Light absorber, laser protective solution containing the same, and method for preparing the same

Abstract

The application provides a light absorber, a laser protection liquid containing the light absorber and a preparation method of the laser protection liquid. The light absorber contains an organic fluorine boron complex or a salt thereof; wherein the organic fluorine boron complex has the following structure: The light absorber of the application has an absorption peak in the visible light region and the ultraviolet region. Moreover, the light absorber of the application is water-soluble after being salified, can be dissolved in water, does not need to add a pH regulator or a complexing agent to help dissolution, and effectively avoids corrosion of a chip.

Description

Technical Field

[0001] This invention relates to a light absorber, a laser protective liquid containing the light absorber, and a method for preparing the same, belonging to the field of semiconductor device manufacturing. Background Technology

[0002] With the rapid development of consumer electronics and computer networks, the integrated circuit industry has grown rapidly, and the size requirements for integrated circuit products with specific electrical functions are becoming increasingly precise. Integrated circuit products are made by adding various circuit element structures to silicon wafers, which are cut from single-crystal silicon ingots, to achieve specific electrical functions. The development of smaller integrated circuits places higher demands on the technological windows of chip design, photolithography, and other processes, and also brings significant challenges to subsequent cutting and packaging technologies. Among these, the maturity of the cutting process in the later stages has a significant impact on product yield.

[0003] Currently, the semiconductor industry typically uses two methods for dicing silicon wafers: diamond blade cutting and laser cutting. As the size of semiconductor integrated circuits continues to shrink, the kerf size is also gradually decreasing. This means that during the cutting process, flying debris or deposited vapor can contaminate functional areas and affect the circuitry. Furthermore, the high temperatures during laser cutting can cause metal circuitry to oxidize and fail, or even wafer chipping. To avoid these problems and improve the yield and cutting efficiency of semiconductor products, a laser cutting protective solution needs to be coated onto the substrate surface to form a protective film before laser processing.

[0004] Besides preventing contamination of functional areas by splashed debris or deposited impurities, and possessing functions such as heat absorption, oxidation prevention, corrosion resistance, and easy cleaning, laser protective fluids also need to have appropriate laser absorption properties. Otherwise, the silicon substrate will melt before the protective film, and the unbroken protective film may tear the functional areas. Therefore, the selection of laser absorbers must also meet appropriate conditions during the development of laser protective fluids. Lasers used for cutting semiconductors can currently be classified by wavelength into ultraviolet lasers, green lasers, and infrared lasers. Existing laser protective fluids often only absorb specific wavelengths of laser light, such as 355nm ultraviolet light. When the wavelength of the cutting laser is changed, existing laser protective fluids lose their ability to absorb both thermal and optical energy, resulting in poorer cutting performance.

[0005] Several laser protective solutions have been disclosed. For example, CN113814575A discloses a laser cutting protective solution, its preparation method, and its application. The laser cutting protective solution comprises a combination of water-soluble resin, azeotropic solvent, polyol, water-soluble ultraviolet absorber, water-soluble antioxidant, pH adjuster, and corrosion inhibitor. By using an azeotropic solvent and adding polyol, water-soluble ultraviolet absorber, and water-soluble antioxidant, the laser cutting protective solution utilizes the synergistic effect of each component to solve the problem of severe carbonization residue after use of existing cutting protective solutions, thus helping to improve the optoelectronic performance of chips.

[0006] CN112898853A discloses a laser cutting protective fluid for semiconductor cutting, its preparation method, and its application. The laser cutting protective fluid comprises the following components by weight percentage: 1-20% water-soluble resin, 1-30% solvent, 0.5-5% humectant, 0.1-1% water-soluble UV absorber, 0.1-0.5% water-soluble antioxidant, 2-10% water-soluble red pigment, 1-2% pH adjuster, 0.1-0.2% corrosion inhibitor, and water to 100%. This laser cutting protective fluid exhibits excellent heat resistance, can meet various laser cutting protection application requirements, and can save on equipment and material costs.

[0007] However, existing laser protective solutions suffer from problems such as inapplicability to multiple light sources and chip metal corrosion. Therefore, researching a light absorber that is suitable for multiple light sources, can be applied to both 355nm ultraviolet lasers and 532nm green lasers, and can be used in laser protective solutions has become an urgent technical problem to be solved. Summary of the Invention

[0008] The problem the invention aims to solve

[0009] In view of the technical problems existing in the prior art, the present invention first provides a light absorber. The light absorber of the present invention has absorption peaks in both the visible light region and the ultraviolet light region.

[0010] Furthermore, the present invention also provides a laser protective liquid that can be applied to the wafer cutting process of both ultraviolet laser and green laser in the semiconductor field, solving the problem of needing to change the matching protective liquid when changing the cutting laser and reducing the cost of process change.

[0011] Furthermore, the present invention also provides a method for preparing a laser protective liquid, which is simple and easy to implement, uses readily available raw materials, and is suitable for mass production.

[0012] Solution for solving the problem

[0013] [1] A light absorber, wherein the light absorber comprises an organofluorine-boron complex or a salt thereof; wherein the organofluorine-boron complex has the following structure:

[0014]

[0015] R1 is an electron-donating group;

[0016] R2, R5, R 10 Each can be independently represented by a H atom, sulfonic acid group, hydroxyl group, halogen atom, or C1-C6 alkyl group;

[0017] R3 and R8 each independently represent H atoms, sulfonic acid groups, hydroxyl groups, halogen atoms, or C1-C6 alkyl groups;

[0018] R4 and R9 each independently represent a H atom, a sulfonic acid group, a halogen atom, a hydroxyl group, an amino group, an N,N-dialkylamino group, a C1-C6 alkyl group, or a C1-C6 alkoxy group, wherein the alkyl group in the N,N-dialkylamino group is a C1-C6 alkyl group;

[0019] R6 and R7 represent H atoms, hydroxyl groups, or R6 and R7 linked together;

[0020] Z represents a linking bond or linking group.

[0021] [2] According to the light absorber described in [1] above, wherein R1 represents a C1-C6 alkylamino, amino, hydroxyl or C1-C6 alkoxy group;

[0022] R2, R5, R 10 Each can be represented independently by a H atom or a hydroxyl group;

[0023] R3 and R8 each independently represent a sulfonic acid group, a hydroxyl group, or a hydrogen atom;

[0024] R4 and R9 each independently represent an H atom, a sulfonic acid group, a hydroxyl group, an N,N-dialkylamino group, or a C1-C6 alkoxy group, wherein the alkyl group in the N,N-dialkylamino group is a C1-C6 alkyl group;

[0025] R6 and R7 represent H atoms, hydroxyl groups, or R6 and R7 linked together to form a carbonyl group;

[0026] Z represents a single bond or an ether group.

[0027] [3] The light absorber according to [1] or [2] above, wherein the light absorber has absorption peaks in the wavelength ranges of 500-600nm and 250-400nm.

[0028] [4] The light absorber according to any one of [1]-[3] above, wherein the organofluorine-boron complex is derived from an ultraviolet absorber, an aniline compound, and a fluorine-boron compound; wherein...

[0029] The ultraviolet absorber includes one of substituted or unsubstituted 2-hydroxybenzophenone or its salt, or substituted or unsubstituted phenyl salicylate or its salt;

[0030] The amino group at the para position of the aniline compound is replaced by an electron-donating group.

[0031] [5] A method for preparing a light absorber according to any one of [1]-[4] above, comprising mixing and reacting an ultraviolet absorber, an aniline compound and a fluorine-boron compound.

[0032] [6] According to the preparation method described in [5] above, the preparation method includes: in the presence of a catalyst, in an acidic solvent, using a complexing agent to carry out a complexation reaction of an ultraviolet absorber, an aniline compound and a fluorine-boron compound to obtain the product.

[0033] [7] A laser protective liquid, comprising a light absorber according to any one of [1]-[4] above;

[0034] Preferably, the laser protective liquid comprises a light absorber, a water-soluble resin, and a solvent; wherein, based on the total mass of the laser protective liquid being 100%,

[0035] The content of the light absorber is 0.1-0.5%, preferably 0.15-0.3%;

[0036] The content of the water-soluble resin is 4-10%, preferably 6-8%;

[0037] The solvent content is 89.5% to 95.9%, preferably 91.7% to 93.85%.

[0038] [8] According to the laser protective liquid described in [7] above, the weight average molecular weight of the water-soluble resin is 100,000 Da to 1,000,000 Da, preferably 400,000 Da to 800,000 Da; preferably, the water-soluble resin includes polymers such as polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyethylene oxide, methylcellulose, and ethylcellulose.

[0039] [9] The laser protective liquid according to [7] or [8] above, wherein the solvent includes organic solvent and inorganic solvent; based on the total mass of the laser protective liquid as 100%, the content of the organic solvent is 5-10%, preferably 7-9%; the content of the inorganic solvent is 79.5-90.9%, preferably 82.7-86.85%;

[0040] More preferably, the organic solvent includes one or more of phenyl acetate, diacetone alcohol, propylene glycol methyl ether, glycerol methyl ether, glycerol trimethyl ether, glycerol ethyl ether, dipropylene glycol methyl ether, and dipropylene glycol ethyl ether; the inorganic solvent includes water.

[0041]

[10] A method of using the laser protective liquid according to any one of [7]-[9] above, comprising the following steps: applying the laser protective liquid to the wafer surface twice, with different application speeds for the two applications.

[0042] The effects of the invention

[0043] 1. The light absorber of the present invention exhibits absorption peaks in both the visible and ultraviolet light regions. Furthermore, the light absorber of the present invention is water-soluble after salt formation, and can dissolve in water without the need for additional pH adjusters or complexing agents to aid dissolution, effectively preventing chip corrosion.

[0044] 2. The laser protective liquid of the present invention can be applied to the process of cutting wafers with ultraviolet laser and green laser in the semiconductor field, which solves the problem of having to change the matching protective liquid when changing the cutting laser and reduces the cost of process change.

[0045] 3. The preparation method of the laser protective liquid of the present invention is simple and easy to implement, the raw materials are easy to obtain, and it is suitable for mass production.

[0046] 4. When using the laser protective liquid of the present invention, a two-coating method can be adopted, which not only ensures the uniformity of the protective liquid film formation, but also reduces the amount of protective liquid used, thus saving costs. Attached Figure Description

[0047] Figure 1 The image shows a comparison of the surface of the aluminum electrode of the chip before and after immersion in the laser protective solution prepared in Example 4 for 7 days, observed under a microscope at 50x magnification. The left image is before 7 days, and the right image is after 7 days.

[0048] Figure 2 The image shows a comparison of the surface of the aluminum electrode of the chip before and after immersion in the laser protective solution prepared in Comparative Example 1 for 3 days, observed under a microscope at 50x magnification. The left image is before 3 days, and the right image is after 3 days.

[0049] Figure 3 The ultraviolet-visible absorption spectrum of the laser protective liquid of Example 4 of the present invention is shown.

[0050] Figure 4 The laser protective liquids of Example 4 and Comparative Example 1 are shown. The edges of the cut chips were observed under a metallographic microscope at 50x magnification after cutting using a green laser as the light source. Among them, (a) is Example 4 and (b) is Comparative Example 1. Detailed Implementation

[0051] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0052] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0053] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0054] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0055] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0056] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0057] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0058] <First Aspect>

[0059] A first aspect of the present invention provides a light absorber comprising an organofluorine-boron complex or a salt thereof; wherein the organofluorine-boron complex has the following structure:

[0060]

[0061] R1 is an electron-donating group;

[0062] R2, R5, R 10Each can be independently represented by a H atom, sulfonic acid group, hydroxyl group, halogen atom, or C1-C6 alkyl group;

[0063] R3 and R8 each independently represent H atoms, sulfonic acid groups, hydroxyl groups, halogen atoms, or C1-C6 alkyl groups;

[0064] R4 and R9 each independently represent an H atom, a sulfonic acid group, a halogen atom, a hydroxyl group, an amino group, an N,N-dialkylamino group, a C1-C6 alkyl group, or a C1-C6 alkoxy group, wherein the alkyl group in the N,N-dialkylamino group is a C1-C6 alkyl group;

[0065] R6 and R7 represent H atoms, hydroxyl groups, or R6 and R7 linked together;

[0066] Z represents a linking bond or linking group.

[0067] The light absorber of this invention exhibits absorption peaks in both the visible and ultraviolet regions. Furthermore, the organofluorine-boron complex of this invention is water-soluble after salt formation, dissolving in water without the need for additional pH adjusters or complexing agents, effectively preventing chip corrosion.

[0068] Furthermore, in some specific embodiments, R1 in this invention represents a C1-C6 alkylamino, amino, hydroxyl, or C1-C6 alkoxy group;

[0069] R2, R5, R 10 Each can be represented independently by an H atom or a hydroxyl group;

[0070] R3 and R8 each independently represent a sulfonic acid group, a hydroxyl group, or a hydrogen atom;

[0071] R4 and R9 each independently represent an H atom, a sulfonic acid group, a hydroxyl group, an N,N-dialkylamino group, or a C1-C6 alkoxy group, wherein the alkyl group in the N,N-dialkylamino group is a C1-C6 alkyl group;

[0072] R6 and R7 represent H atoms, hydroxyl groups, or R6 and R7 linked together to form a carbonyl group;

[0073] Z represents a single bond or an ether group.

[0074] Furthermore, in this invention, the light absorber exhibits absorption peaks in both the 500–600 nm and 250–400 nm wavelength ranges. Therefore, the light absorber of this invention exhibits absorption peaks in both the visible and ultraviolet regions.

[0075] In some specific implementations, the organofluorine-boron complex is derived from ultraviolet absorbers, aniline compounds, and fluorine-boron compounds.

[0076] In this invention, the ultraviolet absorber has an absorption peak in the ultraviolet region. Specifically, it can be a 2-hydroxybenzophenone compound with or without substituted groups, or a phenyl salicylate with or without substituted groups.

[0077] Specifically, the ultraviolet absorber may be one of the following compounds or salts: 2,2,4,4-tetrahydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 4-diethylaminoketo acid, 2,2-dihydroxy-4,4-dimethoxybenzophenone-5,5-disulfonic acid, and sodium 3,4-dihydroxy-9,10-dioxo-9,10-dihydroanthracene-2-sulfonate.

[0078] The amino group at the para position of the aniline compound is replaced by an electron-donating group, specifically p-methyl ether aniline.

[0079] <Second aspect>

[0080] A second aspect of the present invention provides a method for preparing a light absorber according to the first aspect, comprising mixing and reacting an ultraviolet absorber, an aniline compound, and a fluorine-boron compound.

[0081] Specifically, the preparation method includes: in the presence of a catalyst, in an acidic solvent, using a complexing agent to perform a complexation reaction of an ultraviolet absorber, an aniline compound, and a fluorine-boron compound to obtain the product.

[0082] In some preferred embodiments, the preparation method may include the following steps: in an acidic solvent, a UV absorber and an aniline compound undergo a preliminary reaction in the presence of a catalyst to obtain a preliminary reaction product;

[0083] The initial reaction product was complexed with a fluorine-boron compound in the presence of a complexing agent to obtain a light absorber containing an organofluorine-boron complex.

[0084] Specifically, in this invention, the acidic solvent can be propionic acid or acetic acid. When propionic acid is used as a solvent, it has a high boiling point, allowing for rapid heating and accelerating the reaction rate; while when acetic acid is used as a solvent, its low boiling point results in a low reaction temperature and a slow reaction rate. The complexing agent can be an ether, such as diethyl ether. The catalyst can be zinc powder and / or boric acid. The fluorinated boron compound is boron fluoride.

[0085] Furthermore, the present invention does not impose particular limitations on the reaction conditions, which are generally determined based on the extent of the overall reaction. Specifically, the preliminary reaction may be a reflux reaction at a temperature of 100-200°C to obtain preliminary reaction products; the complexation reaction may be carried out in the presence of an inert gas at a temperature of 90-120°C for 0.5-2 hours.

[0086] Furthermore, the present invention does not impose any particular limitation on the amount of each reactant used in the reaction process; the amount of each substance can be determined based on the chemical reaction formula.

[0087] Furthermore, the present invention does not impose any particular limitation on the amount of catalyst, acidic solvent and complexing agent used, and they can be used in appropriate amounts as needed.

[0088] Specifically, in this invention, the amount of catalyst used is generally 0.1-0.4g per 1g of UV absorber. The amount of acidic solvent used is generally 1-3mL per 1g of UV absorber. The amount of complexing agent used is generally 1-5mL per 1g of fluorine-boron compound.

[0089] <Third aspect>

[0090] A third aspect of the present invention provides a laser protective fluid comprising the light absorber described in the first aspect of the present invention. By applying the light absorber of the present invention to the laser protective fluid, the light absorber can be used simultaneously in semiconductor cutting processes using both ultraviolet and green lasers as light sources, avoiding the need to replace the laser protective fluid after changing the light source, reducing the time and economic costs of production process changes, and expanding the application range of the laser protective fluid.

[0091] In some specific embodiments, the laser protective liquid includes a light absorber, a water-soluble resin, and a solvent; wherein the total mass of the laser protective liquid is 100%.

[0092] The content of the light absorber is 0.1-0.5%, preferably 0.15-0.3%;

[0093] The content of the water-soluble resin is 4-10%, preferably 6-8%;

[0094] The content of the organic solvent is 89.5% to 95%, preferably 91.7% to 93.85%.

[0095] In this invention, based on the total mass of the laser protective liquid as 100%, the percentage content of the light absorber is 0.1-0.5%, preferably 0.15-0.3%. The inventors of this invention have discovered that when the percentage content of the light absorber is 0.1-0.5%, absorbance at both wavelengths can be simultaneously guaranteed. If the amount added is too low, the absorbance will not meet the usage requirements; if the amount added is too high, it will not only increase costs but also cause the protective film to absorb too much energy, resulting in melting or vaporization, thus failing to provide protection.

[0096] In this invention, the water-soluble resin can form a protective film layer to block and adhere debris generated during laser processing. In this invention, based on 100% of the total mass of the laser protective liquid, the content of the water-soluble resin is 4-10%, preferably 6-8%. The inventors of this invention have discovered that, according to different process requirements, the proportion of the water-soluble resin can be adjusted within this range to obtain protective liquids of different viscosities, adapting to different wafer morphologies.

[0097] In some specific embodiments, in this invention, the weight-average molecular weight of the water-soluble resin is 100,000 Da to 1,000,000 Da, preferably 400,000 Da to 800,000 Da. The inventors of this invention have discovered that when the weight-average molecular weight of the water-soluble resin is 100,000 Da to 1,000,000 Da, the protective solution exhibits excellent film-forming effect and can provide protection, thus not affecting absorbance and corrosion resistance. When the weight-average molecular weight of the water-soluble resin is too low, the film-forming effect of the protective solution is poor and cannot provide protection; when the weight-average molecular weight of the water-soluble resin is too high, the film is too thick, which is not conducive to cutting.

[0098] The present invention does not specifically limit the composition of the water-soluble resin, and it can be a water-soluble resin commonly used in the art. Specifically, the water-soluble resin includes one or more of the following polymers: polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyethylene oxide, methylcellulose, ethylcellulose, etc.

[0099] Furthermore, in this invention, the mass ratio of the light absorber to the water-soluble resin is 1:10 to 50, preferably 1:20 to 40. Since a higher resin mass fraction results in a thicker protective film, and consequently requires a higher absorbance, when the mass ratio of the light absorber to the water-soluble resin is 1:10 to 50, the protective film formed by the protective liquid will have appropriate absorbance. In this invention, the solvent content is 89.5% to 95.9%, preferably 91.7% to 93.85%. When the solvent content is 89.5% to 95.9%, the desired laser protective liquid can be prepared.

[0100] Specifically, in this invention, the solvent includes organic solvents and inorganic solvents; based on the total mass of the laser protective liquid as 100%, the content of the organic solvent is 5-10%, preferably 7-9%; when the content of the organic solvent is 5-10%, it can help adjust the viscosity of the protective liquid on the one hand, and help the protective liquid to form a film quickly during coating on the other hand.

[0101] The present invention does not specifically limit the organic solvent used; it may be any organic solvent commonly used in the art. Specifically, the organic solvent includes one or more of the following: phenyl acetate, diacetone alcohol, propylene glycol methyl ether, glycerol methyl ether, glycerol trimethyl ether, glycerol ethyl ether, dipropylene glycol methyl ether, and dipropylene glycol ethyl ether.

[0102] Furthermore, based on the total mass of the laser protective solution as 100%, the content of the inorganic solvent is 79.5-90.9%, preferably 82.7-86.85%. In this invention, the inorganic solvent is water, preferably ultrapure water, which can be deionized water with a resistivity greater than or equal to 18 MΩ.

[0103] <Fourth Aspect>

[0104] A fourth aspect of the present invention also provides a method for preparing a laser protective liquid according to a third aspect of the present invention, comprising the step of mixing the components of the laser protective liquid.

[0105] Specifically, the preparation method includes the following steps:

[0106] Step 1: Weigh each component according to its content in the laser protective solution;

[0107] Step 2: Add all components except the water-soluble resin to the container and stir until completely dissolved;

[0108] Step 3: Add water-soluble resin to the solution obtained in Step 2 and stir until it is uniform and transparent to obtain the laser protective solution.

[0109] Furthermore, the present invention also provides a method for using the laser protective liquid according to the present invention, comprising applying the laser protective liquid to the wafer surface twice, with the two application speeds being different. The present invention employs a two-application method for the laser protective liquid, which ensures the uniformity of the laser protective liquid film formation and reduces the amount of protective liquid used.

[0110] Specifically, the speed for the first coating can be 700–900 rpm, and the coating time is generally 10–20 seconds. For the second coating, different speed gradients can be used. Specifically, the coating can be performed first at a speed below 100 rpm for 25–45 seconds, then at a speed of 500–1500 rpm for 5–15 seconds, and finally at a speed of 2000–3000 rpm for 60–80 seconds. The amount of coating is not particularly limited in this invention; generally, 15–25 mL can be used for both the first and second coatings.

[0111] After applying the laser protective solution according to the above steps, laser cutting can be performed. After chip cutting is completed, deionized water can be used to clean away any residue, stains, and the laser protective solution film.

[0112] The laser cutting protective fluid of this invention has very good application prospects and potential for large-scale industrial application in the semiconductor field.

[0113] Example

[0114] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0115] Example 1

[0116] The light absorber is prepared by refluxing 20 mL of propionic acid, 2 g of zinc powder, 3 g of boric acid, 15 g of sodium 2,2-dihydroxy-4,4-dimethoxybenzophenone-5,5-disulfonic acid, and 8 mL of p-methyl ether aniline at 160 °C; then mixing it with 10 g of boron fluoride and 20 mL of diethyl ether, and reacting at 105 °C for 1 hour under nitrogen protection.

[0117] Example 2

[0118] The light absorber is prepared by refluxing 20 mL of acetic acid, 2 g of zinc powder, 3 g of boric acid, 15 g of 2,2,4,4-tetrahydroxybenzophenone, and 8 mL of p-methyl ether aniline at 140 °C; then mixing it with 10 g of boron fluoride and 20 mL of diethyl ether and reacting at 105 °C for 1 hour under nitrogen protection.

[0119] Example 3

[0120] The light absorber is prepared by refluxing 20 mL of propionic acid, 2 g of zinc powder, 3 g of boric acid, 14 g of 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, and 8 mL of p-methyl ether aniline at 160 °C; then mixing it with 10 g of boron fluoride and 20 mL of diethyl ether and reacting at 105 °C for 1 h under nitrogen protection.

[0121] Example 4-17

[0122] Step 1: Weigh each component according to the content of each component shown in Table 1. Among them, the light absorber in Examples 4-15 is the light absorber in Example 1, the light absorber in Example 16 is the light absorber in Example 2, and the light absorber in Example 17 is the light absorber in Example 3.

[0123] Step 2: Add all components except the water-soluble resin to the container and stir until completely dissolved;

[0124] Step 3: Add water-soluble resin to the solution obtained in Step 2 and stir until it is uniform and transparent to obtain the laser protective solution.

[0125] Table 1

[0126]

[0127] Comparative Examples 1-4

[0128] Weigh out the components according to the contents shown in Table 2 below. The light absorbers in Comparative Examples 1 and 2 are the same as those in Example 1. The rest are prepared in the same way as in Examples 4-17 to obtain the laser protective liquid.

[0129] Table 2

[0130]

[0131] Performance testing

[0132] 1. Absorbance

[0133] The laser protective solution was diluted with ultrapure water to a mass fraction of 0.5%. Using ultrapure water as a reference solution, the absorbance of the diluted solution in the ultraviolet-visible region was measured using a UV-Vis spectrophotometer with the measurement wavelength set to 200nm-800nm. The results are shown in Table 3 below. Figure 3 The ultraviolet-visible absorption spectrum of the laser protective liquid of Example 4 of the present invention is shown.

[0134] 2. Aluminum electrode corrosion time

[0135] The immersion etching method was used to test the corrosiveness of different laser protective solutions to aluminum electrodes on a chip. The specific test method was as follows: a 4×4 mm chip (coated with an Al metal layer) was immersed in the laser protective solution at room temperature. Before immersion, a microscopic image of the aluminum electrode was recorded. After immersion for 1-15 days, the chip was removed, rinsed with ultrapure water, and dried with nitrogen. Microscopic images of the aluminum electrode were recorded and compared with the original chip. If corrosion was observed on the aluminum electrode, the immersion time was recorded to obtain the time at which corrosion occurred. The results are shown in Table 3 below.

[0136] in, Figure 1 The image shows a comparison of the surface of the aluminum electrode of the chip before and after immersion in the laser protective solution prepared in Example 4 for 7 days, observed under a microscope at 50x magnification. Figure 2 The image shows a comparison of the surface of the aluminum electrode of the chip before and after immersion in the laser protective solution prepared in Comparative Example 1 for 3 days, observed under a microscope at 50x magnification.

[0137] 3. pH value

[0138] The pH was measured using a pH meter, and the results are shown in Table 3 below.

[0139] Table 3

[0140]

[0141] As shown in Table 3, the laser protective solution prepared in Example 4 achieves optimal absorbance and aluminum electrode corrosion resistance at 355nm and 532nm. Examples 5-17 all maintain a certain absorbance and can delay the corrosion time of the aluminum electrode by more than one week. Comparative Example 1, due to insufficient light absorber, failed to meet the required absorbance. Comparative Example 2, due to the use of polyvinylpyrrolidone with too low a molecular weight, resulted in poor film formation of the protective solution, failing to provide protection and causing a decrease in absorbance and corrosion resistance. Comparative Examples 3 and 4, due to changes in the light absorber, could not simultaneously guarantee absorbance at both wavelengths, thus losing their universal function. Furthermore, the excessively acidic nature of the light absorber from the single-absorption light source led to a low pH in the protective solution, increasing its corrosiveness to the aluminum electrode.

[0142] 4. Laser cutting experiment

[0143] In the laser protective solutions of Example 4 and Comparative Example 1, the chips were cut using a green laser as the light source. The cut chips were then observed under a 50x metallographic microscope, and the results are as follows: Figure 4 As shown.

[0144] Depend on Figure 4 As can be seen, after cutting in the laser protective solution of this invention, the chip edges are smooth, the cut edges are neat, and the cutting effect is excellent. However, after cutting in the laser protective solution of Comparative Example 1, the chip edges are rough and have burrs.

[0145] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0146] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A light absorber, characterized in that, The light absorber comprises an organofluorine-boron complex or a salt thereof; wherein the organofluorine-boron complex has the following structure: R1 represents a methoxy group; R2, R5, R 10 Each can be independently represented by a H atom, a sulfonic acid group, or a hydroxyl group; R3 and R8 each independently represent a H atom, a sulfonic acid group, or a hydroxyl group; R4 and R9 each independently represent an H atom, a sulfonic acid group, a hydroxyl group, or a C1~C6 alkoxy group; R6 and R7 represent H atoms or hydroxyl groups; Z represents the connection key.

2. The light absorber according to claim 1, characterized in that, R2, R5, R 10 Each can be represented independently by a H atom or a hydroxyl group; Z represents a single bond.

3. The light absorber according to claim 1 or 2, characterized in that, The light absorber exhibits absorption peaks in both the 500-600 nm and 250-400 nm wavelength ranges.

4. The light absorber according to claim 1, characterized in that, The organofluorine-boron complex was prepared from an ultraviolet absorber, aniline compounds, and fluorine-boron compounds; wherein... The ultraviolet absorber includes one of 2,2,4,4-tetrahydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, and 2,2-dihydroxy-4,4-dimethoxybenzophenone-5,5-disulfonic acid. The aniline compound is p-methyl ether aniline; The fluorinated boron compound is boron fluoride.

5. A method for preparing the organofluorine-boron complex according to claim 1, characterized in that, This includes mixing and reacting ultraviolet absorbers, aniline compounds, and fluorine-boron compounds; The ultraviolet absorber includes one of 2,2,4,4-tetrahydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, and 2,2-dihydroxy-4,4-dimethoxybenzophenone-5,5-disulfonic acid. The aniline compound is p-methyl ether aniline; The fluorinated boron compound is boron fluoride.

6. The preparation method according to claim 5, characterized in that, The preparation method includes: in the presence of a catalyst, in an acidic solvent, using a complexing agent to perform a complexation reaction of an ultraviolet absorber, an aniline compound, and a fluorine-boron compound to obtain the product.

7. A laser protective liquid, characterized in that, Includes the light absorber according to any one of claims 1-4.

8. The laser protective liquid according to claim 7, characterized in that, The laser protective liquid comprises a light absorber, a water-soluble resin, and a solvent; wherein, based on the total mass of the laser protective liquid being 100%, The content of the light absorber is 0.1~0.5%; The content of the water-soluble resin is 4-10%; The solvent content is 89.5% to 95.9%.

9. The laser protective liquid according to claim 8, characterized in that, Based on the total mass of the laser protective fluid being 100%, The content of the light absorber is 0.15~0.3%; The content of the water-soluble resin is 6-8%; The solvent content is 91.7~93.85%.

10. The laser protective liquid according to claim 8 or 9, characterized in that, The weight-average molecular weight of the water-soluble resin is 100,000 Da to 1,000,000 Da.

11. The laser protective liquid according to claim 10, characterized in that, The weight-average molecular weight of the water-soluble resin is 400,000 Da to 800,000 Da.

12. The laser protective liquid according to claim 10, characterized in that, The water-soluble resin includes polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyethylene oxide, methylcellulose, or ethylcellulose.

13. The laser protective liquid according to claim 8 or 9, characterized in that, The solvent includes organic solvents and inorganic solvents; based on the total mass of the laser protective liquid as 100%, the content of the organic solvent is 5-10%; and the content of the inorganic solvent is 79.5-90.9%.

14. The laser protective liquid according to claim 13, characterized in that, The solvent includes organic solvents and inorganic solvents; based on the total mass of the laser protective liquid as 100%, the content of the organic solvent is 7-9%; and the content of the inorganic solvent is 82.7-86.85%.

15. The laser protective liquid according to claim 13, characterized in that, The organic solvent includes one or more of phenyl acetate, diacetone alcohol, propylene glycol methyl ether, glycerol methyl ether, glycerol trimethyl ether, glycerol ethyl ether, dipropylene glycol methyl ether, and dipropylene glycol ethyl ether; the inorganic solvent includes water.

16. A method of using the laser protective liquid according to any one of claims 7-15, characterized in that, The process includes the following steps: applying the laser protective solution to the wafer surface in two separate applications at different speeds.

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