Laser cutting protective fluid

Abstract

The invention discloses a laser cutting protection liquid, which belongs to the field of wafer cutting and comprises the following components by mass: 5%-10% of an AB-type block polymer surfactant, 40%-60% of a water-soluble polymer, 3%-6% of a moisturizer, 0.1%-0.2% of a corrosion inhibitor, 0.3%-0.6% of 2-hydroxy-4-n-octyloxybenzophenone, 0.5%-5% of 2,6-di-tert-butyl-p-cresol, 10%-15% of an organic detergent, and the balance is water. The laser cutting protection liquid can reduce yellowing of a cutting groove and reduce the precipitation of miscellaneous colors in the cutting groove; and has excellent heat dissipation, heat resistance and cooling capabilities, so that a chip is less affected by laser thermal radiation, and on the premise of ensuring a cutting depth, the width of the cutting groove can be made narrower, thereby reducing chip loss.

Description

Technical Field

[0001] The invention relates to a laser cutting protective liquid and belongs to the field of wafer cutting. Background Art

[0002] Semiconductor wafer cutting methods can be divided into laser cutting and grinding wheel cutting. Regardless of processing efficiency, yield, cost, etc., laser cutting is far superior to grinding wheel cutting, and laser cutting has become the mainstream choice of semiconductor manufacturers. During laser cutting, there are several laser points focused on the surface of the wafer, which vaporizes the material at the focus. If the heat dissipation is not timely, a large amount of heat energy will be generated on the surface of the wafer, affecting the area connected to the preset cutting seam. Overheating will reduce the wafer yield. At the same time, metal debris and cutting dust will be generated during the cutting process. To solve these problems, laser cutting protection fluid is used during laser cutting, which is beneficial to the heat dissipation of the wafer, isolating metal debris and cutting dust from falling directly on the surface of the wafer, thereby improving the cutting accuracy. However, the laser cutting protection fluid in the prior art is easy to cause the cutting groove to turn yellow after cutting the wafer, or leave a mixed color precipitation in the cutting groove, affecting the quality of the chip. Moreover, in order to meet the needs of subsequent splitting, the width of the cutting groove after cutting the wafer with the laser cutting protection fluid in the prior art is large, which increases the chip loss. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the present invention provides a laser cutting protective liquid, which reduces yellowing and miscellaneous precipitation of the cutting groove, and can make the cutting groove width narrower while meeting the subsequent splitting requirements.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A laser cutting protection liquid comprises the following components by mass: 5%-10% AB type block polymer surfactant, 40%-60% water-soluble polymer, 3%-6% moisturizer, 0.1%-0.2% corrosion inhibitor, 0.3%-0.6% 2-hydroxy-4-n-octyloxybenzophenone, 0.5%-5% 2,6-di-tert-butyl-p-cresol, 10%-15% organic detergent, and the balance is water.

[0006] The laser cutting protective liquid provided in the present application has excellent lubrication, heat dissipation, heat resistance and cooling effects. The chip is less radiated by laser heat, the cutting groove width after laser cutting is smaller, the chip loss is lower, and it can solve the problem of yellowing of the groove and colorful precipitation in the groove after laser cutting.

[0007] The AB type block polymer surfactant can reduce the surface tension of the laser cutting protection liquid. Furthermore, the AB type block polymer surfactant is a block copolymer of dimethylaminoethyl acrylate and methyl acrylate, which has the functions of wetting, anti-sticking, defoaming, solubilizing, dispersing, washing, anti-corrosion and antistatic.

[0008] Furthermore, the content of the AB type block polymer surfactant in the laser cutting protection liquid is 5%.

[0009] Furthermore, the water-soluble polymer is polyvinyl alcohol.

[0010] Furthermore, the content of the water-soluble polymer in the laser cutting protection liquid is 50%. The drag reduction effect can be achieved by significantly reducing the turbulent friction resistance. The charged parts of polyvinyl alcohol can neutralize the charge of the colloid particles, destroy the stability of the colloid particles in water and cause them to collide. The long polymer chain entangles many fine particles generated after laser cutting, plays a flocculation role, and forms a protective film on the wafer surface to block laser cutting heat, dust, and metal debris, which can better protect the wafer.

[0011] Furthermore, the moisturizing agent is polyethylene glycol, which has low volatility and can retain moisture. When it acts on the surface of the wafer, it promotes the gradual formation of a protective film on the surface of the wafer.

[0012] Furthermore, the corrosion inhibitor is polyethylene, which plays a role in preventing or slowing down material corrosion.

[0013] Furthermore, the organic cleaning agent is propylene glycol methyl ether, which is beneficial to the film-forming temperature of the laser cutting protection liquid and promotes the condensation of the laser cutting protection liquid into a film.

[0014] Furthermore, the content of the organic detergent in the laser cutting protection liquid is 12%, which can ensure that the coating has the characteristics of a good state and better prevent cutting dust and metal debris from covering the wafer surface.

[0015] Further, the content of the 2-hydroxy-4-n-octyloxybenzophenone in the laser cutting protection liquid is 0.5%, and the content of the 2,6-di-tert-butyl-p-cresol in the laser cutting protection liquid is 0.5%.

[0016] The beneficial effects of the present invention are: the laser cutting protective liquid of the present invention can reduce the yellowing of the cutting groove and reduce the precipitation of miscellaneous colors in the cutting groove. Moreover, the laser cutting protective liquid has excellent heat dissipation capacity, so that the chip is less affected by laser thermal radiation. Under the premise of ensuring the cutting depth, the width of the cutting groove can be made narrower, thereby reducing chip loss.

[0017] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or may be understood through implementation of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a physical picture of a part of an uncut LED wafer under a microscope.

[0019] Figure 2 This is a real picture of the cut marks obtained by cutting after forming a film of the laser cutting protection liquid of Example 1 on a wafer.

[0020] Figure 3 This is a real picture of the cut marks obtained after a certain laser cutting protective liquid on the market is formed into a film on the wafer.

[0021] Figure 4 This is a real picture of the cut marks obtained by cutting after forming a film on the wafer using another type of laser cutting protection liquid on the market. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be understood that, under the premise of no conflict, any and all embodiments of the present invention can be combined with the technical features in any other embodiment or multiple other embodiments to obtain another embodiment. The present invention includes such a combination to obtain another embodiment.

[0024] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter belongs. If there are multiple definitions for a term, the definition herein shall prevail.

[0025] When cutting a wafer into chips, laser cutting is usually performed first, cutting to a depth of 50μm±5μm, but it is not completely cut with laser. Laser cutting only forms cutting grooves, which are then completely disconnected by cleaving, making the fracture smoother.

[0026] The principle of laser cutting is to focus the laser on the wafer, so that the wafer is quickly heated to vaporization, and evaporates to form holes. The laser cutting protection liquid has a great influence on the cutting width. After the laser cutting protection liquid forms a film on the surface of the wafer, it can isolate metal debris and cutting dust from falling directly on the surface of the wafer to protect the wafer. However, the stronger the protection ability is, the better. When the protection is too strong, the necessary time for laser cutting to the required depth of splitting is longer, and the area of ​​the wafer heated is larger, resulting in a larger cutting width. In addition, the laser cutting protection liquid in the prior art is also prone to yellowing the cutting groove after cutting the wafer, or leaving a mixed color precipitate in the cutting groove.

[0027] In response to the above problems, an embodiment of the present application provides a laser cutting protection liquid, which includes the following components by mass: 5%-10% AB-type block polymer surfactant, 40%-60% water-soluble polymer, 3%-6% moisturizer, 0.1%-0.2% corrosion inhibitor, 0.3%-0.6% 2-hydroxy-4-n-octyloxybenzophenone, 0.5%-5% 2,6-di-tert-butyl-p-cresol, 10%-15% organic detergent, and the balance is water.

[0028] The laser cutting protective liquid provided in the present application has excellent lubrication, heat dissipation, heat resistance and cooling effects. The chip is less radiated by laser heat, the cutting groove width after laser cutting is smaller, the chip loss is lower, and it can solve the problem of yellowing of the groove and colorful precipitation in the groove after laser cutting.

[0029] The preparation method of the laser cutting protective liquid of the embodiment of the present application is as follows: add each raw material into the mixer in turn, first stir at a speed of 500r / min for 40min, then stir at a speed of 1000r / min for 25min, and finally stir at a speed of 1500r / min for 5min to obtain the laser cutting protective liquid.

[0030] Example 1

[0031] Weigh 50 parts of polyvinyl alcohol (water-soluble polymer), 0.5 parts of 2-hydroxy-4-n-octyloxybenzophenone, 0.5 parts of 2,6-di-tert-butyl-p-cresol, 12 parts of propylene glycol methyl ether (organic detergent), 5 parts of AB type block polymer (surfactant), 0.1 parts of polyethylene, 5 parts of polyvinyl alcohol, and 26.9 parts of pure water for use.

[0032] In a dust-free environment, the raw materials were added into a mixer in sequence at room temperature, and the rotation speed and time were set to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protection liquid of Example 1.

[0033] The laser protection liquid prepared above is evenly applied to the surface of the wafer. After film formation, it is put into a laser cutting machine with a power of 15w and a wavelength of 355nm for cutting. After cutting, it is put into a two-fluid cleaning machine for cleaning, nitrogen blowing, and spin drying.

[0034] Comparative Example 2

[0035] Weigh 70 parts of polyvinyl alcohol (water-soluble polymer), 0.5 parts of 2-hydroxy-4-n-octyloxybenzophenone, 0.5 parts of 2,6-di-tert-butyl-p-cresol, 12 parts of propylene glycol methyl ether (organic detergent), 5 parts of AB type block polymer (surfactant), 5 parts of polyethylene glycol (moisturizer), 0.1 parts of polyethylene (corrosion inhibitor), and 6.9 parts of pure water for use.

[0036] In a dust-free environment, add the raw materials into the mixer in turn at room temperature, set the speed and time to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protective liquid of Comparative Example 2.

[0037] The laser protection liquid prepared above is evenly applied to the surface of the wafer.

[0038] Comparative Example 3

[0039] Weigh 20 parts of polyvinyl alcohol (water-soluble polymer), 0.5 parts of 2-hydroxy-4-n-octyloxybenzophenone, 0.5 parts of 2,6-di-tert-butyl-p-cresol, 12 parts of propylene glycol methyl ether (organic detergent), 5 parts of AB type block polymer (surfactant), 5 parts of polyethylene glycol (moisturizer), 0.1 parts of polyethylene (corrosion inhibitor), and 56.9 parts of pure water for use.

[0040] In a dust-free environment, add the raw materials into the mixer in turn at room temperature, set the speed and time to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protective liquid of Comparative Example 3.

[0041] The laser protection liquid prepared above is evenly applied to the surface of the wafer.

[0042] The ingredients and film-forming effects of Example 1, Comparative Example 2 and Comparative Example 3 are shown in Table 1.

[0043] Table 1

[0044] Example 1 Comparative Example 2 Comparative Example 3 Polyvinyl alcohol 50 70 20 2-Hydroxy-4-octyloxybenzophenone 0.5 0.5 0.5 2,6-Di-tert-butyl-p-cresol 0.5 0.5 0.5 Propylene glycol methyl ether 12 12 12 AB type block polymer 5 5 5 Polyethylene glycol 5 5 5 Polyethylene 0.1 0.1 0.1 Pure water 26.9 6.9 56.9 Film-forming effect Ideal film formation Uneven film thickness Unable to form film

[0045] The film formation of Example 1 is uniform, non-viscous, and moderate in speed. The film formation of Example 1 is ideal. Compared with Example 1, the polyvinyl alcohol in Comparative Example 3 is reduced from 50 parts to 20 parts, and the pure water is increased from 26.9 parts to 56.9 parts. When Comparative Example 3 is dripped onto the chip surface, the protective liquid is in a liquid state and a film cannot be formed. Compared with Example 1, the polyvinyl alcohol in Comparative Example 2 is increased from 50 parts to 70 parts, and the pure water is reduced from 26.9 parts to 6.9 parts. When Comparative Example 2 is just dripped onto the chip surface, the protective liquid has not yet completely covered the entire chip, and the protective liquid has solidified, resulting in uneven film thickness.

[0046] Comparative Example 4

[0047] Weigh 50 parts of polyvinyl alcohol (water-soluble polymer), 0.5 parts of 2-hydroxy-4-n-octyloxybenzophenone, 0.5 parts of 2,6-di-tert-butyl-p-cresol, 34 parts of propylene glycol methyl ether (organic detergent), 5 parts of AB block polymer (surfactant), 5 parts of polyethylene glycol (moisturizer), 0.1 parts of polyethylene (corrosion inhibitor), and 4.9 parts of pure water for use.

[0048] In a dust-free environment, add the raw materials into the mixer in turn at room temperature, set the speed and time to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protective liquid of Comparative Example 4.

[0049] The laser protection liquid prepared above is evenly applied to the surface of the wafer.

[0050] Comparative Example 5

[0051] Weigh 50 parts of polyvinyl alcohol (water-soluble polymer), 0.5 parts of 2-hydroxy-4-n-octyloxybenzophenone, 0.5 parts of 2,6-di-tert-butyl-p-cresol, 1 part of propylene glycol methyl ether (organic detergent), 5 parts of AB type block polymer (surfactant), 5 parts of polyethylene glycol (moisturizer), 0.1 parts of polyethylene (corrosion inhibitor), and 37.9 parts of pure water for use.

[0052] In a dust-free environment, add each raw material into a mixer in turn at room temperature, set the speed and time to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protective liquid of Comparative Example 5.

[0053] The laser protection liquid prepared above is evenly applied to the surface of the wafer.

[0054] The ingredients and film-forming time of Example 1, Comparative Example 4 and Comparative Example 5 are shown in Table 2.

[0055] Table 2

[0056] Example 1 Comparative Example 4 Comparative Example 5 Polyvinyl alcohol 50 50 50 2-Hydroxy-4-octyloxybenzophenone 0.5 0.5 0.5 2,6-Di-tert-butyl-p-cresol 0.5 0.5 0.5 Propylene glycol methyl ether 12 34 1 AB type block polymer 5 5 5 Polyethylene glycol 5 5 5 Polyethylene 0.1 0.1 0.1 Pure water 26.9 4.9 37.9 Film forming time 15s 5s 60s

[0057] The film-forming time of Example 1 is moderate. In Comparative Example 5, compared with Example 1, propylene glycol methyl ether is reduced from 12 parts to 1 part, pure water is increased from 26.9 parts to 37.9 parts, and the film-forming time is increased from 15s to 60s, which will reduce the cutting efficiency. The film-forming time of Comparative Example 5 is too long. In Comparative Example 4, compared with Example 1, propylene glycol methyl ether is increased from 12 parts to 34 parts, pure water is reduced from 26.9 parts to 4.9 parts, and the film-forming time is reduced from 15s to 5s. It takes at least 10s to complete the uniform coating, and some areas have solidified into films. The film-forming time of Comparative Example 4 is too short.

[0058] Example 6

[0059] Weigh 50 parts of polyvinyl alcohol (water-soluble polymer), 0.5 parts of 2-hydroxy-4-n-octyloxybenzophenone, 0.5 parts of 2,6-di-tert-butyl-p-cresol, 34 parts of propylene glycol methyl ether (organic detergent), 10 parts of AB type block polymer (surfactant), 5 parts of polyethylene glycol (moisturizer), 0.1 parts of polyethylene (corrosion inhibitor), and 21.9 parts of pure water for use.

[0060] In a dust-free environment, each raw material was added into a mixer in turn at room temperature, and the speed and time were set to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protection liquid of Example 6.

[0061] The laser protection liquid prepared above is evenly applied to the surface of the wafer.

[0062] Comparative Example 7

[0063] Weigh 50 parts of polyvinyl alcohol (water-soluble polymer), 0.5 parts of 2-hydroxy-4-n-octyloxybenzophenone, 0.5 parts of 2,6-di-tert-butyl-p-cresol, 1 part of propylene glycol methyl ether (organic detergent), 1 part of AB type block polymer (surfactant), 5 parts of polyethylene glycol (moisturizer), 0.1 parts of polyethylene (corrosion inhibitor), and 30.9 parts of pure water for use.

[0064] In a dust-free environment, add the raw materials into the mixer in turn at room temperature, set the speed and time to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protective liquid of Comparative Example 7.

[0065] The laser protection liquid prepared above is evenly applied to the surface of the wafer.

[0066] The ingredients and defoaming effects of Example 1, Example 6 and Comparative Example 7 are shown in Table 3.

[0067] Table 3

[0068] Example 1 Example 6 Comparative Example 7 Polyvinyl alcohol 50 50 50 2-Hydroxy-4-octyloxybenzophenone 0.5 0.5 0.5 2,6-Di-tert-butyl-p-cresol 0.5 0.5 0.5 Propylene glycol methyl ether 12 34 1 AB type block polymer 5 10 1 Polyethylene glycol 5 5 5 Polyethylene 0.1 0.1 0.1 Pure water 26.9 21.9 30.9 Defoaming effect No foam No foam Lots of foam

[0069] There was no foam in the preparation and dripping process of Example 1. Compared with Example 1, the AB-type block polymer surfactant was increased from 5 parts to 10 parts, and the pure water was decreased from 26.9 parts to 21.9 parts in Example 6. There was no foam in the preparation and dripping process of Example 6, and the defoaming effect was basically the same as that of Example 1. It can be seen that the defoaming effect of Example 1 is already ideal, and there is no need to increase the content of AB-type block polymer, which is beneficial to reduce the cost of cutting protection liquid. Compared with Example 1, the AB-type block polymer surfactant was decreased from 5 parts to 1 part, and the pure water was increased from 26.9 parts to 30.9 parts in Comparative Example 7. A large amount of foam appeared in the preparation process of Comparative Example 7, and the foam could not be completely removed after standing for a long time.

[0070] Comparative Example 8

[0071] Weigh 50 parts of polyvinyl alcohol (water-soluble polymer), 0.05 parts of 2-hydroxy-4-n-octyloxybenzophenone, 0.5 parts of 2,6-di-tert-butyl-p-cresol, 12 parts of propylene glycol methyl ether (organic detergent), 5 parts of AB block polymer (surfactant), 5 parts of polyethylene glycol (moisturizer), 0.1 parts of polyethylene (corrosion inhibitor), and 27.35 parts of pure water for use.

[0072] In a dust-free environment, add each raw material into a mixer in turn at room temperature, set the rotation speed and time to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protective liquid of Comparative Example 8.

[0073] The laser protection liquid prepared above is evenly applied to the surface of the wafer. After film formation, it is put into a laser cutting machine with a power of 15w and a wavelength of 355nm for cutting. After cutting, it is put into a two-fluid cleaning machine for cleaning, nitrogen blowing, and spin drying.

[0074] Comparative Example 9

[0075] Weigh 50 parts of polyvinyl alcohol (water-soluble polymer), 5 parts of 2-hydroxy-4-n-octyloxybenzophenone, 0.05 parts of 2,6-di-tert-butyl-p-cresol, 12 parts of propylene glycol methyl ether (organic detergent), 5 parts of AB type block polymer (surfactant), 5 parts of polyethylene glycol (moisturizer), 0.1 parts of polyethylene (corrosion inhibitor), and 22.4 parts of pure water for use.

[0076] In a dust-free environment, add the raw materials into the mixer in turn at room temperature, set the speed and time to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protective liquid of Comparative Example 9.

[0077] The laser protection liquid prepared above is evenly applied to the surface of the wafer. After film formation, it is put into a laser cutting machine with a power of 15w and a wavelength of 355nm for cutting. After cutting, it is put into a two-fluid cleaning machine for cleaning, nitrogen blowing, and spin drying.

[0078] Comparative Example 10

[0079] Weigh 50 parts of polyvinyl alcohol (water-soluble polymer), 0.5 parts of 2-hydroxy-4-n-octyloxybenzophenone, 0.05 parts of 2,6-di-tert-butyl-p-cresol, 12 parts of propylene glycol methyl ether (organic detergent), 5 parts of AB block polymer (surfactant), 5 parts of polyethylene glycol (moisturizer), 0.1 parts of polyethylene (corrosion inhibitor), and 27.35 parts of pure water for use.

[0080] In a dust-free environment, add the raw materials into the mixer in turn at room temperature, set the speed and time to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protective liquid of Comparative Example 10.

[0081] The laser protection liquid prepared above is evenly applied to the surface of the wafer. After film formation, it is put into a laser cutting machine with a power of 15w and a wavelength of 355nm for cutting. After cutting, it is put into a two-fluid cleaning machine for cleaning, nitrogen blowing, and spin drying.

[0082] Embodiment 11

[0083] Weigh 50 parts of polyvinyl alcohol (water-soluble polymer), 0.5 parts of 2-hydroxy-4-n-octyloxybenzophenone, 5 parts of 2,6-di-tert-butyl-p-cresol, 12 parts of propylene glycol methyl ether (organic detergent), 5 parts of AB type block polymer (surfactant), 5 parts of polyethylene glycol (moisturizer), 0.1 parts of polyethylene (corrosion inhibitor), and 22.4 parts of pure water for use.

[0084] In a dust-free environment, add the raw materials into the mixer in turn at room temperature, set the rotation speed and time to 500 r / min (40 min), 1000 r / min (25 min), and 1500 r / min (5 min), respectively, to obtain the laser cutting protective liquid of Example 11.

[0085] The laser protection liquid prepared above is evenly applied to the surface of the wafer. After film formation, it is put into a laser cutting machine with a power of 15w and a wavelength of 355nm for cutting. After cutting, it is put into a two-fluid cleaning machine for cleaning, nitrogen blowing, and spin drying.

[0086] The ingredients and cutting effects of Example 1, Comparative Example 8, Comparative Example 9, Comparative Example 10 and Example 11 are shown in Table 4.

[0087] Table 4

[0088] Example 1 Comparative Example 8 Comparative Example 9 Comparative Example 10 Embodiment 11 Polyvinyl alcohol 50 50 50 50 50 2-Hydroxy-4-octyloxybenzophenone 0.5 0.05 5 0.5 0.5 2,6-Di-tert-butyl-p-cresol 0.5 0.5 0.05 0.05 5 Propylene glycol methyl ether 12 12 12 12 12 AB type block polymer 5 5 5 5 5 Polyethylene glycol 5 5 5 5 5 Polyethylene 0.1 0.1 0.1 0.1 0.1 Pure water 26.9 27.35 22.4 27.35 22.4 Cutting width (um) 12 18 10 12 12 Cutting depth (um) 51 53 39 50 50 Groove color change none none none Yellowing none

[0089] In Example 1, while meeting the effect of a cutting depth of nearly 50um (a cutting width of 50um±5um can meet the subsequent splitting requirements), the cutting width is only 12um. Example 1 can reduce the laser cutting width, thereby reducing the chip yield loss. In Comparative Example 9, compared with Example 1, 2-hydroxy-4-octyloxybenzophenone is increased from 0.5 parts to 5 parts, and pure water is decreased from 26.9 parts to 22.4 parts. Although the cutting width of Comparative Example 9 is only 10um, due to severe energy absorption, the laser cutting depth is only 39um, which does not meet the subsequent splitting requirements. In Comparative Example 8, compared with Example 1, 2-hydroxy-4-octyloxybenzophenone is decreased from 0.5 parts to 0.05 parts, and pure water is increased from 26.9 parts to 27.35 parts. Although the cutting depth of Comparative Example 8 is 53um, the cutting width has reached 18um, and the chip is more exposed to laser heat radiation, resulting in more chip losses.

[0090] Although the spacing between chips on the same wafer is preset, with narrower cutting technology, the grooves reserved for cutting can be made smaller during front-end chip design, so that more chips can be placed on the same wafer area, which is conducive to improving chip production capacity.

[0091] After the wafer protected by Example 1 was laser cut by the chip, the cutting groove did not turn yellow and the cut marks were relatively neat. Compared with Example 1, Example 11 increased the content of 2,6-di-tert-butyl-p-cresol from 0.5 parts to 5 parts, and the content of pure water from 26.9 parts to 22.4 parts. The appearance of the groove was the same as that of Example 1, so the content of 2,6-di-tert-butyl-p-cresol was lower than that of Example 1. Comparative Example 10 Compared with Example 1, the content of 2,6-di-tert-butyl-p-cresol was reduced from 0.5 parts to 0.05 parts, and the content of pure water was increased from 26.9 parts to 27.35 parts. After the chip was cut in Comparative Example 10, the cutting groove turned yellow, affecting the appearance of the cutting groove.

[0092] In addition, two types of laser cutting protection liquid purchased on the market (hereinafter referred to as Group A and Group B) are used to form a film on the wafer, and then laser cutting is performed. After cutting, the cutting marks are observed under a microscope. Figure 1 As shown, the wafer protected by Example 1 is cut as follows Figure 2 As shown, the wafer protected by group A is cut as Figure 3 As shown, the wafer protected by group B is cut as Figure 4 As shown. By comparison, the cut in Example 1 is the narrowest and relatively smooth, and there is no variegated color at the edge of the cut. Group B turns yellow seriously after cutting, and the cut is wider than that in Example 1 and Group A. The cut in Group A is the most uneven, and variegated precipitation can be clearly seen at the edge of the cut.

[0093] It can be seen that the embodiment of the present application can reduce the range of the wafer affected by laser thermal radiation, reduce the loss of the cut chip, and when the protected wafer is cut to the required depth by laser, the cut gap is narrow, does not turn yellow, and has no mixed color precipitation. It can provide technical support for making the reserved groove for cutting smaller for the front-end chip.

[0094] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A laser cutting protection liquid, characterized in that: The composition comprises the following components by mass: 5%-10% of AB type block polymer surfactant, 40%-60% of water-soluble polymer, 3%-6% of moisturizer, 0.1%-0.2% of corrosion inhibitor, 0.3%-0.6% of 2-hydroxy-4-n-octyloxybenzophenone, 0.5%-5% of 2,6-di-tert-butyl-p-cresol, 10%-15% of organic detergent, and the balance is water; the AB type block polymer surfactant is a block copolymer of dimethylaminoethyl acrylate and methyl acrylate.

2. The laser cutting protection liquid according to claim 1, characterized in that: The content of the AB type block polymer surfactant in the laser cutting protection liquid is 5%.

3. The laser cutting protection liquid according to claim 1, characterized in that: The water-soluble polymer is polyvinyl alcohol.

4. The laser cutting protection liquid according to claim 3, characterized in that: The content of the water-soluble polymer in the laser cutting protection liquid is 50%.

5. The laser cutting protection liquid according to claim 1, characterized in that: The humectant is polyethylene glycol.

6. The laser cutting protection liquid according to claim 1, characterized in that: The corrosion inhibitor is polyethylene.

7. The laser cutting protection liquid according to claim 1, characterized in that: The organic cleaning agent is propylene glycol methyl ether.

8. The laser cutting protection liquid according to claim 7, characterized in that: The content of the organic cleaning agent in the laser cutting protection liquid is 12%.

9. The laser cutting protection liquid according to claim 1, characterized in that: The content of the 2-hydroxy-4-n-octyloxybenzophenone in the laser cutting protection liquid is 0.5%, and the content of the 2,6-di-tert-butyl-p-cresol in the laser cutting protection liquid is 0.5%.

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