attached to the back side 11b of the workpiece 11 is brought into contact with the upper surface of the electrostatic chuck 34. Afterwards, when the electrostatic chuck 34 is operated, the workpiece 11 is held with the mask 27 on the surface 11a side exposed upwards.

[0092] After holding the workpiece 11 in the electrostatic chuck 34, plasma 29 is applied to the workpiece 11 through the mask 27, thereby processing the workpiece 11 along the predetermined processing line 13. Specifically, the cover 26 is first closed by the opening and closing mechanism to seal the space of the vacuum chamber 24.

[0093] Additionally, the exhaust unit 28 is operated to depressurize the space within the vacuum chamber 24. In this state, while supplying plasma etching gas from the gas supply source 44 at a predetermined flow rate, appropriate high-frequency power is supplied to the lower electrode 30 and upper electrode 40 using high-frequency power supplies 32 and 46, as follows: Figure 7 As shown, a plasma 29 containing free radicals, ions, etc. is generated between the lower electrode 30 and the upper electrode 40.

[0094] Thus, the surface 11a side of the workpiece 11 not covered by the mask 27 (i.e., the processing predetermined line 13) is exposed to the plasma 29, enabling the workpiece 11 to be processed. It should be noted that the plasma etching gas supplied from the gas supply source 44 is appropriately selected according to the material of the workpiece 11, etc.

[0095] For example, if it is desired to process the workpiece 11 deeper along the thickness direction, as when dividing the workpiece 11 along the predetermined processing line 13, the three steps of trench formation, film formation, and partial film removal can be repeated. When a wafer formed of silicon is used as the workpiece 11, the following applies.

[0096] In the tank formation step, for example, the pressure within the vacuum chamber 24 is kept constant, while SF6 is supplied from the gas supply source 44 at a predetermined flow rate, and a predetermined high-frequency power is supplied to the lower electrode 30 and the upper electrode 40. This allows, for example, the generation of a plasma 29 containing free radicals, ions, etc., based on SF6, to process the portion of the workpiece 11 not covered by the mask 27 on the surface 11a side. As a result, such as... Figure 7 As shown, a shallow groove 31 is formed on the predetermined processing line 13 of the workpiece 11.

[0097] In the film formation step, for example, the pressure inside the vacuum chamber 24 is kept constant, while C4F8 is supplied from the gas supply source 44 at a specified flow rate, and a specified high-frequency power is supplied to the lower electrode 30 and the upper electrode 40. As a result, a fluorine-based material can be deposited inside the groove 31 formed in the above-described groove formation step, forming a thin film (not shown) covering the inner surface of the groove 31. The film formed from this fluorine-based material exhibits specific resistance to plasma 29 generated using SF6 as a raw material.

[0098] In the partial film removal step, for example, the pressure inside the vacuum chamber 24 is kept constant, while SF6 is supplied from the gas supply source 44 at a specified flow rate, and a specified high-frequency power is supplied to the lower electrode 30 and the upper electrode 40. It should be noted that in this partial film removal step, the power supplied to the lower electrode 30 is increased compared to the trench formation step.

[0099] If the power supplied to the lower electrode 30 is increased, the anisotropy of the etching performed using plasma 29 is improved. Specifically, the portion of the film covering the trench 31 on the lower electrode 30 side (i.e., the bottom surface side of the trench 31) is preferentially processed. That is, by using plasma 29 generated from SF6, it is possible to remove only the portion of the film covering the trench 31 on the bottom surface of the trench 31.

[0100] By repeating the three steps of groove formation, film formation, and partial film removal, the groove 31 gradually becomes deeper and can eventually divide the workpiece 11 along the predetermined processing line 13. Figure 8 This is a schematic cross-sectional view of the workpiece 11 divided by the machining predetermined line 13. It should be noted that... Figure 8 For ease of explanation, some aspects of the elements are also shown. For example... Figure 8 As shown, if the workpiece 11 is divided using the pre-defined processing line 13, multiple chips 33 are obtained.

[0101] It should be noted that after processing the workpiece 11 with plasma 29, the protective film 23 can be removed by a two-fluid cleaning method such as jet cleaning with a mixture of water and air. As described above, by using a light absorber with high water solubility in the protective film agent 21, the protective film 23 can be removed simply and reliably by a two-fluid cleaning method with water. That is, compared with using a light absorber with high affinity for organic solvents, it is less likely to leave residues caused by the light absorber.

[0102] Besides two-fluid cleaning, methods for removing the protective film 23 include high-pressure cleaning, steam two-fluid cleaning, and micro / nano-scale bubble water cleaning. Furthermore, in these cleaning methods, room temperature water (cleaning water) or heated water can be used. Additionally, in cases where the protective film is difficult to remove with water alone, it can be removed from the workpiece by using plasma treatment, ultraviolet light (e.g., wavelengths of 185 nm and / or 254 nm), excimer laser (e.g., wavelength of 172 nm) irradiation, or cleaning with ozone water.

[0103] As described above, the protective film agent 21 of this embodiment contains a light absorber having a flavonoid structure, a flavonol structure, or an isoflavone structure, and therefore, compared with conventional protective film agents, it is easier to increase the absorbance of wavelengths in the ultraviolet region. Therefore, if the protective film 23 is formed using this protective film agent 21, the protective film 23 can be reliably processed using a laser beam 25 having a wavelength in the ultraviolet region.

[0104] Furthermore, in the workpiece processing method of this embodiment, since the protective film 23 is processed to form a plasma etching mask 27, the predetermined processing line 13 of the workpiece 11 is appropriately exposed from the mask 27, and the thickness deviation of the edge portion of the mask 27 is also reduced. As a result, the processing accuracy performed by plasma etching can be maintained at a high level throughout the workpiece 11.

[0105] Next, the experiments conducted to confirm the effectiveness of the aforementioned protective film agent and the results will be described. First, several protective film agents with different types of water-soluble resins and different contents of light absorbers were prepared (Examples 1-5). In addition, a conventional protective film agent without the light absorber of this embodiment was prepared (Comparative Example 1).

[0106] [Example 1]

[0107] Three parts by mass of α-rutin (manufactured by Toyo Seikan Corporation), serving as a light absorber, were slowly added to 78 parts by mass of water (pure water) as a solvent, and the mixture was stirred until dissolved. Then, 19 parts by mass of hydroxypropyl cellulose (hereinafter referred to as HPC), serving as a water-soluble resin, were slowly added and stirred until dissolved, thereby obtaining the protective film agent of Example 1. It should be noted that the molecular weight of this HPC is 40,000.

[0108] [Example 2]

[0109] In the process of preparing the protective film agent of Example 1, αG rutin was reduced to 6 parts by mass and HPC was reduced to 16 parts by mass. The protective film agent of Example 2 was obtained by following the same process.

[0110] [Example 3]

[0111] In the process of preparing the protective film agent of Example 1, water was reduced to 75 parts by mass, αG rutin was reduced to 12.5 parts by mass, HPC was reduced to 12.5 parts by mass, and the protective film agent of Example 3 was obtained by following the same process.

[0112] [Example 4]

[0113] Six parts by mass of α-G-rutin, serving as a light absorber, were slowly added to 78 parts by mass of water as a solvent, and the mixture was stirred until dissolved. Then, 16 parts by mass of polyvinyl alcohol (hereinafter referred to as PVA), serving as a water-soluble resin, were slowly added, and the mixture was stirred until dissolved, thereby obtaining the protective film agent of Example 4. It should be noted that the degree of polymerization of this PVA is 300, and the degree of saponification is 78.5%–81.5 mol%.

[0114] [Example 5]

[0115] Six parts by mass of αG-rutin, serving as a light absorber, were slowly added to 78 parts by mass of water as a solvent, and the mixture was stirred until dissolved. Then, 16 parts by mass of polyvinylpyrrolidone (hereinafter referred to as PVP), serving as a water-soluble resin, were slowly added, and the mixture was stirred until dissolved, thereby obtaining the protective film agent of Example 5. It should be noted that the K value of this PVP is 48–52 (K-50).

[0116] [Comparative Example 1]

[0117] 20.56 parts by weight of PVP were slowly added to 64.35 parts by weight of water and stirred until dissolved to obtain the first solution. Separately, 0.3 parts by weight of ferulic acid as a light absorber were dissolved in 14.79 parts by weight of propylene glycol monomethyl ether (hereinafter referred to as PGME) to obtain the second solution. Then, the first and second solutions were mixed, and 0.0012 parts by weight of ascorbic acid was further added to obtain the protective film agent of Comparative Example 1.

[0118] The composition ratios (mass ratios) of each protective film agent (Examples 1-5 and Comparative Example 1) are shown in Tables 1 and 2. It should be noted that the specific materials are shown in parentheses in Tables 1 and 2.

[0119] Table 1

[0120]

[0121] Table 2

[0122]

[0123] [Measurement of absorbance]

[0124] After preparing the aforementioned protective film agents, the absorbance of each protective film agent at a wavelength of 355 nm per 1 cm thickness was measured using a UV-Vis spectrophotometer (Shimadzu UV-2700). Specifically, the protective film agents of each example and comparative example were diluted with water (pure water), and the resulting solutions were sealed in quartz prismatic cuvettes. The absorption spectrum of each protective film agent was then measured while sealed in the cuvettes. The thickness of the cuvettes (along the length of the light path) was 1 cm.

[0125] It should be noted that, in relation to the measurement limits of the spectrophotometer, the absorbance of the protective film agent of Example 1 and Comparative Example 1 was measured when diluted 200 times with water (pure water); the absorbance of the protective film agent of Example 2, Example 4 and Example 5 was measured when diluted 400 times with water; and the absorbance of the protective film agent of Example 3 was measured when diluted 800 times with water.

[0126] The absorbance measurement results are shown in Table 3. It should be noted that Table 3 shows the absorbance of each protective film agent converted to a state of 200 times dilution with water.

[0127] Table 3

[0128] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 absorbance 3.192 6.452 13.20 6.420 6.430 0.166

[0129] [Formation of a protective film]

[0130] Using the aforementioned protective film agent, a protective film is formed by spin coating onto the workpiece. Regarding the rotation speed of the rotary table, it was set to 1000 rpm in Example 4, and 2000 rpm elsewhere. The rotation time of the rotary table was set to 90 seconds. Furthermore, the film thickness of each protective film was measured using a film thickness gauge (Filmetrics F50). The measurement results are shown in Table 4.

[0131] Table 4

[0132] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Film thickness (μm) 4.27 4.01 4.15 3.59 3.94 3.77

[0133] [Mask Formation]

[0134] A protective film obtained using a protective film agent is processed using a 355nm laser beam to form a mask exposing the predetermined processing lines of the workpiece. Here, the laser beam power is set to 0.5W, the spot diameter on the surface of the protective film is adjusted to 5μm to 10μm, the repetition frequency is set to 200kHz, the pulse width is set to 9 picoseconds, and the chuck stage movement speed is set to 600mm / s.

[0135] Then, the masks were photographed from above. Figure 9 (A) is a photograph taken from above using a mask coated with the protective film agent of Example 1. Figure 9 (B) is a photograph taken from above using a mask coated with the protective film agent of Example 2. Figure 9 (C) is a photograph taken from above using a mask that has been fitted with the protective film agent of Example 3. Figure 9 (D) is a photograph taken from above using a mask with the protective film agent of Example 4. Figure 9(E) is a photograph taken from above using a mask with the protective film agent of Example 5. Figure 9 (F) is a photograph taken from above using a mask with the protective film agent of Comparative Example 1.

[0136] Depend on Figure 9 (A) Figure 9 (B) Figure 9 (C) Figure 9 (D) and Figure 9 (E) and Figure 9 A comparison of (F) shows that the masks using the protective film agents of Examples 1-5 ( Figure 9 (A) Figure 9 (B) Figure 9 (C) Figure 9 (D) and Figure 9 In the case of (E), compared with the mask using the protective film agent of Comparative Example 1 ( Figure 9 Compared to (F), the bulge at the edge of the mask is reduced. That is, the thickness deviation at the edge of the mask is reduced.

[0137] In addition, by Figure 9 (A) Figure 9 (B) and Figure 9 A comparison of (C) shows that the masks using the protective film agents of Examples 1-3 (( Figure 9 (A) Figure 9 (B) and Figure 9 In case (C), as the content of the light absorber increases, the bulge at the edge of the mask decreases. That is, as the content of the light absorber increases, the thickness deviation at the edge of the mask decreases.

[0138] [Processing of the workpiece]

[0139] Using the mask obtained as described above, plasma is used to process the portion of the workpiece exposed from the mask. It should be noted that the workpiece is a wafer formed using silicon. Furthermore, when exposing the workpiece to plasma, the method of repeating the three steps of trench formation, film formation, and partial film removal described above is applied.

[0140] Then, the processed workpiece is photographed from an oblique angle above while the mask remains on its surface. Figure 10 (A) is a photograph taken from an oblique angle of the workpiece that has been processed using a mask formed by the protective film agent of Example 1. Figure 10 (B) is a photograph taken from an oblique angle of view of the workpiece that has been processed using a mask formed by the protective film agent of Example 2. Figure 10(C) is a photograph taken from an oblique angle of view of the workpiece that has been processed using a mask formed by the protective film agent of Example 3. Figure 10 (D) is a photograph taken from an oblique angle of view of the workpiece processed using a mask formed by the protective film agent of Example 4. Figure 10 (E) is a photograph taken from an oblique angle of view of the workpiece that has been processed using a mask formed by the protective film agent of Example 5. Figure 10 (F) is a photograph taken from an oblique angle of the workpiece that has been processed using a mask formed by the protective film agent of Comparative Example 1.

[0141] Additionally, the processed workpiece is photographed from the side while the mask remains on its surface. That is, the side of the workpiece processed by plasma is photographed. Figure 11 (A) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Example 1. Figure 11 (B) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Example 2. Figure 11 (C) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Example 3. Figure 11 (D) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Example 4. Figure 11 (E) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Example 5. Figure 11 (F) is a photograph taken from the side of the workpiece that has been processed using a mask formed by the protective film agent of Comparative Example 1.

[0142] Depend on Figure 10 (A) Figure 10 (B) Figure 10 (C) Figure 10 (D) and Figure 10 (E) and Figure 10 A comparison of (F) shows that the mask formed by the protective film agent of Comparative Example 1 (F) Figure 10 In (F), even after the workpiece has been processed, a large bulge remains at the edge of the mask. That is, during plasma processing, the thickness deviation of the mask edge continuously affects the processing accuracy of the workpiece.

[0143] In addition, by Figure 11 (A) Figure 11 (B) Figure 11 (C) Figure 11 (D) and Figure 11 (E) and Figure 11 A comparison of (F) shows that the side surface of the workpiece processed using a mask formed by the protective film agent of Comparative Example 1 (F) Figure 11 Due to thickness deviations at the edges of the mask, linear defects extending in the thickness direction of the workpiece (processing unevenness) occur. On the other hand, the side surfaces of the workpiece processed using the protective film agents of Examples 1-5... Figure 11 (A) Figure 11 (B) Figure 11 (C) Figure 11 (D) and Figure 11 (E)) did not produce this linear defect.

[0144] As described above, it has been confirmed that by using the protective film agent of this embodiment, a protective film suitable for processing with a laser beam can be formed, and the processing accuracy of the workpiece can be maintained at a high level.

[0145] Incidentally, it was confirmed that even with existing protective film agents that do not use the light absorber of this embodiment, when the organic solvent content is increased, the absorbance at a wavelength of 355 nm can be increased to approximately 4.0 per 1 cm thickness when diluted with water by 200 times. For example, for the protective film agent of Comparative Example 2 obtained in this way, the absorbance at a wavelength of 355 nm per 1 cm thickness when diluted with water by 200 times is 4.048.

[0146] [Comparative Example 2]

[0147] 21 parts by mass of PVP were slowly added to 57 parts by mass of water and stirred until dissolved to obtain the first solution. Separately, 2 parts by mass of 2,2',4,4'-tetrahydroxybenzophenone, acting as a light absorber, were dissolved in 20 parts by mass of PGME to obtain the second solution. The first and second solutions were then mixed to obtain the protective film agent of Comparative Example 2.

[0148] Therefore, from the perspective of achieving higher absorbance than existing protective film agents, it is preferable that the protective film agent contains a light absorber in an amount equivalent to an absorbance of 5.0 or more per 1 cm thickness at a wavelength of 355 nm when diluted 200 times with water. Furthermore, it is more preferable that the protective film agent contains a light absorber in an amount equivalent to an absorbance of 10 or more per 1 cm thickness at a wavelength of 355 nm when diluted 200 times with water.

[0149] However, if the content of organic solvent is increased to increase the content of light absorber, as mentioned above, residue caused by the light absorber is easily left behind. Furthermore, increasing the content of organic solvent can easily lead to problems such as reduced safety and deterioration of the adhesive layer of the scribe line. From the perspective of solving these problems, it is sufficient that the protective film agent at least contains the light absorber of this embodiment. That is, there are no restrictions on the lower or upper limits of the content of the light absorber constituting the protective film agent of this embodiment.

[0150] It should be noted that the present invention is not limited to the embodiments and examples described above, and can be implemented with various modifications. For example, in the workpiece processing method of the above embodiments, a protective film agent 21 is used to form a mask 27 for plasma etching, but the protective film agent 21 can also be used in workpiece processing methods using laser ablation, etc.

[0151] In the processing method of this modified example, a protective film 23 is first formed by coating the surface 11a of the workpiece 11 with a protective film agent 21 (protective film forming step). The specific process for forming the protective film 23 is the same as that for forming the protective film 23 using the processing method of the workpiece described above.

[0152] After a protective film 23 is formed on the surface 11a of the workpiece 11, a laser beam of wavelength absorbed by both the protective film 23 and the workpiece 11 is irradiated along the predetermined processing line 13 set on the surface 11a of the workpiece 11, thereby removing the portion of the protective film 23 that overlaps with the predetermined processing line 13 and the portion of the workpiece 11 that overlaps with the predetermined processing line 13 (laser ablation step).

[0153] Figure 12 This is a cross-sectional view showing the case where the workpiece 11 is processed by the laser beam 35. It should be noted that... Figure 12 For ease of explanation, a portion of the elements are also shown from the side. The laser processing apparatus 12 described above can also be used when the protective film 23 and the workpiece 11 are irradiated with the laser beam 35.

[0154] However, in this modified example, a laser oscillator (not shown) is used, which is capable of generating a laser beam 35 with a wavelength in the ultraviolet region that is absorbed by both the protective film 23 and the workpiece 11. That is, the wavelength of the laser beam 35 generated by the laser oscillator is in the ultraviolet region (preferably 250 nm to 400 nm), typically 355 nm.

[0155] The process of processing the protective film 23 and the workpiece 11 by irradiating the protective film 23 with the laser beam 25 is the same as the process of forming the mask 27 by irradiating the protective film 23 with the laser beam 25. It should be noted that in this modified example, the laser beam 35 can be focused onto the surface 11a or the interior of the workpiece 11.

[0156] The power of the laser beam 35 is set, for example, from 0.1W to 100W, typically from 0.5W to 15W. The spot diameter on the surface of the object (e.g., the protective film 23) is adjusted, for example, from 1μm to 100μm, typically from 30μm to 60μm. The pulse width is set, for example, from 10 femtoseconds to 500 nanoseconds. The repetition frequency is set, for example, from 20kHz to 50000kHz, typically from 20kHz to 2000kHz. The moving speed of the chuck stage 14 is set, for example, from 20mm / s to 5000mm / s, typically from 100mm / s to 1000mm / s. It should be noted that in this modified example, the laser beam 35 is irradiated while processing both the protective film 23 and the workpiece 11. This allows the portions of the protective film 23 and the workpiece 11 that overlap with the predetermined processing line 13 to be removed.

[0157] In addition, the above-described embodiments, variations, structures, methods, etc., can be appropriately modified to implement them as long as they do not depart from the scope of the present invention.

[0158] Symbol Explanation

[0159] 2: Spin coater

[0160] 4: Rotary table (holding table)

[0161] 4a: Maintain surface

[0162] 6: Nozzle

[0163] 12: Laser processing equipment

[0164] 14: Chuck stage (holding stage)

[0165] 14a: Maintain surface

[0166] 16: Processing head

[0167] 22: Plasma Etching Device

[0168] 24: Vacuum Chamber

[0169] 24a: Open

[0170] 24b: Exhaust port

[0171] 26: Cover

[0172] 28: Exhaust unit

[0173] 30: Lower electrode

[0174] 32: High-frequency power supply

[0175] 34: Electrostatic Chuck

[0176] 36a: Electrode

[0177] 36b: Electrode

[0178] 38a: DC power supply

[0179] 38b: DC power supply

[0180] 40: Upper electrode

[0181] 40a: Gas ejection port

[0182] 40b: Gas supply port

[0183] 42: Insulating components

[0184] 44: Gas supply source

[0185] 46: High-frequency power supply

[0186] 11: Workpiece

[0187] 11a: Surface

[0188] 11b: Back

[0189] 13: Processing pre-order line (interval channel)

[0190] 15: Devices

[0191] 17: Belt (Cut Strip)

[0192] 19: Framework

[0193] 21: Protective film agent

[0194] 23: Protective film

[0195] 25: Laser beam

[0196] 27: Mask

[0197] 29: Plasma

[0198] 31: slot

[0199] 33: Chip

[0200] 35: Laser beam

Claims

1. A protective film agent, which is applied to a workpiece during processing, comprising: Water-soluble resins; Light absorbers having flavonoid, flavonol, or isoflavone structures; and The solvent that dissolves the resin and the light absorber. The light absorber contains a glycotransferase, and the solvent contains water. The glycotransferosome is glycotransferrutin or glycotransferhesperidin.

2. The protective film agent of claim 1, wherein, The resin is polyvinyl alcohol, polyvinylpyrrolidone, hydroxypropyl cellulose, or polyoxazoline.

3. The protective film agent as described in claim 1 or 2, comprising an amount of light absorber having an absorbance of 5.0 or more at a wavelength of 355 nm when converted to a state of 200 times dilution with water and measured at a thickness of 1 cm.

4. A method for processing a workpiece, comprising: The protective film forming step involves coating the surface of the workpiece with a protective film agent to form a protective film, the protective film agent comprising: a water-soluble resin; A light absorber having a flavonoid structure, a flavonol structure, or an isoflavone structure; and a solvent for dissolving the resin and the light absorber; In the mask forming step, a laser beam of a wavelength absorbed by the protective film is irradiated along a predetermined processing line set on the surface of the workpiece, thereby removing the portion of the protective film that overlaps with the predetermined processing line and forming a mask. and The plasma etching step involves applying plasma to the portion of the workpiece exposed from the mask, thereby removing that portion. The light absorber contains a glycotransferase, and the solvent contains water. The glycotransferosome is glycotransferrutin or glycotransferhesperidin.

5. The method of processing a workpiece as recited in claim 4, wherein, The resin is polyvinyl alcohol, polyvinylpyrrolidone, hydroxypropyl cellulose, or polyoxazoline.

6. The method of processing a workpiece according to claim 4 or 5, wherein, The protective film agent contains a light absorber with an absorbance of 5.0 or more at a wavelength of 355 nm when the absorbance is measured at a thickness of 1 cm after being diluted 200 times with water.

7. A method for processing a workpiece, comprising: The protective film forming step involves coating the surface of a workpiece with a protective film agent to form a protective film, the protective film agent comprising: a water-soluble resin; a light absorber having a flavonoid structure, a flavonol structure, or an isoflavone structure; and a solvent for dissolving the resin and the light absorber; and In the laser ablation step, a laser beam of wavelength absorbed by the protective film and the workpiece is irradiated along a predetermined processing line set on the surface of the workpiece, thereby removing the portion of the protective film overlapping the predetermined processing line and the portion of the workpiece overlapping the predetermined processing line. The light absorber contains a glycotransferase, and the solvent contains water. The glycotransferosome is glycotransferrutin or glycotransferhesperidin.

8. The method of processing a workpiece as recited in claim 7, wherein, The resin is polyvinyl alcohol, polyvinylpyrrolidone, hydroxypropyl cellulose, or polyoxazoline.

9. The method of processing a workpiece according to claim 7 or 8, wherein, The protective film agent contains a light absorber with an absorbance of 5.0 or more at a wavelength of 355 nm when the absorbance is measured at a thickness of 1 cm after being diluted 200 times with water.

Images