Plasma cutting protection liquid as well as preparation method and application thereof
By mixing ionic and non-ionic resins, plasma cutting protection liquid prepared by adding additives and moisturizers, the charging effect in plasma cutting is solved, and a high conductivity and stable cutting effect is achieved, ensuring the accuracy and structural integrity of wafer cutting.
Patent Information
- Application Number
- CN202510705119.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-29
- Publication Date
- 2025-08-12
AI Technical Summary
The existing plasma cutting protection liquid is prone to charging effects during wafer cutting, resulting in unstable etching morphology, especially when etching small structures, which affects the cutting accuracy and wafer structure integrity.
The ionic resin and the nonionic resin are mixed into the water-soluble resin body, and a high-conductive plasma cutting protection liquid is prepared by adding additives and moisturizers to improve the conductivity and film formation of the film layer and avoid charging effects.
It effectively avoids the charging effect, improves the conductivity and dielectric constant of the film layer, reduces the etching width offset, and ensures the cutting accuracy and the integrity of the wafer structure.
Smart Images
Figure CN120464265A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of semiconductor manufacturing technology, and in particular relates to a plasma cutting protection liquid and a preparation method and application thereof. Background Art
[0002] Plasma cutting is an emerging method of fine wafer cutting in recent years. Its main advantages over blade wheel cutting and laser cutting are as follows: First, it can achieve fine cutting of narrow cutting streets, improve wafer utilization, and improve the cutting yield of tiny wafers; second, it can avoid structural damage such as interlayer deformation and separation of fine structures around the cutting streets during the cutting process, and is suitable for cutting ultra-thin, fragile and structurally complex wafers; third, it can achieve diversified and complex graphic cutting. When using photoresist as a protective mask, graphic cutting of the corresponding shape of the cutting street can be achieved through photolithography.
[0003] In comparison, photoresist is more expensive and has a complex cleaning process. When there is no specific shape requirement for the cutting path, using photoresist as a protective material will consume higher costs. Therefore, for the first two application scenarios, dedicated plasma cutting protective fluid is a better choice.
[0004] Plasma cutting protective fluid is a functional chemical used in the wafer cutting process in the semiconductor field. Its function is to protect the wafer during the plasma cutting process. First, it prevents the flying debris or high-temperature thermal diffusion caused by laser grooving from affecting the functional area, thereby causing the integrated circuit to fail; second, it prevents the plasma from etching the wafer surface during the plasma cutting process and damaging the wafer surface structure; finally, after the cutting is completed, the film layer is removed from the wafer surface.
[0005] Charging is a common problem in plasma etching and plasma cutting. This effect is caused by the insulating properties of the etch mask. When electrons in the plasma cannot escape quickly, they accumulate on the mask surface, forming a localized electric field. This interferes with the path of the incident particles and affects the anisotropy of the etch, which is particularly pronounced when etching fine structures. Plasma cutting relies on high-aspect-ratio etching to separate silicon wafers. Therefore, if this effect occurs, it can cause a significant offset in the etch width, potentially affecting the wafer structure.
[0006] Common photoresist and plasma cutting protective fluid are usually resin solutions. After the resin forms a protective film on the wafer surface, the dielectric constant of the protective film is often less than 8, and the lower conductivity is the key influencing factor leading to the formation of the charging effect. Summary of the Invention
[0007] The technical problem solved by the present invention is to overcome the charging effect in plasma cutting, improve the conductivity of the cutting protection liquid and the conductivity of the film, and avoid the etching morphology problem caused by the charging effect.
[0008] In response to the technical problems existing in the prior art, the present invention has designed a plasma cutting protective fluid, its preparation method, and its application. The present invention proposes to use a mixture of ionic and non-ionic resins as the main water-soluble resin, and to formulate a highly conductive plasma cutting protective fluid that avoids the charging effect by adding additives and humectants.
[0009] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "consisting of..." etc. and similar meanings.
[0010] In order to solve the above-mentioned technical problems, the present invention adopts the following solutions: A plasma cutting protection liquid, calculated by weight, includes the following components: 10-30 parts of ionic resin; 3-10 parts of nonionic resin; 2-5 parts of additives; 5-10 parts of moisturizer; 50-75 parts water; Wherein, the ionic resin is a polymer having a sulfonic acid group or a carboxyl group; and the nonionic resin is a water-soluble polymer having a hydrophilic group.
[0011] Furthermore, the ionic resin is one or more of sodium polystyrene sulfonate, sulfonated phenolic resin, and polyamic acid.
[0012] Furthermore, the nonionic resin is one or more of polyethylene oxide, polyvinyl pyrrolidone, polyvinyl pyrrolidone-vinyl acetate, polyvinyl alcohol, polymethyl vinyl ether, and poly(2-ethyl-2-oxazoline).
[0013] Furthermore, the additive is a highly conjugated organic compound having a sulfonate group.
[0014] Furthermore, the additive is one or more of sodium 2-phenylindole-5-sulfonate, sodium diphenylamine sulfonate, 8-anilino-1-naphthalenesulfonic acid ammonium, and sodium quinoline-8-sulfonic acid.
[0015] Furthermore, the moisturizing agent is a water-soluble polyol.
[0016] Furthermore, the moisturizing agent is one or more of 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, triethylene glycol, sorbitol, xylitol, mannitol, neopentyl glycol, and hexylene glycol.
[0017] The present invention also discloses a method for preparing the plasma cutting protection liquid, which is characterized by comprising the following steps: Step 1: Weigh each component in its respective amount; Step 2: Add water and moisturizer into a container, seal and stir for at least 30 minutes until mixed evenly to obtain solution A; Step 3: Add the additive to solution A and stir for at least 30 minutes until it is completely dissolved to obtain solution B; Step 4: Add non-ionic resin to solution B and stir for at least 2 hours until it is uniform and transparent. Then add ionic resin and continue mixing and stirring for at least 2 hours until it is uniform and transparent. Filter the mixed solution and let it stand to obtain the plasma cutting protective solution.
[0018] The present invention also discloses a method for using the plasma cutting protective fluid, comprising the following steps: The plasma cutting protective liquid is spin-coated on the wafer surface to form a uniform plasma cutting protective film, followed by laser grooving and plasma cutting. After the wafer cutting is completed, deionized water is used to dissolve and clean the remaining residues and stains together with the plasma cutting protective film.
[0019] The invention also discloses a use of the plasma cutting protection liquid in plasma cutting wafers.
[0020] In the present invention, in order to further improve the performance of the plasma cutting protection fluid, its components can be optimized: 16-25 parts of ionic resin; 4-8 parts of non-ionic resin; 2-4 parts of additives; 6-9 parts of moisturizing agent; and 53-72 parts of water.
[0021] In the present invention, the molecular weight of the ionic resin is 10,000-80,000; the molecular weight of the nonionic resin is 10,000-20,000.
[0022] In the present invention, the ionic resin is preferably sodium polystyrene sulfonate.
[0023] In the present invention, the nonionic resin is preferably one of polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl pyrrolidone-vinyl acetate, and poly(2-ethyl-2-oxazoline).
[0024] In the present invention, the nonionic resin is more preferably polyvinyl pyrrolidone-vinyl acetate.
[0025] In the present invention, the additive is preferably 8-anilino-1-naphthalenesulfonic acid ammonium.
[0026] In the present invention, the moisturizing agent is preferably one or more of 1,3-butylene glycol, 1,4-butylene glycol, diethylene glycol, triethylene glycol, sorbitol, xylitol, and mannitol.
[0027] In the present invention, the moisturizing agent is more preferably triethylene glycol.
[0028] In the present invention, the water used is deionized water with a resistance of at least 18 MΩ.
[0029] In the use method of the present invention, the plasma cutting protection liquid used is an original liquid and does not need to be diluted.
[0030] In the present invention, the choice of resin is of great significance:
[0031] The selected ionic resin has a rigid structure and provides sufficient etching resistance. At the same time, it has good solubility in water, which can ensure that the film layer can be washed with water after etching.
[0032] The selected non-ionic resin has high water solubility and good compatibility. It also has excellent film-forming properties and can ensure the continuity and adhesion of the film layer.
[0033] In the system of the present invention, due to the requirement for etching resistance of the film layer formed by the plasma cutting protection liquid, it is necessary to ensure sufficient film thickness while controlling the viscosity of the protection liquid to be not too high, so certain restrictions need to be placed on the molecular weight of the resin.
[0034] Due to the rigid structure of ionic resin, too low molecular weight will cause the protective liquid to be unable to form a film, and too high molecular weight will affect the viscosity of the protective liquid; the main function of non-ionic resin is to assist in film formation, low molecular weight cannot play a film-forming role, and too high molecular weight will lead to poor compatibility between the two resins and poor uniformity of the film layer after coating.
[0035] In the present invention, the selected additive can increase the conductivity of the film layer and provide absorbance in the ultraviolet region, reducing thermal effects. The highly conjugated structure of the additive provides light absorption for the protective solution, and the sulfonate group increases both the water solubility of the additive and the conductivity of the protective solution, thereby increasing the conductivity of the film layer.
[0036] The present invention provides a plasma cutting protection liquid and its preparation method and application, which have the following beneficial effects: 1. The present invention adopts a mixture of ionic resin and non-ionic resin to form a water-soluble resin, and introduces additives and moisturizing agents to obtain a high-conductivity plasma cutting protective liquid that can avoid the charging effect.
[0037] 2. The additives used in the present invention can increase the conductivity of the film layer, improve the dielectric constant, effectively avoid the charging effect, and provide absorbance in the ultraviolet region to reduce the thermal impact of laser grooving.
[0038] 3. The present invention uses a moisturizing agent to increase the water content in the film layer, thereby ensuring the fluidity of the film layer and improving the conductivity of the film layer. BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Figure 1 : Figure 1 (a) and Figure 1 (b) Electron microscope images of film sections after coating with the plasma cutting protection liquid prepared in Example 1 and Comparative Example 1 at 10,000 times magnification; Figure 2 : Figure 2 (a) and Figure 2 (b) Images of adhesion test of the plasma cutting protection liquid prepared in Example 1 and Comparative Example 1 on the surface of a bare silicon wafer using the cross-grid method; Figure 3 : Figure 3 (a) and Figure 3 (b) Microscopic images of the side-cutting cut lines after laser grooving and plasma cutting using the plasma cutting protection liquid prepared in Example 1 and Comparative Example 1, magnified 500 times. DETAILED DESCRIPTION
[0040] The present invention will be further described below with reference to specific embodiments and accompanying drawings: Table 1 Components and ratios of Examples 1-9
[0041] Table 2 Components and ratios of Comparative Examples 1-6
[0042] The preparation method of the plasma cutting protection liquid of the present invention comprises the following steps: Step 1: Weigh each component in its respective amount; Step 2: Add water and moisturizer into a container, seal and stir for 30 minutes until mixed evenly to obtain solution A; Step 3: Add the additive to solution A while stirring, and stir for 30 minutes until completely dissolved to obtain solution B; Step 4: Add the non-ionic resin to solution B while stirring, stir for 2 hours until it is uniform and transparent, then add the ionic resin and continue mixing and stirring for 2 hours until it is uniform and transparent, filter the mixed solution and let it stand to obtain the plasma cutting protection liquid.
[0043] The method of using plasma cutting protective fluid includes the following steps: Spin-coat the plasma cutting protective liquid on the wafer surface to form a uniform plasma cutting protective film, and then perform laser grooving and plasma cutting. After the wafer cutting is completed, use deionized water to dissolve and clean the remaining residues and stains together with the plasma cutting protective film.
[0044] About performance testing and description: The test method for performance 1 conductivity is: The plasma cutting protection liquid was prepared according to the preparation method in the examples and comparative examples of the present invention, and the temperature was kept constant at 25° C. in a water bath. The conductivity of the plasma cutting protection liquid was tested using a conductivity meter. The test results are shown in Table 3.
[0045] Performance 2 The test method for etching selectivity is: Spin-coat the plasma cutting protection liquid on the surface of the bare silicon wafer and record the previous value of the film thickness.
[0046] After grooving the wafer surface with a laser, the silicon substrate is etched to a depth of about 100-200μm using dry etching.
[0047] Record the film thickness at this time and calculate the difference before and after etching. The etching ratio is the ratio of the actual depth of the silicon substrate etched to the film difference. The test results are shown in Table 3 and Figure 3 .
[0048] Performance 3 Adhesion test method is: After applying plasma cutting protection liquid on the bare silicon wafer, bake it at 50℃ for 5 minutes to dry it into a film. Test the adhesion by the cross-grid method. The test results are shown in Figure 1 and Figure 2 .
[0049] Table 3 Test results
[0050] Analysis of the test results: It can be seen from Table 3 that the plasma cutting protection liquids of Examples 1-9 of the present invention have high conductivity, good electrical conductivity, and high etching selectivity.
[0051] Comparative Example 1 lacks additives, resulting in reduced conductivity and poor conductivity of the film layer; Comparative Example 2 did not use the ionic resin with a rigid structure, resulting in a low film etching selectivity; Comparative Example 3 did not use non-ionic resin, resulting in the protection liquid not forming a film; Comparative Example 4 uses a non-ionic additive, which results in poor stability of the protective liquid and inability to form a uniform transparent film layer; Comparative Example 5 uses inorganic salt instead of 8-anilino-1-naphthalenesulfonic acid ammonium to improve conductivity, resulting in a large thermal impact of laser grooving and a low etching selectivity; Comparative Example 6 uses (8-hydroxyquinoline)aluminum as an additive, but the solubility is poor and a uniform, stable and transparent solution cannot be obtained.
[0052] Further comparison is made through the accompanying drawings in the specification: Figure 1 middle, Figure 1 (a) and Figure 1 (b) Electron microscope images of film sections after coating with the plasma cutting protection liquid prepared in Example 1 and Comparative Example 1 at 10,000 times magnification; from Figure 1 (a) It can be seen that the film layer has good density. Figure 1 (b) It can be seen that the film layer has poor density.
[0053] Figure 2 middle, Figure 2 (a) and Figure 2 (b) Images of adhesion test of the plasma cutting protection liquid prepared in Example 1 and Comparative Example 1 on the surface of a bare silicon wafer using the cross-grid method; from Figure 2 (a) shows that the film has strong adhesion. Figure 2 In (b), it can be seen that the film adhesion is poor.
[0054] Figure 3 middle, Figure 3 (a) and Figure 3 (b) Microscopic images of the side-cutting cut lines after laser grooving and plasma cutting using the plasma cutting protection liquid prepared in Example 1 and Comparative Example 1, magnified 500 times.
[0055] from Figure 3 In (a), it can be seen that the etching morphology is good and the upper and lower etching widths are consistent; from Figure 3 In (b), it can be seen that the etching angle is shifted due to the obvious charging effect, and the bottom etching width is larger than the top etching width.
[0056] The present invention utilizes a mixed water-soluble resin, and by introducing additives and humectants, it produces a highly conductive plasma cutting protective fluid that avoids charging effects, enabling high-profile plasma cutting. Furthermore, the additives used in the present invention increase the conductivity of the film layer, improve the dielectric constant, effectively avoid charging effects, and provide absorbance in the ultraviolet region, reducing the thermal effects of laser slotting. Furthermore, the use of humectants in the present invention increases the water content of the film layer, ensuring its fluidity and improving its conductivity.
[0057] The present invention has been described above by way of example in conjunction with the embodiments and accompanying drawings. It is obvious that the implementation of the present invention is not limited to the above-mentioned methods. As long as various improvements are made using the method concepts and technical solutions of the present invention, or the concepts and technical solutions of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.
Claims
1. A plasma cutting protective liquid, characterized in that: Calculated by weight, it includes the following components: 10-30 parts of ionic resin; 3-10 parts of nonionic resin; 2-5 parts of additives; 5-10 parts of moisturizer; 50-75 parts water; Wherein, the ionic resin is a polymer having a sulfonic acid group or a carboxyl group; and the nonionic resin is a water-soluble polymer having a hydrophilic group.
2. The plasma cutting protection liquid according to claim 1, characterized in that: The ionic resin is one or more of sodium polystyrene sulfonate, sulfonated phenolic resin and polyamic acid.
3. The plasma cutting protection liquid according to claim 1, characterized in that: The nonionic resin is one or more of polyethylene oxide, polyvinyl pyrrolidone, polyvinyl pyrrolidone-vinyl acetate copolymer, polyvinyl alcohol, polymethyl vinyl ether, and poly (2-ethyl-2-oxazoline).
4. The plasma cutting protection liquid according to claim 1, characterized in that: The additive is a highly conjugated organic compound with a sulfonate group.
5. The plasma cutting protection liquid according to claim 1 or 4, characterized in that: The additive is one or more of sodium 2-phenylindole-5-sulfonate, sodium diphenylamine sulfonate, 8-anilino-1-naphthalenesulfonic acid ammonium, and sodium salt of quinoline-8-sulfonic acid.
6. The plasma cutting protection liquid according to claim 1, characterized in that: The moisturizing agent is a water-soluble polyol.
7. The plasma cutting protection liquid according to claim 1 or 6, characterized in that: The moisturizing agent is one or more of 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, triethylene glycol, sorbitol, xylitol, mannitol, neopentyl glycol, and hexylene glycol.
8. A method for preparing the plasma cutting protection liquid according to any one of claims 1 to 7, characterized in that The following steps are involved: Step 1: Weigh each component in its respective amount; Step 2: Add water and moisturizer into a container, seal and stir for at least 30 minutes until mixed evenly to obtain solution A; Step 3: Add the additive to solution A and stir for at least 30 minutes until it is completely dissolved to obtain solution B; Step 4: Add non-ionic resin to solution B and stir for at least 2 hours until it is uniform and transparent. Then add ionic resin and continue mixing and stirring for at least 2 hours until it is uniform and transparent. Then filter and let it stand to obtain the plasma cutting protection liquid.
9. A method for using the plasma cutting protection liquid according to any one of claims 1 to 7, characterized in that The following steps are involved: The plasma cutting protective liquid is spin-coated on the wafer surface to form a uniform plasma cutting protective film, followed by laser grooving and plasma cutting. After the wafer cutting is completed, deionized water is used to dissolve and clean the remaining residues and stains together with the plasma cutting protective film.
10. Use of the plasma cutting protection liquid according to any one of claims 1 to 7 in plasma cutting wafers.