A method to prevent adjacent chips from sticking together after wafer dicing in FOW process

Abstract

This invention discloses a method for preventing adjacent chips from sticking together after wafer dicing in a FOW (Frost-Wash) process. The wafer dicing employs a two-stage, two-cut method to form the dicing path. This method involves selecting a blade with a thickness D for the second cut, thereby increasing the width G of the final dicing path. This ensures that the bottom sides of the FOW film on opposite sides of the dicing path will not contact each other after extending to their final positions. Wafers diced using this method can avoid chip sticking during long-term storage at room temperature without the need for additional molds or steps. It is highly practical, improves product yield, and significantly reduces production costs.

Description

Technical Field

[0001] This invention relates to a wafer dicing method, and more particularly to a method for preventing adjacent chips from sticking together after wafer dicing in a FOW process, belonging to the field of semiconductor manufacturing technology. Background Technology

[0002] FOW (film on wire) technology is mainly used in multilayer chip packaging (SCSP). By applying low-stress, frictionless bonding materials (such as FOW paste and film) between chips, precise bonding and gap control between chips can be achieved. Using FOW technology can effectively reduce package thickness and volume.

[0003] In the FOW process, such as Figure 1 and Figure 2 As shown, the back side of wafer 1 is bonded to the base film 3 via FOW film 2 and then cut using a cutting tool 4. This cutting creates a dicing channel 5, which separates wafer 1 and FOW film 2 into multiple chips 6 and independent units of the FOW film 2 bonded to the back side of the chips 6. The cutting tool 4 uses a high-speed rotating disk-shaped mechanical blade. In existing technologies, after cutting and leaving the wafer for a period of time, such as... Figure 3 As shown, due to their extensibility, the bottom sides of the adjacent FOW membranes 2 located on both sides of the cutting channel 5 will adhere to each other (e.g. Figure 3 (Location A in the middle), therefore, it will cause product scrap during subsequent chip assembly, resulting in low product yield. To address this, existing technologies need to control the interval between wafer dicing and subsequent chip assembly to within seven days. Wafers that have not completed chip assembly need to be stored at a low temperature below 5°C. The operation control time is strict, the storage is difficult, additional freezing equipment is required, and energy consumption is high.

[0004] Chinese invention patent application CN119181635A, published on December 24, 2024, discloses a wafer dicing method, comprising the following steps: providing a base film, wherein the base film has protrusions on its upper surface, the positions of which correspond to the dicing channels of the wafer to be diced; providing a wafer, a FOW film, and an adhesive, wherein the adhesive covers the upper surfaces of the base film and the protrusions, and the FOW film is disposed on the lower surface of the wafer, the FOW film being connected to the adhesive; dicing the wafer according to a preset dicing channel to dice the wafer into multiple chips, wherein the bottom wall of the dicing channel is at least below the upper surface of the adhesive, and the dicing channel does not cut through the base film; separating the FOW film from the adhesive to obtain multiple units, each unit comprising a chip and a FOW film on the lower surface of the chip.

[0005] While the aforementioned patent documents also address the problem of FOW films adhering to each other, their technical solutions differ from those in this application. Furthermore, the cutting method described in those patent documents requires forming raised strips on the upper surface of the base film, which complicates the production process and increases production costs. This method is not practical in actual mass production.

[0006] In summary, designing a method to prevent adjacent chips from sticking together after wafer dicing in the FOW process, so that the diced wafers can be stored at room temperature for a long time without chip sticking, is a technical problem that urgently needs to be solved. This method should be practical and reduce production costs. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to address the deficiencies in the prior art by providing a method to avoid adjacent chips sticking together after wafer dicing in the FOW process. This method can prevent chip sticking during long-term storage of the diced wafer under normal temperature conditions, which is highly practical and reduces production costs.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: a method to avoid adjacent chips sticking together after wafer dicing in FOW process, wherein the wafer dicing is performed by two-cutting in two stages to form the dicing channel. The method is to select the thickness specification of the cutter used in the second cutting and increase the thickness D of the cutter used in the second cutting to increase the width G of the final dicing channel, so that the bottom sides of the FOW film located on opposite sides of the dicing channel will not contact each other after extending to the final position.

[0009] Preferably, the tool thickness specifications include AA tool, BB tool, CC tool, DD tool and EE tool, wherein the thickness range of AA tool is 15um to 20um; the thickness range of BB tool is 21um to 25um; the thickness range of CC tool is 26um to 30um; the thickness range of DD tool is 31um to 35um; and the thickness range of EE tool is 36um to 40um.

[0010] The cutting tool used in the second cut shall be a CC blade or a blade of higher thickness, that is, a blade with a thickness of 26um or higher.

[0011] Preferably, when selecting a cutting tool, the thickness specification of the tool used for the second cut is selected first, and then the thickness specification of the tool used for the first cut is selected based on the selected thickness specification of the tool used for the second cut, wherein the thickness of the tool used for the first cut is at least 5µm greater than the thickness of the tool used for the second cut.

[0012] Preferably, when selecting the blade thickness specification for the second cut, the final elongation of the bottom side of the FOW film is first calculated, and then the final elongation of the bottom side of the FOW film is multiplied by two to obtain the final elongation of the FOW film on both sides of the cutting track. Finally, the blade thickness specification for the second cut is selected based on the fact that the thickness D of the blade used for the second cut is greater than the final elongation of the FOW film on both sides of the cutting track.

[0013] Preferably, the final elongation of the bottom side of the FOW membrane is calculated using the following formula:

[0014] Final elongation = k × FOW film thickness × CTE / (Tg) 0.5 +a),

[0015] Where CTE is the coefficient of thermal expansion of the FOW film, Tg is the glass transition temperature of the FOW film, k is the elongation coefficient of the FOW film and k=0.52; a is the glass transition correction factor of the FOW film.

[0016] Preferably, when the parameters of the FOW membrane are: Tg=119℃, CTE=63ppm / ℃, FOW membrane thickness=60um, a=142, the final elongation is calculated according to the above formula as 0.52×60×63 / (119℃). 0.5 +142) = 12.9um;

[0017] At this point, based on the final elongation of 12.9um, the final elongation of the FOW film on both sides of the cutting channel is calculated as 12.9um × 2 = 25.8um. ​​According to the thickness specification of the cutting tool, a CC cutting tool is used, that is, the cutting tool thickness range is 26um to 30um.

[0018] After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the CC tool. Therefore, the tool used for the first cut is the DD tool, which has a thickness range of 31um to 35um.

[0019] Preferably, when the FOW membrane parameters are: Tg=130℃, CTE=70ppm / ℃, FOW membrane thickness=60um, a=132, the final elongation is calculated to be 0.52×60×70 / (130 0.5 +132) = 15.2um;

[0020] At this point, based on the final elongation of 15.2um, the final elongation of the FOW film on both sides of the cutting path is calculated as 15.2um × 2 = 30.4um. According to the thickness specification of the cutting tool, a DD cutting tool is used, that is, the cutting tool thickness range is 31um to 35um.

[0021] After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the DD tool. Therefore, the tool used for the first cut is the EE tool, which has a thickness range of 36um to 40um.

[0022] Preferably, when the parameters of the FOW membrane are: Tg=115℃, CTE=59ppm / ℃, FOW membrane thickness=60um, a=134, the final elongation is calculated to be 0.52×60×59 / (115 0.5 +134) = 12.7um;

[0023] At this point, based on the final elongation of 12.7um, the final elongation of the FOW film on both sides of the cutting channel is calculated as 12.7um × 2 = 25.4um. According to the thickness specification of the cutting tool, a CC cutting tool is used, that is, the cutting tool thickness range is 26um to 30um.

[0024] After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the CC tool. Therefore, the tool used for the first cut is the DD tool, which has a thickness range of 31um to 35um.

[0025] Preferably, when the parameters of the FOW membrane are: Tg=215℃, CTE=37ppm / ℃, FOW membrane thickness=100um, a=136, the final elongation is calculated to be 0.52×100×37 / (215 0.5 +136) = 12.8um;

[0026] At this point, based on the final elongation of 12.8um, the final elongation of the FOW film on both sides of the cutting channel is calculated as 12.8um × 2 = 25.6um. According to the thickness specification of the cutting tool, a CC cutting tool is used, that is, the cutting tool thickness range is 26um to 30um.

[0027] After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the CC tool. Therefore, the tool used for the first cut is the DD tool, which has a thickness range of 31um to 35um.

[0028] Preferably, each dicing channel is first cut with a tool of one thickness specification. During the first cut, the cutting reaches the interior of the wafer to form a preliminary dicing channel. Then, a tool of another thickness specification is used to cut along the preliminary dicing channel again. During the second cut, the cutting reaches the interior of the base film, thus forming the final dicing channel.

[0029] Let the thickness of the wafer be H, and the depth to which the tool cuts into the interior of the wafer during the first cut be K, then K = H / 2 to H / 3; let the depth to which the tool cuts into the interior of the base film during the second cut be M, then M is 20um to 30um.

[0030] The beneficial effects of this invention are as follows: Wafers cut using this method can avoid chip adhesion during long-term storage at room temperature, and no additional molds or steps are required, making it highly practical, improving product yield, and significantly reducing production costs. The tool selection method allows for rapid tool selection for different FOW films, thereby improving processing efficiency. By setting the cutting depth, wafer breakage due to cutting can be effectively avoided. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a wafer, FOW film, and substrate film assembly before cutting using a cutting tool in the prior art.

[0032] Figure 2 This is a schematic diagram of the structure after cutting a wafer, FOW film and base film assembly using a cutting tool in the prior art;

[0033] Figure 3 This is a schematic diagram of the structure after cutting a wafer, FOW film and base film assembly with a cutting tool and leaving it for a period of time in the prior art;

[0034] Figure 4 for Figure 3 Enlarged structural diagram of section B;

[0035] Figure 5 This is a schematic diagram of a partial structure at the bottom side of the FOW membrane located on one side of the cutting channel;

[0036] Figure 6 This is a partial structural diagram of the wafer, FOW film, and base film assembly after the first cutting using a cutting tool in an embodiment of the present invention.

[0037] Figure 7 This is a partial structural diagram of the wafer, FOW film, and base film assembly after a second cutting using a cutting tool, as described in an embodiment of the present invention.

[0038] In the diagram: 1. Wafer; 2. FOW film; 211. Bottom side; 3. Base film; 4. Tool; 5. Cutting track; 511. Preliminary cutting track; 6. Chip. Detailed Implementation

[0039] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0040] Example: Figure 4 As shown, the applicant discovered through research that after cutting, the bottom sides of the FOW membrane 2 located on opposite sides of the cutting channel 5 extend towards the middle of the cutting channel 5 in a tendency to move closer together. As shown in the figure, the bottom sides of the FOW membrane 2 located on the right and left sides of the cutting channel 5 are located at line segments C1 and D1 immediately after cutting. As time increases, the bottom side of the FOW membrane 2 located on the right side of the cutting channel 5 will extend from line segment C1 to line segment C2, line segment C3, and finally to line segment C4. Correspondingly, the bottom side of the FOW membrane 2 located on the left side of the cutting channel 5 will extend from line segment D1 to line segment D2, line segment D3, and finally to line segment D4. Thus, when the bottom sides of the FOW membrane 2 located on the right and left sides of the cutting channel 5 extend to line segments C4 and D4 respectively, the two adhere together.

[0041] The final elongation of the bottom side of the FOW membrane is defined below, as follows: Figure 5 As shown, point E is the intersection of the bottom side of the FOW membrane 2 on one side of the cutting channel 5 and the base membrane 3 immediately after cutting. Point F is the intersection of the bottom side of the FOW membrane 2 on one side of the cutting channel 5 and the base membrane 3 when the bottom side of the FOW membrane 2 211 on one side of the cutting channel 5 is extended to its final position. Then, line segment EF is the final extension amount of the bottom side of the FOW membrane.

[0042] In this embodiment, the cutting channel 5 is formed by two-stage cutting, such as... Figure 6 As shown, each dicing groove 5 first uses a tool 4 of a certain thickness to perform a first cut on the combination of wafer 1, FOW film 2 and its base film 3. During the first cut, the cut reaches the interior of wafer 1 to form a preliminary dicing groove 511, and then... Figure 7 As shown, a tool 4 of a different thickness is used to cut again along the initially formed cutting path 511. During the second cut, the cutting reaches the interior of the base film 3, thus forming the final cutting path 5. In this technical field, the tool thickness specifications used include AA, BB, CC, DD, and EE tools. Specifically, the thickness range of the AA tool is 15µm to 20µm; the BB tool is 21µm to 25µm; the CC tool is 26µm to 30µm; the DD tool is 31µm to 35µm; and the EE tool is 36µm to 40µm. Figure 6 and Figure 7As shown, we can see that since the width G of the dicing 5 at the point where the FOW film 2 extends is related to the thickness D of the tool 4 used in the second dicing, the method provided in this embodiment for preventing adjacent chips from sticking together after wafer dicing in the FOW process is to increase the thickness D of the tool 4 used in the second dicing by selecting the appropriate thickness specification. This increases the width G of the dicing 5, ensuring that the bottom sides of the FOW film 2 on opposite sides of the dicing 5 do not contact each other after extending to their final positions, thus preventing them from sticking together. Therefore, wafers diced using this method can avoid chip sticking during long-term storage at room temperature without the need for additional molds or steps. This method is highly practical, improves product yield, and significantly reduces production costs.

[0043] In the prior art, the cutting tool 4 used in the second cutting is mostly a BB cutting tool, that is, the tool thickness is 21um to 25um. This results in the cutting track 5 being too narrow, which causes the chip to stick together. However, in this application, the applicant has found that when the cutting tool 4 used in the second cutting is a CC cutting tool or a tool with a thickness of 26um or more, the chip sticking phenomenon can be effectively avoided.

[0044] In this embodiment, the thickness specification of the tool 4 used for the second cut is first selected. Then, based on the selected thickness specification of the tool 4 used for the second cut, the thickness specification of the tool 4 used for the first cut is selected. The thickness of the tool 4 used for the first cut is at least 5µm greater than the thickness of the tool 4 used for the second cut. For example, assuming the tool 4 used for the second cut is a CC tool (26µm to 30µm), then the tool 4 used for the first cut is a DD tool (31µm to 35µm). Similarly, assuming the tool 4 used for the second cut is a DD tool (31µm to 35µm), then the tool 4 used for the first cut is an EE tool (36µm to 40µm). This selection of the thickness specifications of the two tools further avoids chip adhesion. In this application, the tool rotation speed is between 45000 r / min and 55000 r / min.

[0045] like Figure 6 As shown, let the thickness of wafer 1 be H, and let the depth to which the tool 4 cuts into the interior of wafer 1 during the first cut be K (i.e., K is the distance between the upper surface of the wafer and the bottom of the initially formed kerf). Then K = H / 2 to H / 3; Figure 7As shown, during the second cut, the depth to which the cutter 4 cuts into the interior of the base film 3 is set to M (M is the distance between the upper surface of the base film and the bottom of the cut), then M is 20um to 30um. This setting can effectively avoid wafer breakage caused by cutting.

[0046] Since different types of FOW films are used when producing different chip models, the selection of cutting tools will also differ. Therefore, this embodiment also provides a cutting tool selection method, which can quickly select cutting tools for different FOW films, thereby improving processing efficiency.

[0047] Based on the relationship between the elongation-related parameters of different FOW film models and the final elongation of different FOW film models, the applicant obtained a formula as follows:

[0048] Final elongation = k × FOW film thickness × CTE / (Tg) 0.5 +a),

[0049] Wherein, CTE is the coefficient of thermal expansion of the FOW film, Tg is the glass transition temperature of the FOW film, k is the elongation coefficient of the FOW film and k=0.52; a is the glass transition correction factor of the FOW film, and k and a are values ​​obtained by the applicant based on experience.

[0050] When making the selection, first select the thickness specification of the tool 4 used for the second cut, and then select the thickness specification of the tool 4 used for the first cut.

[0051] For example:

[0052] Option 1: When using Nitto Denko's EM-310WJ1-P FOW membrane, with Tg=119℃, CTE=63ppm / ℃, FOW membrane thickness=60um, a=142, the final elongation is calculated as 0.52×60×63 / (119... 0.5 +142) = 12.9um.

[0053] At this point, based on the final elongation of 12.9µm, the tool 4 to be used for the second cut is selected, such as... Figure 5 and Figure 7As shown, knowing the final elongation of the FOW film, in order to prevent the bottom sides of the FOW film 2 located on opposite sides of the cutting track 5 from elongating and sticking together, it is sufficient to make the width G of the cutting track 5 after cutting greater than the final elongation of the FOW film on both sides. That is, the thickness D of the tool 4 used in the second cutting is greater than the final elongation of the FOW film on both sides. The final elongation of the FOW film on both sides = 12.9um × 2 = 25.8um. ​​Therefore, it is sufficient to make the thickness D of the tool 4 used in the second cutting greater than 25.8um. ​​According to the thickness specification of the tool, a CC tool can be used, that is, the tool thickness range is 26um to 30um.

[0054] After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the CC tool. Therefore, the tool for the first cut can be a DD tool, that is, the thickness range is 31um to 35um.

[0055] Option 2: When using Hitachi's HR-400-S41 FOW membrane, with Tg=130℃, CTE=70ppm / ℃, FOW membrane thickness=60um, and a=132, the final elongation is calculated to be 0.52×60×70 / (130...). 0.5 +132) = 15.2um.

[0056] At this point, based on the final elongation of 15.2µm, the tool 4 to be used for the second cut is selected, such as... Figure 5 and Figure 7 As shown, knowing the final elongation of the FOW film, in order to prevent the bottom sides of the FOW film 2 located on opposite sides of the cutting track 5 from elongating and sticking together, it is sufficient to make the width G of the cutting track 5 after cutting greater than the final elongation of the FOW film on both sides. That is, the thickness D of the tool 4 used in the second cutting is greater than the final elongation of the FOW film on both sides. The final elongation of the FOW film on both sides = 15.2um × 2 = 30.4um. Therefore, it is sufficient to make the thickness D of the tool 4 used in the second cutting greater than 30.4um. According to the thickness specification of the tool, a DD tool can be used, that is, the tool thickness range is 31um to 35um.

[0057] After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the DD tool. Therefore, the tool for the first cut can be an EE tool, that is, the thickness range is 36um to 40um.

[0058] Option 3: When using Nitto Denko's EM-310WAJ1-P FOW membrane, with Tg=115℃, CTE=59ppm / ℃, FOW membrane thickness=60um, and a=134, the final elongation is calculated to be 0.52×60×59 / (115...). 0.5 +134) = 12.7um.

[0059] At this point, based on the final elongation of 12.7µm, the tool 4 to be used for the second cut is selected, such as... Figure 5 and Figure 7 As shown, knowing the final elongation of the FOW film, in order to prevent the bottom sides of the FOW film 2 located on opposite sides of the cutting track 5 from stretching and sticking together, it is only necessary to make the width G of the cutting track 5 after cutting greater than the final elongation of the FOW film on both sides. That is, the thickness D of the blade 4 used in the second cutting is greater than the final elongation of the FOW film on both sides. The final elongation of the FOW film on both sides = 12.7um × 2 = 25.4um. Therefore, it is only necessary to make the thickness D of the blade 4 used in the second cutting greater than 25.4um. According to the thickness specification of the blade, a CC blade can be used, that is, the blade thickness range is 26um to 30um.

[0060] After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the CC tool. Therefore, the tool for the first cut can be a DD tool, that is, the thickness range is 31um to 35um.

[0061] Option 4: When using Henkel's CDF20260-20H FOW membrane, with Tg=215℃, CTE=37ppm / ℃, FOW membrane thickness=100um, a=136, the final elongation is calculated to be 0.52×100×37 / (215) 0.5 +136) = 12.8um.

[0062] At this point, based on the final elongation of 12.8µm, the tool 4 to be used for the second cut is selected, such as... Figure 5 and Figure 7As shown, knowing the final elongation of the FOW film, in order to prevent the bottom sides of the FOW film 2 located on opposite sides of the cutting track 5 from stretching and sticking together, it is sufficient to make the width G of the cutting track 5 after cutting greater than the final elongation of the FOW film on both sides. That is, the thickness D of the tool 4 used in the second cutting is greater than the final elongation of the FOW film on both sides. The final elongation of the FOW film on both sides = 12.8um × 2 = 25.6um. Therefore, it is sufficient to make the thickness D of the tool 4 used in the second cutting greater than 25.6um. According to the thickness specification of the tool, a CC tool can be used, that is, the tool thickness range is 26um to 30um.

[0063] After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the CC tool. Therefore, the tool for the first cut can be a DD tool, that is, the thickness range is 31um to 35um.

[0064] The applicant conducted experiments to compare and analyze the original and improved solutions. The experimental data is shown in the table below:

[0065]

[0066] In the table above, Z1 represents the tool used for the first cut and Z2 represents the tool used for the second cut. As can be seen from the data in the table, when the thickness specification of the tool used for the second cut is a CC blade or a blade of CC blade or higher, the phenomenon of chip adhesion can be effectively avoided.

[0067] In summary, wafers cut using this method can avoid chip adhesion issues during long-term storage at room temperature, without requiring additional molds or steps. This method is highly practical, improves product yield, and significantly reduces production costs. The tool selection method allows for rapid tool selection based on different FOW films, thereby improving processing efficiency. By setting the cutting depth, wafer breakage due to cutting can be effectively avoided.

[0068] In the embodiments, "multiple" refers to "two or more". The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the protection scope of the invention, which is defined by the claims.

Claims

1. A method for preventing adjacent chips from sticking together after wafer dicing in a FOW process, wherein the wafer dicing is performed using a two-stage, two-cut method to form the dicing path, characterized in that: The method involves selecting the thickness specification of the tool used in the second cut, increasing the thickness D of the tool used in the second cut, thereby increasing the width G of the final cut, so that the bottom sides of the FOW film located on opposite sides of the cut will not contact each other after extending to the final position. The tool thickness specifications include AA tools, BB tools, CC tools, DD tools, and EE tools. Among them, the thickness range of AA tools is 15um to 20um; the thickness range of BB tools is 21um to 25um; the thickness range of CC tools is 26um to 30um; the thickness range of DD tools is 31um to 35um; and the thickness range of EE tools is 36um to 40um. The blade used in the second cut shall be a CC blade or a blade of higher thickness, that is, a blade with a thickness of 26um or higher. When selecting cutting tools, first select the thickness specification of the tool used for the second cut, and then select the thickness specification of the tool used for the first cut based on the selected thickness specification of the tool used for the second cut. The thickness of the tool used for the first cut should be at least 5µm greater than the thickness of the tool used for the second cut. When selecting the blade thickness specification for the second cut, first calculate the final extension of the bottom side of the FOW film, then multiply the final extension of the bottom side of the FOW film by two to obtain the final extension of the FOW film on both sides of the cutting track. Finally, based on the fact that the thickness D of the blade used for the second cut is greater than the final extension of the FOW film on both sides of the cutting track, select the blade thickness specification for the second cut. The final elongation of the bottom side of the FOW membrane is calculated using the following formula: Final elongation = k × FOW film thickness × CTE / (Tg) 0.5 +a), Where CTE is the coefficient of thermal expansion of the FOW film, Tg is the glass transition temperature of the FOW film, k is the elongation coefficient of the FOW film and k=0.52; a is the glass transition correction factor of the FOW film. Each dicing channel is first cut with a tool of one thickness. During the first cut, the cutting reaches the interior of the wafer to form a preliminary dicing channel. Then, a tool of another thickness is used to cut along the preliminary dicing channel again. During the second cut, the cutting reaches the interior of the base film, thus forming the final dicing channel. Let the thickness of the wafer be H, and the depth to which the tool cuts into the interior of the wafer during the first cut be K, then K = H / 2 to H / 3; let the depth to which the tool cuts into the interior of the base film during the second cut be M, then M is 20um to 30um.

2. The method according to claim 1, characterized in that: When the parameters of the FOW membrane are: Tg=119℃, CTE=63ppm / ℃, FOW membrane thickness=60um, a=142, the final elongation is calculated according to the above formula as 0.52×60×63 / (119 0.5 +142) = 12.9um; At this point, based on the final elongation of 12.9um, the final elongation of the FOW film on both sides of the cutting channel is calculated as 12.9um × 2 = 25.8um. ​​According to the thickness specification of the cutting tool, a CC cutting tool is used, that is, the cutting tool thickness range is 26um to 30um. After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the CC tool. Therefore, the tool used for the first cut is the DD tool, which has a thickness range of 31um to 35um.

3. The method according to claim 1, characterized in that: When the FOW membrane parameters are: Tg = 130℃, CTE = 70ppm / ℃, FOW membrane thickness = 60µm, a = 132, the final elongation is calculated to be 0.52 × 60 × 70 / (130 0.5 +132) = 15.2um; At this point, based on the final elongation of 15.2um, the final elongation of the FOW film on both sides of the cutting path is calculated as 15.2um × 2 = 30.4um. According to the thickness specification of the cutting tool, a DD cutting tool is used, that is, the cutting tool thickness range is 31um to 35um. After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the DD tool. Therefore, the tool used for the first cut is the EE tool, which has a thickness range of 36um to 40um.

4. The method according to claim 1, characterized in that: When the parameters of the FOW membrane are: Tg=115℃, CTE=59ppm / ℃, FOW membrane thickness=60um, a=134, the final elongation is calculated to be 0.52×60×59 / (115 0.5 +134) = 12.7um; At this point, based on the final elongation of 12.7um, the final elongation of the FOW film on both sides of the cutting channel is calculated as 12.7um × 2 = 25.4um. According to the thickness specification of the cutting tool, a CC cutting tool is used, that is, the cutting tool thickness range is 26um to 30um. After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the CC tool. Therefore, the tool used for the first cut is the DD tool, which has a thickness range of 31um to 35um.

5. The method according to claim 1, characterized in that: When the parameters of the FOW membrane are: Tg=215℃, CTE=37ppm / ℃, FOW membrane thickness=100um, a=136, the final elongation is calculated to be 0.52×100×37 / (215 0.5 +136) = 12.8um; At this point, based on the final elongation of 12.8um, the final elongation of the FOW film on both sides of the cutting channel is calculated as 12.8um × 2 = 25.6um. According to the thickness specification of the cutting tool, a CC cutting tool is used, that is, the cutting tool thickness range is 26um to 30um. After selecting the tool for the second cut, select the tool for the first cut based on the selected tool for the second cut. That is, add 5um to the thickness of the CC tool. Therefore, the tool used for the first cut is the DD tool, which has a thickness range of 31um to 35um.

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