Adhesive film for bonding seed crystals, preparation method and application

Abstract

The invention discloses an adhesive film for bonding seed crystals, a preparation method and application, and the adhesive film for bonding the seed crystals comprises a phenolic resin layer and a photoresist layer which are arranged in sequence. The adhesive film for seed crystal bonding prepared in the invention is a semitransparent adhesive film, the condition of an adhesive layer can be clearly seen, such as whether the adhesive layer is uniform and has areas which do not meet requirements as dust, impurities and bubbles, and the adhesive film can be cut according to the required size and can avoid the areas which do not meet the requirements during use, so that the quality of the adhesive layer can be conveniently controlled, and the service life of the adhesive film is prolonged. Therefore, the bonding yield is improved; and when the adhesive film for bonding the seed crystal is used, the film is directly torn off and is adhered to the seed crystal for hot pressing, so that the adhesive film is convenient to use, the adhesive layer and the seed crystal are relatively uniformly adhered after hot pressing, bubbles are almost not observed by naked eyes, and the bonding yield is relatively high.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon carbide crystal growth, and more particularly to an adhesive film for seed crystal bonding, a preparation method and an application thereof. Background Art

[0002] Currently, the mainstream process for seed crystal bonding mainly uses commercial glue to apply the colloid on the surface of the seed crystal by manual coating, mechanical spraying, spin coating, etc. During this process, the operator needs to detect the quality of the glue layer on the surface of the seed crystal. However, due to the subjective differences in the judgment criteria and methods among different operators, this directly affects the yield rate of the bonding process.

[0003] In addition, there are potential problems in the direct glue coating process, such as impurities in the colloid and uneven thickness of the glue layer. Once such defects occur, the seed crystal needs to be reworked and cleaned, which not only increases the production time cost but also causes a waste of human resources.

[0004] It can be seen that the traditional seed crystal bonding process places high requirements on the professional skills and meticulousness of the operator. At the same time, due to the individual differences among operators and the non-uniformity of judgment criteria, it is difficult to maintain a stable bonding yield rate, which to a certain extent restricts the standardization and consistency of the production process.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide an adhesive film for seed crystal bonding, a preparation method and an application thereof, which are beneficial to improving the bonding yield rate and stability.

[0007] The present invention is implemented as follows:

[0008] In a first aspect, the present invention provides an adhesive film for seed crystal bonding, including a phenolic resin layer and a photoresist layer arranged in sequence.

[0009] In an alternative embodiment, and / or, the thickness of the phenolic resin layer is 40 - 60 um;

[0010] and / or, the thickness of the photoresist layer is 5 - 15 um.

[0011] In an alternative embodiment, a protective film is further provided on the side of the photoresist layer away from the phenolic resin layer;

[0012] A protective film is also provided on the side of the phenolic resin layer away from the photoresist layer;

[0013] An evacuation layer is provided between the protective film and the phenolic resin layer and between the protective film and the photoresist layer.

[0014] In an alternative embodiment, the material of the evacuation layer is at least one of silicone, silicone-based compounds, and fluoropolymers;

[0015] The thickness of the evacuation layer is 10 - 20 μm.

[0016] In a second aspect, the present invention provides a method for preparing the seed crystal bonding adhesive film according to any one of the foregoing embodiments, including:

[0017] Formation of the phenolic resin layer, causing a slurry containing phenolic resin and additives to form a slurry layer, and then subjecting the slurry layer to a first curing to form a phenolic resin layer;

[0018] Formation of the photoresist layer, forming a photoresist layer drying layer on the surface of the phenolic resin layer, and then subjecting the photoresist layer drying layer to a second curing to form a photoresist layer.

[0019] In an alternative embodiment, the temperature of the first curing is 50 - 70 °C;

[0020] And / or, the temperature of the second curing is 18 - 30 °C.

[0021] In an alternative embodiment, the mass ratio of phenolic resin to additives in the slurry is 1:1.3 - 1.7;

[0022] And / or, the additive is ethanol.

[0023] In an alternative embodiment, the slurry layer is formed on the surface of the evacuation layer, and a protective layer is provided on the side of the evacuation layer away from the phenolic resin layer;

[0024] It further includes forming an evacuation layer on the surface of the photoresist layer away from the phenolic resin layer, and a protective layer is provided on the side of the evacuation layer away from the photoresist layer.

[0025] In a third aspect, the present invention provides a method for bonding a seed crystal, including: pasting the adhesive film according to any one of the foregoing embodiments between the seed crystal and the graphite paper and performing hot pressing, wherein the phenolic resin layer of the adhesive film is adhered to the graphite paper, the photoresist layer of the adhesive film is adhered to the seed crystal, and the pressure in the hot pressing step is 900 - 1100 Kg.

[0026] In an alternative embodiment, the protective layer is removed before pasting the adhesive film;

[0027] And / or, the hot pressing is carried out in a five-stage heating manner, including a first-stage heating, a second-stage heating, a third-stage heating, a fourth-stage heating, and a fifth-stage heating;

[0028] Preferably, in the first-stage heating, the temperature is raised from 25 - 30 °C to 90 - 110 °C within 50 - 70 min and kept warm for 25 - 35 min;

[0029] Preferably, the two-stage heating raises the temperature to 140 - 160°C within 110 - 130 min and holds the temperature for 25 - 35 min;

[0030] Preferably, the three-stage heating raises the temperature to 190 - 210°C within 110 - 130 min and holds the temperature for 25 - 35 min;

[0031] Preferably, the four-stage heating raises the temperature to 290 - 310°C within 110 - 130 min and holds the temperature for 25 - 35 min;

[0032] Preferably, the five-stage heating raises the temperature to 410 - 430°C within 110 - 130 min and holds the temperature for 55 - 65 min.

[0033] The present invention has the following beneficial effects:

[0034] The seed crystal bonding adhesive film prepared in this application is a semi-transparent adhesive film, and the situation of the adhesive layer can be clearly seen, such as whether it is uniform, and whether there are areas that do not meet the requirements such as dust, impurities, and bubbles. When in use, the adhesive film can be cut according to the required size and the above-mentioned areas that do not meet the requirements can be avoided, which is convenient for controlling the quality of the adhesive layer, thereby improving the bonding yield.

[0035] When the seed crystal bonding adhesive film prepared in this application is used, the film can be directly torn off and pasted on the seed crystal for hot pressing. It is convenient to use. After hot pressing, the adhesive layer fits evenly with the seed crystal, and almost no bubbles can be observed with the naked eye, and the bonding yield is relatively high. Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 It is a picture of the mixture of phenolic resin powder and ethanol in Example 1 of this application;

[0038] Figure 2 It is a picture of applying the adhesive film prepared in Example 1 to seed crystal bonding in Test Example 1;

[0039] Figure 3 It is a picture of applying the adhesive film prepared in Comparative Example 1 to seed crystal bonding in Test Example 1;

[0040] Figure 4 It is a picture of applying the adhesive film prepared in Comparative Example 2 to seed crystal bonding in Test Example 1;

[0041] Figure 5 The picture showing the application of the adhesive film prepared in Example 1 to seed crystal bonding in Test Example 2. Detailed implementation manners

[0042] When applying glue to the seed crystal by manual smearing or manually operating a machine to spray or spin-coat the glue and then bonding the graphite paper, differences will occur due to different operators' techniques or operation methods. This is not conducive to improving the bonding yield and stability, and has high requirements for the operators' capabilities, which is not conducive to reducing labor costs. At the same time, if there is a little dust or impurity in the glue layer, it has to be scrapped and restarted, greatly limiting the improvement of efficiency and the reduction of costs. In order to improve the bonding yield and stability and reduce the requirements for the operators' capabilities, this application is proposed.

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0044] An embodiment of the present invention provides an adhesive film for seed crystal bonding, which includes a phenolic resin layer and a photoresist layer arranged in sequence.

[0045] The adhesive film for seed crystal bonding in this application is similar to double-sided tape. When in use, only need to stick the adhesive film for seed crystal bonding between the seed crystal and the graphite paper and perform hot pressing, without the need for manual control of smearing or spraying glue, which is conducive to reducing risk points, and the operation is simpler, with lower requirements for the operators' capabilities and is easier to operate.

[0046] The adhesive film for seed crystal bonding in this application is semi-transparent, and it is possible to observe whether there are impurities and whether it is uniform with the naked eye. When in use, the adhesive film can be cut according to the required size and positions with impurities or unevenness can be avoided, which is conducive to improving the bonding quality and yield.

[0047] Both the phenolic resin layer and the photoresist layer in the adhesive film for seed crystal bonding in this application are formed through curing. During curing, a part of the water and organic substances evaporate. When the adhesive film for seed crystal bonding is subsequently stuck between the seed crystal and the graphite paper and hot pressed, the volatilization amount of the organic substances and water is reduced, which is conducive to reducing bubbles and improving the uniformity of the bonding pattern.

[0048] In an optional embodiment, the thickness of the phenolic resin layer is 40 - 60 um;

[0049] And / or, the thickness of the photoresist layer is 5 - 15 um.

[0050] The photoresist layer or the phenolic resin layer having a certain thickness is beneficial to improving the bonding strength. However, since an excessive thickness of the adhesive film for seed crystal bonding will lead to a decrease in the uniformity of the temperature distribution of the seed crystal, and further increase the number of defects generated during the growth process of the seed crystal, the photoresist layer or the phenolic resin layer should not be too thick.

[0051] In an alternative embodiment, a protective film is further provided on a side of the photoresist layer away from the phenolic resin layer;

[0052] A protective film is further provided on a side of the phenolic resin layer away from the photoresist layer;

[0053] An evacuation layer is provided between the protective film and the phenolic resin layer and between the protective film and the photoresist layer.

[0054] Specifically, in some embodiments, the protective film can be a plastic film to prevent dust or other components from contacting the photoresist layer or the phenolic resin layer and affecting the subsequent bonding effect; the evacuation layer is located between the plastic film and the photoresist layer or the phenolic resin layer to prevent adhesion between the protective film and the photoresist layer or the phenolic resin layer, which is beneficial to the separation of the protective film from the photoresist layer or the phenolic resin layer.

[0055] In an alternative embodiment, the evacuation layer is made of at least one of silicone, organosilicon compounds, and fluoropolymers;

[0056] And / or, the thickness of the evacuation layer is 10 - 20 um.

[0057] The evacuation layer has a sufficient thickness to prevent adhesion between the protective film and the photoresist layer or the phenolic resin layer. However, if the evacuation layer is too thick, it will lead to an increase in cost and, at the same time, when bonding, excessive residue of the evacuation layer on the surface of the photoresist layer or the phenolic resin layer will cause a decrease in the bonding strength;

[0058] The embodiments of the present invention also provide a method for preparing the adhesive film for seed crystal bonding according to any one of the foregoing embodiments, including:

[0059] Formation of the phenolic resin layer, forming a slurry layer from a slurry containing phenolic resin and additives, and then performing a first curing on the slurry layer to form a phenolic resin layer;

[0060] Formation of the photoresist layer, forming a to-be-dried layer of the photoresist layer on the surface of the phenolic resin layer, and then performing a second curing on the to-be-dried layer of the photoresist layer to form a photoresist layer.

[0061] The phenolic resin layer and the photoresist layer in the seed crystal bonding adhesive film of the present application are both formed through curing. During curing, a part of the moisture and organic substances evaporate. When the seed crystal bonding adhesive film is subsequently adhered between the seed crystal and the graphite paper and hot-pressed, the volatilization amount of the organic substances and water decreases, which is beneficial to reducing bubbles and improving the uniformity of the bonding lines.

[0062] It should be noted that the viscosity of the phenolic resin used in the present application is too high, which is not conducive to forming a uniform slurry layer. Therefore, mixing the phenolic resin with an auxiliary agent is beneficial to reducing the viscosity of the slurry, and a relatively uniform slurry layer can be formed by spraying, roll coating and other methods. In some embodiments, in order to improve the uniformity of the phenolic resin layer, the slurry layer can be formed multiple times, and each time after the slurry layer is formed, a curing is carried out until the thickness of the formed phenolic resin layer meets the requirements.

[0063] In an alternative embodiment, the first curing temperature is 50 - 70 °C and the time is 50 - 70 s;

[0064] and / or, the second curing temperature is 18 - 30 °C.

[0065] During the curing process, the phenolic resin layer and the photoresist layer are gradually formed, and at the same time, the evaporation of moisture, auxiliary agent and a small amount of organic substances occurs. Compared with directly brushing the adhesive on the seed crystal, the volatilization amount of organic substances and water during subsequent hot pressing decreases, which is beneficial to reducing bubbles and improving the uniformity of the bonding lines.

[0066] In an alternative embodiment, the mass ratio of the phenolic resin to the auxiliary agent in the slurry is 1:1.3 - 1.7;

[0067] and / or, the auxiliary agent is ethanol.

[0068] The auxiliary agent plays a role in diluting the phenolic resin, enabling the formation of a slurry layer by various methods such as spraying, and is beneficial to improving the uniformity of the slurry layer, and further beneficial to improving the uniformity of the phenolic resin layer. However, if the amount of the auxiliary agent is too much, the viscosity of the slurry is too low and the fluidity is too good, which is not conducive to the formation of the phenolic resin layer. It should be noted that ethanol with a lower boiling point is used as the auxiliary agent, and there is less residue after curing. And after adding the auxiliary agent, it may be due to the residue of the auxiliary agent that the bonding ability of the phenolic resin layer is reduced compared with that without adding the auxiliary agent, which is beneficial to reducing the damage to the seed crystal.

[0069] In an alternative embodiment, the slurry layer is formed on the surface of the evacuation layer, and a protective layer is provided on the side of the evacuation layer away from the phenolic resin layer;

[0070] It further includes forming an evacuation layer on the surface of the photoresist layer away from the phenolic resin layer, and a protective layer is provided on the side of the evacuation layer away from the photoresist layer.

[0071] Protective layers are provided on both sides of the seed crystal bonding adhesive film, facilitating the processing of the seed crystal bonding adhesive film and reducing the pollution of the phenolic resin layer and / or the photoresist layer by the outside. The evacuation layer can be applied on the surface of the protective layer or the photoresist by spraying, roll coating or brushing, and the preparation is convenient. It should be noted that the size of the seed crystal bonding adhesive film in this application can be set as required. Under the condition allowed by the equipment, it can be as large as possible. When in use, use scissors to avoid the areas that do not meet the requirements and cut it to the appropriate size.

[0072] The embodiment of the present invention also provides a seed crystal bonding method, including: pasting the adhesive film described in any one of the foregoing embodiments between the seed crystal and the graphite paper and performing hot pressing, wherein the phenolic resin layer of the adhesive film is attached to the graphite paper, and the photoresist layer of the adhesive film is attached to the seed crystal, and the pressure of the hot pressing step is 900-1100 Kg.

[0073] Specifically, the photoresist layer contacts the seed crystal, which can protect the seed crystal and prevent backside corrosion, and the phenolic resin layer contacts the graphite paper.

[0074] In an optional embodiment, the protective layer is removed before the adhesive film is pasted. The evacuation layer will also adhere to the protective layer, so that most of the evacuation layer is removed along with the protective layer, and only a small amount remains on the phenolic resin layer and / or the photoresist layer, which has little impact on the bonding ability of the seed crystal bonding adhesive film.

[0075] In an optional embodiment, the hot pressing is carried out in a five-stage heating manner, including the first-stage heating, the second-stage heating, the third-stage heating, the fourth-stage heating and the fifth-stage heating;

[0076] Preferably, in the first-stage heating, the temperature is raised from 25-30 °C to 90-110 °C within 50-70 min and kept warm for 25-35 min;

[0077] Preferably, in the second-stage heating, the temperature is raised to 140-160 °C within 110-130 min and kept warm for 25-35 min;

[0078] Preferably, in the third-stage heating, the temperature is raised to 190-210 °C within 110-130 min and kept warm for 25-35 min;

[0079] Preferably, in the fourth-stage heating, the temperature is raised to 290-310 °C within 110-130 min and kept warm for 25-35 min;

[0080] Preferably, in the fifth-stage heating, the temperature is raised to 410-430 °C within 110-130 min and kept warm for 55-65 min.

[0081] The advantages of this heating program are as follows:

[0082] 1. Reduce the risk of thermal stress

[0083] The staged heating allows the material to gradually adapt to the temperature change, avoiding excessive thermal stress between the seed crystal and the graphite paper or graphite cover due to the difference in thermal expansion coefficient caused by rapid heating, thereby reducing the risk of cracks or interface delamination.

[0084] 2. Optimize the quality of the bonding layer

[0085] By controlling the heating rate, the adhesive is ensured to be uniformly densified to avoid local sintering that is too fast and causes pores or weak bonding.

[0086] 3. Improve interface bonding strength

[0087] Keeping the temperature at the critical point helps to fully eliminate the volatiles in the bonding layer and reduce defects; the slow heating in the subsequent high-temperature stage promotes atomic diffusion and strengthens the bonding between the seed crystal and the graphite paper.

[0088] 4. Improved process stability

[0089] The staged heating can accurately match the thermal property differences between graphite and SiC, avoid deformation or position shift caused by sudden temperature changes, and ensure bonding repeatability.

[0090] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0091] Example 1

[0092] This embodiment provides a method for preparing a seed crystal bonding film, which specifically includes:

[0093] Use an ultrasonic sprayer to evenly spray silicone on the plastic film as a dispersion layer with a thickness of about 15um;

[0094] Phenolic resin powder (high purity) and ethanol were mixed at a ratio of 1:1.5 by weight to obtain Figure 1 The material is then evenly sprayed on the evacuated layer, and then heated to cure at a temperature of 60°C for 1 minute. The spraying and curing are repeated 3 times to obtain a phenolic resin layer with a thickness of 50 μm.

[0095] Spray photoresist on the phenolic resin layer, and then place it at 25°C for drying and curing for 10 minutes to obtain a photoresist layer with a thickness of 10 μm;

[0096] A plastic film with a dispersion layer is placed on the photoresist layer to obtain a prefabricated seed crystal bonding film.

[0097] Example 2

[0098] This embodiment provides a method for preparing a seed crystal bonding film, which specifically includes:

[0099] Use an ultrasonic spray coater to evenly spray silicone on the plastic film as the evacuation layer, with a thickness of about 10 μm;

[0100] Mix phenolic resin powder (high purity) and ethanol in a weight ratio of 1:1.3 and stir, then evenly spray it on the evacuation layer, and then raise the temperature for curing. The curing temperature is 70 °C and the curing time is 1 min. Spraying and curing are repeated 3 times to obtain a phenolic resin layer with a thickness of 40 μm;

[0101] Spray photoresist on the phenolic resin layer, and then place it at 18 °C for drying and curing for 20 min to obtain a photoresist layer with a thickness of 15 μm;

[0102] Place a plastic film with an evacuation layer on the photoresist layer to obtain a prefabricated seed crystal bonding film.

[0103] Example 3

[0104] This example provides a method for preparing a seed crystal bonding film, specifically including:

[0105] Use an ultrasonic spray coater to evenly spray silicone on the plastic film as the evacuation layer, with a thickness of about 20 μm;

[0106] Mix phenolic resin powder (high purity) and ethanol in a weight ratio of 1:1.7 and stir, then evenly spray it on the evacuation layer, and then raise the temperature for curing. The curing temperature is 50 °C and the curing time is 2 min. Spraying and curing are repeated 3 times to obtain a phenolic resin layer with a thickness of 60 μm;

[0107] Spray photoresist on the phenolic resin layer, and then place it at 30 °C for drying and curing for 10 min to obtain a photoresist layer with a thickness of 5 μm;

[0108] Place a plastic film with an evacuation layer on the photoresist layer to obtain a prefabricated seed crystal bonding film.

[0109] Comparative Example 1

[0110] This comparative example provides a method for preparing a seed crystal bonding film, including:

[0111] Use an ultrasonic spray coater to evenly spray silicone on the plastic film as the evacuation layer, with a thickness of about 15 μm;

[0112] Mix phenolic resin powder, ethanol and photoresist in a weight ratio of 1:1.5:1, then spray it on the evacuation layer, and then cure it at 60 °C for 1 min to obtain a bonding layer with a thickness of 60 μm;

[0113] Place a plastic film with an evacuation layer on the bonding layer to obtain a seed crystal bonding film.

[0114] Comparative Example 2

[0115] This comparative example provides a method for preparing an adhesive film for seed crystal bonding. The difference from Example 1 is only that the photoresist layer is omitted, and a plastic film with a release layer is placed on the prepared phenolic resin layer with a thickness of 60 μm to obtain an adhesive film for seed crystal bonding.

[0116] Comparative Example 3

[0117] This comparative example provides a method for preparing an adhesive film for seed crystal bonding. The difference from Example 1 is only that the phenolic resin layer is omitted, and a photoresist layer is sprayed on the release layer. After curing, a plastic film with a release layer is placed on the photoresist layer with a thickness of 60 μm to obtain an adhesive film for seed crystal bonding.

[0118] Comparative Example 4

[0119] This comparative example provides a method for preparing an adhesive film for seed crystal bonding. The difference from Example 1 is only that ethanol is not added during the formation of the phenolic resin layer. The obtained adhesive film for seed crystal bonding is too viscous to be sprayed, and the uniformity of the phenolic resin layer obtained by manual coating is poor.

[0120] Test Example 1

[0121] This test example provides a method for seed crystal bonding using the adhesive films for seed crystal bonding prepared in the above examples and comparative examples, including: cutting the adhesive film for seed crystal bonding according to the size of the seed crystal or graphite paper, then tearing off the last placed plastic film and sticking it to the designated position of the seed crystal, and then tearing off another plastic film and sticking it to the graphite paper. Among them, the phenolic resin layer of the adhesive film is attached to the graphite paper, and the photoresist layer of the adhesive film is attached to the seed crystal; then hot pressing is carried out, and the heating program of the hot pressing is as shown in Table 1 below, that is: evacuating to reach the target pressure of 1000 Kg within 30 min; then heating to 100 °C in 60 min and holding for 30 min; then heating to 150 °C in 120 min and holding for 30 min; then heating to 200 °C in 120 min and holding for 30 min; then heating to 300 °C in 120 min and holding for 30 min; then heating to 420 °C in 120 min and holding for 60 min; after hot pressing, the seed crystal bonding is completed.

[0122] Table 1

[0123]

[0124]

[0125] Among them, the seed crystal bonding situation in Example 1 is as Figure 2As shown, the lines after the adhesive film is bonded to the seed crystal are fine and uniform. After the seed crystal grows, looking from the back of the ingot at the position of the seed crystal, there is no phenomenon of seed crystal ablation. The seed crystal bonding situations in Example 2 and Example 3 are the same as those in Figure 2 There is no obvious difference.

[0126] The seed crystal bonding is completed using the adhesive film in Comparative Example 1. The bonding situation is as shown in Figure 3 As shown, after the adhesive film is bonded to the seed crystal, there are large and aggregated bubbles on the bonding surface and the bubble distribution is uneven.

[0127] The seed crystal bonding is completed using the adhesive film in Comparative Example 2. The bonding situation is as shown in Figure 4 As shown, after the adhesive film is bonded to the seed crystal, there are relatively large bubbles on the outer circle of the bonding surface, as shown in the red frame. After the seed crystal grows, looking from the back of the ingot at the position of the seed crystal, there is a phenomenon of seed crystal ablation.

[0128] After hot pressing the adhesive film in Comparative Example 3, the lines of the seed crystal are uneven, and the phenomenon of seed crystal ablation is likely to occur after crystal growth.

[0129] The uniformity of the adhesive film in Comparative Example 4 is poor and cannot meet the requirements of seed crystal bonding.

[0130] Experimental Example 2

[0131] This experimental example provides a method for bonding a seed crystal using the adhesive film for seed crystal bonding prepared in Example 1. The difference from Experimental Example 1 is only that the heating program in the hot pressing step is different, as shown in Table 2 specifically, to obtain the adhesive film for seed crystal bonding.

[0132] Table 2

[0133]

[0134]

[0135] The seed crystal bonding situation in Test Example 2 is the same as that in Figure 2 There is no obvious difference.

[0136] Experimental Example 3

[0137] This experimental example provides a method for bonding a seed crystal using the adhesive film for seed crystal bonding prepared in Example 1. The difference from Experimental Example 1 is only that the heating program in the hot pressing step is different, as shown in Table 2 specifically, to obtain the adhesive film for seed crystal bonding.

[0138] Table 3

[0139]

[0140]

[0141] The seed crystal bonding situation in Test Example 3 is the same as that in Figure 2 There is no obvious difference.

[0142] Test Example 4

[0143] This experimental example provides a method for bonding seeds using the seed bonding adhesive film prepared in Example 1. The difference from Experimental Example 1 is only that the heating program in the hot pressing step is different, as shown in Table 2 specifically, and a seed bonding adhesive film is obtained.

[0144] Table 4

[0145] Time min Temperature °C Pressure kg 30 26 1000 30 100 1000 30 100 1000 30 150 1000 20 150 1000 60 200 1000 20 200 1000 60 300 1000 20 300 1000 60 420 1000 60 420 1000

[0146] In this test example, because the heating rate in the hot pressing step is too fast, the gas generated in the adhesive layer cannot be effectively discharged, resulting in bubbles appearing in the middle of the seeds, as Figure 5 shown in the red frame.

[0147] The seed bonding adhesive film prepared in this application is a semi-transparent adhesive film, and the situation of the adhesive layer can be clearly seen, such as whether it is uniform, and whether there are areas that do not meet the requirements such as dust, impurities, and bubbles. When in use, the adhesive film can be cut according to the required size and the above-mentioned areas that do not meet the requirements can be avoided, which is convenient for controlling the quality of the adhesive layer, thereby improving the bonding yield.

[0148] When the seed bonding adhesive film prepared in this application is used, the film can be directly torn off and pasted on the seeds for hot pressing. It is convenient to use. After hot pressing, the adhesive layer fits evenly with the seeds, and almost no bubbles can be observed with the naked eye, and the bonding yield is relatively high.

[0149] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A seed crystal bonding adhesive film, characterized in that, It includes a phenolic resin layer and a photoresist layer arranged in sequence.

2. The seed crystal bonding adhesive film according to claim 1, characterized in that, The thickness of the phenolic resin layer is 40 - 60 um; and / or, the thickness of the photoresist layer is 5 - 15 um.

3. The seed crystal bonding adhesive film according to claim 1, characterized in that, A protective film is also arranged on the side of the photoresist layer away from the phenolic resin layer; A protective film is also arranged on the side of the phenolic resin layer away from the photoresist layer; An evacuation layer is arranged between the protective film and the phenolic resin layer and between the protective film and the photoresist layer.

4. The seed crystal bonding adhesive film according to claim 3, characterized in that, The material of the evacuation layer is at least one of silicone, silicone-based compounds, and fluoropolymers; and / or, the thickness of the evacuation layer is 10 - 20 um.

5. A method for preparing the seed crystal bonding adhesive film according to any one of claims 1-4, characterized in that, It includes: Formation of the phenolic resin layer: A slurry containing phenolic resin and additives forms a slurry layer, and then the slurry layer is subjected to the first curing to form the phenolic resin layer; Formation of the photoresist layer: A photoresist layer drying layer is formed on the surface of the phenolic resin layer, and then the photoresist layer drying layer is subjected to the second curing to form the photoresist layer.

6. The preparation method of the seed crystal bonding adhesive film according to claim 5, characterized in that, The temperature of the first curing is 50 - 70 °C; and / or, the temperature of the second curing is 18 - 30 °C; and / or, the mass ratio of phenolic resin to additives in the slurry is 1:1.3 - 1.7; and / or, the additive is ethanol.

7. The preparation method of the seed crystal bonding adhesive film according to claim 5, characterized in that The slurry layer is formed on the surface of the evacuation layer, and a protective layer is arranged on the side of the evacuation layer away from the phenolic resin layer; It also includes forming an evacuation layer on the surface of the photoresist layer away from the phenolic resin layer, and a protective layer is arranged on the side of the evacuation layer away from the photoresist layer.

8. A seed crystal bonding method, characterized in that It includes: Stick the film as described in any one of claims 1 - 4 between the seed crystal and the graphite paper and perform hot pressing. Among them, the phenolic resin layer of the film is attached to the graphite paper, and the photoresist layer of the film is attached to the seed crystal. The pressure in the hot pressing step is 900 - 1100 Kg.

9. The seed crystal bonding method according to claim 8, characterized in that, Remove the protective layer before sticking the film; and / or, the hot pressing adopts a five-stage heating method, including the first-stage heating, the second-stage heating, the third-stage heating, the fourth-stage heating, and the fifth-stage heating.

10. The seed crystal bonding method according to claim 9, wherein, The first-stage heating rises from 25 - 30 °C to 90 - 110 °C within 50 - 70 min and keeps warm for 25 - 35 min; The second-stage heating rises to 140 - 160 °C within 110 - 130 min and keeps warm for 25 - 35 min; The third-stage heating rises to 190 - 210 °C within 110 - 130 min and keeps warm for 25 - 35 min; The fourth-stage heating rises to 290 - 310 °C within 110 - 130 min and keeps warm for 25 - 35 min; The fifth-stage heating rises to 410 - 430 °C within 110 - 130 min and keeps warm for 55 - 65 min.

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