Substrate thinning method
By optimizing the coating method of the substrate during the semiconductor manufacturing process, the edge area of the protective film is made flatter, and after grinding and cleaning and light source irradiation, the problem of the protective film being difficult to separate from the substrate is solved, and the smooth reduction of the substrate is achieved. Thinning and subsequent processing can proceed normally.
Patent Information
- Application Number
- CN202410542910.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-30
- Publication Date
- 2025-01-24
AI Technical Summary
During semiconductor manufacturing, during thinning of the substrate, it is difficult for the protective film to separate from the substrate, resulting in problems such as substrate fragmentation and protection film residue.
By attached a protective film on the first surface of the substrate, the top surface of the edge area is flatter, and the surface of the edge surface is cleaned after grinding, and the viscosity of the protective film is used to ensure its smooth removal.
It effectively solves the problem that the protective film is difficult to separate from the substrate, ensure the smooth loss of the substrate and the normal proceeding of subsequent processing, and avoid the residue of the substrate fragments and the protective film.
Smart Images
Figure CN119361507A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of semiconductor technology, and in particular to a substrate thinning method. Background Art
[0002] With the continuous development of semiconductor technology, based on the requirements for the electrical performance of devices, more and more products need to use thinning processes to reduce the thickness of the substrate during their manufacturing process so that the formed devices can achieve the expected electrical parameters. For example, in the preparation process of IGBT chips, backside grinding and backside metallization are crucial steps. Backside grinding can increase the flexibility of the chip, reduce the thermal impedance of the chip, and reduce the chip size. Backside metallization is conducive to achieving better heat dissipation and conductive effects.
[0003] Before the thinning process is performed, a film is usually applied to the front of the substrate to protect the front of the substrate, and then the back of the substrate is ground and thinned, and then the film is torn off, and the rest of the processing is continued. However, during the film tearing process, the protective film is often difficult to separate from the substrate, and even the substrate is brought into the roller of the film tearing equipment with the peeled protective film and is broken into pieces. Summary of the invention
[0004] The object of the present invention is to provide a method for thinning a substrate, and to solve the problem that a protective film is difficult to separate from a substrate during a film peeling process by optimizing a film sticking method.
[0005] In order to solve the above technical problems, the present invention provides a method for thinning a substrate, comprising: attaching a protective film on the first surface of the substrate, wherein the top surface of the protective film located in the edge area of the substrate is flatter than the top surface of the protective film located in the inner area of the substrate; placing the substrate on a grinding table with its first surface facing the grinding table, and performing a grinding process on the second surface of the substrate to thin the thickness of the substrate; cleaning at least the edge portion of the protective film to remove grinding debris on the protective film; and irradiating the protective film with a specific light source to reduce the viscosity of the protective film on the substrate, and then removing the protective film.
[0006] Optionally, the method of attaching a protective film on the first surface of the substrate includes: forming a dielectric layer on the first surface of the substrate and removing a portion of the dielectric layer covering an edge area of the substrate; and attaching a protective film on the first surface of the substrate, wherein the edge of the protective film is attached to the edge area of the substrate, so that the top surface of the protective film located in the edge area of the substrate is flatter than the top surface of the protective film located in the inner peripheral area of the substrate.
[0007] Optionally, the method for preparing the dielectric layer includes: coating a photoresist layer on the first surface of the substrate; performing an edge washing process to remove a portion of the photoresist layer in the edge area of the substrate; and performing a photolithography process to pattern the photoresist layer in the inner peripheral area of the substrate to form a capping pattern covering each chip area.
[0008] Optionally, the substrate has multiple chip areas, the chip area inside the substrate is a valid chip area, and the chip area at the edge of the substrate is an invalid chip area. The area of the invalid chip area constitutes the edge area of the substrate, the part of the dielectric layer covering the invalid chip area is removed, and the part of the protective film covering the edge area forms a concave ring structure.
[0009] Optionally, the protective film is completely attached to the edge area of the substrate.
[0010] Optionally, the protective film covers a portion of the edge region of the substrate, so that an end of the protective film is retracted relative to an outer side wall of the substrate.
[0011] Optionally, the inward dimension of the end of the protective film relative to the outer side wall of the substrate is less than 3 mm.
[0012] Optionally, the method for cleaning the edge portion of the protective film includes: spraying a cleaning liquid onto the top surface and the side wall of the edge portion of the protective film using a nozzle, and brushing the cleaning liquid using a cleaning brush.
[0013] Optionally, the nozzle and the cleaning brush are synchronously moved from the inner side to the outer side of the substrate for brushing, so as to sequentially clean the top surface of the protective film and the side wall of the protective film.
[0014] Optionally, during the grinding process, the method further includes: spraying a cleaning liquid onto the periphery of the substrate to remove grinding debris accumulated on the periphery of the substrate.
[0015] Optionally, the protective film is a UV film, and before removing the protective film, the protective film is irradiated with a UV light source to reduce the viscosity of the protective film.
[0016] In the film laminating method for a substrate provided by the present invention, the top surface of the protective film located in the edge area of the substrate is relatively flat by improving the protective film on the substrate. Therefore, after grinding the substrate, the edge surface of the protective film can be cleaned to facilitate the removal of grinding debris adhering to the edge surface, so that the edge portion of the protective film will not be blocked by the grinding debris during the light source irradiation before the film is removed and can be fully irradiated, ensuring that the protective film can be removed smoothly when the film is removed. In particular, since the edge portion of the protective film is flatly attached to the edge area of the substrate, it will not be hindered by the step when cleaning the protective film, avoiding the problem that the grinding debris is easily accumulated at the corner position of the step due to the existence of the step and is difficult to be removed, so that the grinding debris can be easily removed. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 A schematic diagram of a substrate with a protective film attached.
[0018] Figure 2 For Figure 1 Schematic diagram of the substrate being polished.
[0019] Figure 3 for Figure 1 A schematic diagram of a substrate with grinding debris remaining after grinding is shown.
[0020] Figure 4 It is a schematic flow chart of a method for thinning a substrate in one embodiment of the present invention.
[0021] Figure 5 FIG. 4 is a schematic diagram of an edge region of a substrate in an embodiment of the present invention.
[0022] Figure 6 The figure is a schematic structural diagram of a substrate to be polished with a protective film attached thereto in one embodiment of the present invention.
[0023] Figure 7 For Figure 6 Schematic diagram of the substrate being polished.
[0024] Figure 8 Another schematic diagram of the structure of a substrate to be polished with a protective film attached thereto in one embodiment of the present invention.
[0025] Fig. 9 For Figure 8 Schematic diagram of the substrate being polished.
[0026] Fig.10 It is a schematic structural diagram of a grinding device in one embodiment of the present invention.
[0027] Fig.11 and Fig.12It is a schematic diagram of cleaning a substrate in one embodiment of the present invention.
[0028] The reference numerals are as follows:
[0029] 10 / 100-substrate;
[0030] 100A-Inner area;
[0031] 100B - marginal area;
[0032] 11 / 110- dielectric layer;
[0033] 12 / 120-protective film;
[0034] 20-grinding table;
[0035] 30- grinding head;
[0036] 41-first nozzle;
[0037] 42-second nozzle;
[0038] 50-grinding debris;
[0039] 61- cleaning brush;
[0040] 62- The third nozzle. DETAILED DESCRIPTION
[0041] As described in the background art, a protective film is required to protect the unpolished surface of the substrate during the grinding operation, and the protective film is removed after the grinding operation. However, the protective film is difficult to separate from the substrate during the removal process.
[0042] In this regard, the inventors of the present invention have discovered through research that an important reason why the protective film is difficult to separate from the substrate during peeling is that during the peeling operation, the viscosity between the protective film at the edge of the substrate and the substrate is still relatively high, making it difficult to separate the protective film.
[0043] For details, please refer to Figure 1 As shown in FIG. 1 , a plurality of film layers (e.g., dielectric layer 11) are usually formed on the surface of substrate 10, so that steps are generated on the surface of substrate 10. When protective film 12 is attached, the protective film 12 will conform to the steps and generate steps accordingly. When performing the grinding operation, the side of substrate 10 with protective film 12 attached is placed on grinding table 20 with the side facing the grinding table 20 (e.g., Figure 2As shown in FIG. 1 , at this time, due to the presence of the step, there is a gap between the protective film 12 at some positions and the table surface of the grinding table 20, especially the gap between the protective film 12 at the edge of the substrate and the grinding table 20 is also exposed laterally, so that the grinding debris 50 generated during the grinding process can easily enter from the edge of the substrate 10 and accumulate on the protective film 12 at the edge of the substrate. For example, a large amount of silicon powder will be generated during the grinding process of silicon wafers, and the silicon powder can easily contact the top surface at the edge of the protective film.
[0044] After the grinding operation is completed, the protective film 12 is irradiated with a specific light source to reduce the viscosity of the protective film 12 on the substrate 10, so as to facilitate the protective film 12 to be removed from the substrate 10. However, since grinding debris 50 generated during the grinding process is accumulated on the protective film 12 at the edge of the substrate, the protective film 12 at the edge is not fully irradiated under the cover of the grinding debris 50, resulting in the viscosity between the edge of the protective film 12 and the substrate 10 is still relatively large and difficult to be separated.
[0045] To this end, in the substrate thinning method provided by the present invention, the protective film on the substrate is creatively optimized to avoid the problem that the edge portion of the protective film cannot be separated from the substrate during the film peeling process due to the difficulty in fully irradiating the edge portion of the protective film.
[0046] Specifically, a method for thinning a substrate provided by the present invention may include: attaching a protective film on the first surface of the substrate, wherein the top surface of the protective film located in the edge area of the substrate is flatter than the top surface of the protective film located in the inner area of the substrate; placing the substrate on a grinding table with its first surface facing the grinding table, and performing a grinding process on the second surface of the substrate to thin the thickness of the substrate; cleaning at least the edge portion of the protective film to remove grinding debris on the protective film; and irradiating the protective film with a specific light source to reduce the viscosity of the protective film on the substrate, and then removing the protective film.
[0047] That is, in the thinning method provided by the present invention, the protective film is provided with a flat edge surface, so that after grinding the substrate, the edge surface of the protective film can be cleaned to facilitate the removal of grinding debris adhering to the edge surface, thereby avoiding the problem that the grinding debris is easily accumulated at the corner of the step and is difficult to remove due to the presence of the step. Therefore, in the light source irradiation before the film is removed, the edge portion of the protective film can be fully irradiated without being blocked by the grinding debris, ensuring that the protective film can be removed smoothly when the film is removed.
[0048] Furthermore, the dielectric layer in the edge region of the substrate can be removed so that there is no large step in the edge region of the substrate and a relatively flat surface is formed, so that when the protective film is attached, the protective film can have a corresponding flat edge surface.
[0049] Furthermore, the dielectric layer formed on the substrate may specifically include an organic material layer, which covers the chip area in the inner peripheral area of the substrate to seal and protect the device structure in the chip area. For example, the method for preparing the dielectric layer may include: first, coating a photoresist layer on the substrate; then, using an edge cleaning process (EBR) to remove the portion of the photoresist layer in the edge area of the substrate; then, performing a photolithography process to pattern the photoresist layer in the inner peripheral area of the substrate to form a capping pattern covering each chip area.
[0050] The following is a further detailed description of a substrate thinning method proposed in the present invention in conjunction with specific embodiments. According to the following description, the advantages and features of the present invention will become clearer. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. It should be recognized that relative terms such as "above", "below", "top", "bottom", "above" and "below" shown in the drawings can be used to describe the relationship between various elements. These relative terms are intended to cover different orientations of elements other than the orientations depicted in the drawings. For example, if the device is inverted relative to the view in the drawing, an element described as being "above" another element will now be below the element.
[0051] Figure 4 The schematic diagram of the process of the substrate thinning method in one embodiment of the present invention is as follows. Figure 4 The thinning method shown is used as an example to explain the thinning process in this embodiment. In practical applications, the thinning method can be applied to the thinning process of a substrate formed with an IGBT chip, for example.
[0052] First, step S100 is performed to provide a substrate 100, and a protective film 120 is attached to a first surface of the substrate 100, wherein the top surface of the protective film 120 located in the edge area 100B of the substrate 100 is flatter than the top surface of the protective film 120 located in the inner area 100A of the substrate 100.
[0053] Specifically, the substrate 100 has a first surface and a second surface opposite to each other, the first surface is, for example, the front side of the substrate 100, and the second surface is the back side of the substrate 100. In this embodiment, a protective film 120 is attached to the front side of the substrate 100 to protect the front side structure of the substrate 100 when the back side of the substrate 100 is subsequently ground.
[0054] Furthermore, the substrate 100 also has a plurality of chip areas. Specifically, among the chip areas arranged on the substrate 100, due to the limitations of the substrate shape and the chip shape, the chip area located at the edge of the substrate is usually an incomplete chip area, that is, an invalid chip area. Therefore, the chip area located inside the substrate is usually a valid chip area, and the chip area located at the edge of the substrate is usually an invalid chip area. In this case, the area of the invalid chip area at the edge of the substrate can be defined as the edge area 100B of the substrate 100. For example, the width of the invalid chip area at the edge of the substrate is 3 mm. In this case, the width area of the substrate 100 from the edge to the inside of 3 mm can be defined as the edge area 100B of the substrate, and the inner side of the edge area 100B is the inner surrounding area 100A, and the inner surrounding area 100A has a plurality of valid chip areas.
[0055] For example, Figure 5 In the example, the substrate 100 is specifically a wafer, wherein the chips arranged at the edge of the wafer are invalid chips, and the area occupied by the invalid chips can be defined as the edge area 100B of the wafer.
[0056] When attaching the protective film 120, the portion of the protective film 120 covering the edge region 100B of the substrate 100 may have a relatively flat surface. In a specific example, the method of attaching the protective film 120 on the first surface of the substrate 100 may include: forming a dielectric layer 110 on the first surface of the substrate 100, and removing the portion of the dielectric layer 110 covering the edge region 100B of the substrate; and attaching the protective film 120 on the first surface of the substrate 100, with the edge of the protective film 120 being attached to the edge region of the substrate 110, so that the top surface of the protective film 120 located in the edge region 100B of the substrate is flatter than the top surface of the protective film 120 located in the inner region 100A of the substrate.
[0057] Specifically, the dielectric layer 110 formed on the substrate 100 is usually patterned to form a capping pattern covering each effective chip area in the substrate 100, so the thickness of the dielectric layer 110 is generally large. By removing the dielectric material in the edge area 100B of the substrate, the edge area 100B of the substrate 100 does not have a dielectric layer, so that it can present a relatively flat surface, and then the edge portion of the protective film 120 can also have a flat surface accordingly, specifically, it can present a flat concave ring surface (the concave ring is relative to the protective film 120 in the inner area 100A). In other words, the edge of the protective film 120 is not covered with the dielectric layer, which avoids the formation of steps with inconsistent heights at the edge portion of the protective film 120, thereby solving the problem that contaminants are easily accumulated at the corners of the steps and are difficult to remove, so that the contaminants adhering to the top surface of the edge of the protective film 120 can be easily removed by cleaning.
[0058] Combine the following Figure 5-Figure 6 and Figure 8 , an example is given to illustrate a method for attaching the protective film 120 in one embodiment.
[0059] First, a photoresist layer is coated on the first surface of the substrate 100. The material of the photoresist layer may include photosensitive polyimide. The photoresist layer is used to be patterned in a subsequent step to form a capping pattern covering each effective chip area of the substrate 100. In this embodiment, before the photoresist layer is patterned, an edge cleaning process (EBR) is also performed on the photoresist layer to remove the edge portion of the photoresist layer, as described below.
[0060] Next, an edge cleaning process (EBR) is performed to remove the portion of the photoresist layer covering the edge region 100B of the substrate. After the edge cleaning process, the photoresist layer is only left in the inner region 100A of the substrate 100 to cover the effective chip region.
[0061] As described above, the chips in the edge region 100B of the substrate 100 are usually invalid chips, so although the portion of the photoresist layer at the edge of the substrate is removed in this embodiment, it still does not affect the chip yield. In addition, after removing the edge portion of the photoresist layer, the edge region of the substrate has a relatively flat annular surface.
[0062] Next, a photolithography process is performed to pattern the photoresist layer in the inner peripheral area 100B of the substrate to form a capping pattern covering each chip area for sealing and protecting the device structure in the chip area. Thus, a dielectric layer 110 is formed which is only located in the inner peripheral area 100A of the substrate and is patterned into a plurality of capping patterns.
[0063] Next, continue to refer to Figure 6 and Figure 8 As shown, a protective film 120 is attached to the first surface of the substrate 100 , and the edge of the protective film 120 is attached to the surface of the edge region 100B of the substrate 100 , so that the edge of the protective film 120 has a flat surface.
[0064] In one example, for example Figure 6 As shown, the protective film 120 is completely attached to the edge area 100B of the substrate. In another example, for example Figure 8 As shown, the protective film 120 extends from the inside of the substrate to cover part of the edge area 100B, so that the end of the protective film 120 is retracted relative to the outer wall of the substrate. It should be recognized that the retracted dimension of the end of the protective film 120 is smaller than the width dimension of the edge area 100B of the substrate. For example, if the width dimension of the edge area 100B of the substrate is 3mm, then the retracted dimension of the end of the protective film 120 is less than 3mm. It should be noted that in Figure 8In the example, since the end of the protective film 120 is retracted, the grinding debris adhering to the side wall of the protective film 120 can be reduced during the subsequent grinding process, and the use of the protective film material can also be reduced, which is beneficial to saving costs.
[0065] In this embodiment, before attaching the protective film 120 to the substrate 100, a portion of the dielectric layer 110 located in the edge area 100B of the substrate is removed, so that a portion of the dielectric layer 110 located in the inner area 100A of the substrate is retained to cover the device structure in the effective chip area, thereby achieving closed protection for the device structure, thereby satisfying the closed protection of the effective chip area while also making the edge surface of the substrate 100 flat.
[0066] In this way, when attaching the protective film 120, the edge of the protective film 120 can be attached to the relatively flat edge area 100B of the substrate 100, avoiding the edge of the protective film 120 having a step structure due to being covered with a dielectric layer, thereby effectively improving the problem that pollutants are accumulated at the corners of the steps and are difficult to remove. That is, after the substrate 100 is thinned, the edge of the protective film 120 can be cleaned, and the grinding debris on the top surface of the edge of the protective film 120 can be easily removed, ensuring that the edge of the protective film 120 can also be fully illuminated by the light source, and then the protective film 120 can be smoothly removed from the substrate 100, and the details can be referred to step S200 and step S300.
[0067] In step S200, reference Figure 7 and Fig. 9 As shown, the substrate 100 is placed on the table of the grinding table 20 with its first surface facing the grinding table 20. At this time, there is a gap between the edge surface of the protection film 120 and the table of the grinding table 20, and the gap is exposed laterally.
[0068] In step S300, the second surface of the substrate 100 is ground to reduce the thickness of the substrate 100. In this process, since there is a gap between the edge surface of the protective film 120 and the table surface of the grinding table 20, the grinding debris 50 generated during the grinding process (for example, silicon powder generated when grinding a silicon wafer) can easily enter the gap and further adhere to the top surface of the protective film 120.
[0069] In a further solution, during the grinding process, a cleaning liquid may be sprayed on the periphery of the substrate 100 to promptly remove the grinding debris 50 generated by grinding, thereby preventing the grinding debris 50 from accumulating in large quantities on the periphery of the substrate 100, and improving the problem that the grinding debris 50 easily enters the gap between the protective film and the table. In addition, by cleaning the periphery of the substrate 100, the grinding debris 50 adhering to the outer wall of the substrate 100 can also be removed, effectively preventing the grinding debris 50 from being brought into the subsequent process along with the substrate 100 and causing pollution to the processing equipment and processing environment in the subsequent process.
[0070] Fig.10 The following diagram shows some structures of the grinding equipment, such as Fig.10 As shown, the grinding device may include a grinding table 20, a grinding head 30, a first nozzle 41 and a second nozzle 42. The grinding table 20 is used to place the substrate 100; the grinding head 30 is used to grind the surface of the substrate 100; the first nozzle 41 is used to spray the grinding liquid onto the second surface of the substrate 100 to cooperate with the grinding head 30 to grind the substrate 100; the second nozzle 42 is used to spray the cleaning liquid onto the periphery of the substrate 100 to timely remove the grinding debris 50 generated during the grinding process. Further, the first nozzle 41 and the second nozzle 42 can be connected to the same liquid pipeline, so that the same cleaning liquid or grinding liquid can be sprayed. Alternatively, the first nozzle 41 and the second nozzle 42 can also be connected to different liquid pipelines respectively to control the liquid sprayed by the first nozzle 41 and the second nozzle 42 respectively.
[0071] After grinding the substrate 100 , the ground substrate may be subjected to surface treatment by etching, for example, SEZ treatment may be performed on the substrate 100 to reduce damage to the substrate surface and improve thickness uniformity during the thinning process.
[0072] Then, step S400 is performed to clean at least the edge of the protective film 120 to remove the grinding debris 50 on the protective film 120. As described above, there is a gap exposed laterally between the edge of the protective film 120 and the table surface of the grinding table 20, so that the grinding debris 50 generated during the grinding process can easily enter the gap and adhere to the edge of the protective film 120. Therefore, by cleaning the edge of the protective film 120 to remove the grinding debris 50, it is prevented that the grinding debris 50 blocks the top surface of the protective film 120 and is difficult to be fully illuminated by the specific light source, ensuring that the protective film 120 can be smoothly removed during the film tearing process.
[0073] In one example, the cleaning of the protective film 120 may include a scrubbing step, specifically: spraying a cleaning liquid onto the protective film 120 and scrubbing with a cleaning brush 61. Exemplarily, the cleaning liquid may be sprayed by the third nozzle 62, and the cleaning liquid may be sprayed onto the cleaning brush 61, so that the cleaning brush 61 can not only be scrubbed based on the cleaning liquid, but also the contaminants attached to the cleaning brush 61 can be rinsed in real time. The cleaning brush 61 used may be a ring-shaped brush that matches the shape of the edge area of the substrate 100; or, the brush head of the cleaning brush 61 may also be a small-sized strip brush head.
[0074] In this embodiment, the third nozzle 62 and the cleaning brush 61 can move synchronously. Specifically, during the cleaning process, the third nozzle 62 and the cleaning brush 61 can move synchronously from the inside to the outside of the substrate to perform brushing. Fig.12 As shown, the third nozzle 62 and the cleaning brush 61 are arranged along Fig.12 The cleaning agent 50 moves along the path indicated by the dotted line in the figure to sequentially clean the top surface of the protective film 120 to the sidewall of the protective film 120 to fully remove the grinding debris 50 adhered to the protective film 120.
[0075] It should be noted that the top surface of the edge portion of the protective film 120 in this embodiment is relatively flat without a step structure, so that the grinding debris 50 on the top surface of the protective film 120 is easier to remove. At the same time, since the edge of the protective film 120 is a flat surface, it is also convenient for the cleaning liquid to be discharged from the inside to the outside. Figure 3 and Fig.11 As shown, Figure 3 The edge of the protective film 12 covers the dielectric layer 11 to form a step structure, and the corners of the steps are deposited ( Figure 3 The grinding debris 50 (shown in the dotted box in FIG. 1 ) is difficult to remove, and even if it is cleaned, the grinding debris 50 is still likely to remain at the step position; however Fig.11 The edge of the protective film 120 is smooth, and the cleaning brush 61 can easily remove the adhered grinding debris 50, and can also brush the side wall of the protective film 120, which is conducive to the efficient removal of the grinding debris 50.
[0076] In addition, Figure 7 In the example of FIG. 1 , the protective film 120 completely covers the edge region 100B of the substrate. At this time, the cleaning brush 61 can be used to sequentially clean the top surface of the protective film 120 to the side wall of the protective film 120 from the inner side of the substrate to the edge of the substrate. Fig. 9In the example, the protective film 120 covers a portion of the edge region 100B of the substrate, so that the end of the protective film 120 is away from the lateral opening of the gap below the substrate during grinding. At the same time, the eaves effect brought by the edge of the substrate can also effectively reduce the adhesion of grinding debris 50 to the side wall of the protective film 120, further improving the cleanliness of the protective film 120 and reducing the workload of cleaning the side wall of the protective film. In addition, the end of the protective film 120 is retracted, which also reduces the use of protective film materials, which is conducive to cost saving.
[0077] Then, step S500 is performed, and the protective film 120 is irradiated with a specific light source to reduce the viscosity of the protective film 120 on the substrate 100, and the protective film 120 is removed. In a specific example, the protective film 120 is, for example, a UV film, and UV light can be used to irradiate the protective film to reduce the viscosity of the protective film 120. In this embodiment, by cleaning the protective film 120, the grinding debris on the protective film 120 is fully removed, so that the edge of the protective film 120 can also be fully irradiated by the light source, the viscosity can be effectively reduced, and it is easy to be removed from the substrate 100, thereby effectively improving the problem of the protective film 120 being difficult to remove and causing fragments.
[0078] It should be noted that, although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still belongs to the scope of protection of the technical solution of the present invention.
[0079] It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third", etc. in the specification are only used to distinguish the various components, elements, steps, etc. in the specification, rather than to represent the logical relationship or sequential relationship between the various components, elements, steps, etc. It should also be recognized that the terms described herein are only used to describe specific embodiments, rather than to limit the scope of the present invention. It must be noted that the singular forms "one" and "a kind" used herein and in the appended claims include plural references unless the context clearly indicates the opposite meaning. For example, a reference to "a step" or "a device" means a reference to one or more steps or devices, and may include secondary steps and secondary devices. All conjunctions used should be understood in the broadest sense. And, the word "or" should be understood to have the definition of a logical "or", rather than a logical "exclusive or" definition, unless the context clearly indicates the opposite meaning.
Claims
1. A method for thinning a substrate, characterized in that: include: A protective film is attached to the first surface of the substrate, wherein the top surface of the protective film located in the edge region of the substrate is flatter than the top surface of the protective film located in the inner region of the substrate; Placing the substrate on a grinding table with its first surface facing the grinding table, and performing a grinding process on the second surface of the substrate to reduce the thickness of the substrate; Cleaning at least the edge portion of the protective film to remove grinding debris on the protective film; as well as, The protective film is irradiated with a specific light source to reduce the viscosity of the protective film on the substrate, and then the protective film is removed.
2. The method for thinning a substrate as claimed in claim 1, characterized in that: The method of attaching a protective film on a first surface of a substrate comprises: forming a dielectric layer on the first surface of the substrate, and removing a portion of the dielectric layer covering an edge region of the substrate; and, A protective film is attached to the first surface of the substrate, and the edge of the protective film is attached to the edge area of the substrate so that the top surface of the protective film located in the edge area of the substrate is flatter than the top surface of the protective film located in the inner area of the substrate.
3. The method for thinning a substrate as claimed in claim 2, characterized in that: The method for preparing the dielectric layer comprises: Coating a photoresist layer on the first surface of the substrate; performing an edge cleaning process to remove a portion of the photoresist layer at an edge region of the substrate; and A photolithography process is performed to pattern the photoresist layer in the inner peripheral area of the substrate to form a capping pattern covering each chip area.
4. The method for thinning a substrate as claimed in claim 2, characterized in that: The substrate has multiple chip areas, the chip area inside the substrate is a valid chip area, the chip area at the edge of the substrate is an invalid chip area, the area of the invalid chip area constitutes the edge area of the substrate, the part of the dielectric layer covering the invalid chip area is removed, and the part of the protective film covering the edge area forms a concave ring structure.
5. The method for thinning a substrate as claimed in claim 1, characterized in that: The protective film is completely attached to the edge area of the substrate.
6. The method for thinning a substrate according to claim 1, wherein: The protective film covers a portion of the edge region of the substrate, so that the end of the protective film is retracted relative to the outer side wall of the substrate.
7. The method for thinning a substrate according to claim 1, wherein: The inward dimension of the end of the protective film relative to the outer side wall of the substrate is less than 3 mm.
8. The method for thinning a substrate as claimed in claim 1, characterized in that: The method of cleaning the edge portion of the protection film includes spraying a cleaning liquid onto a top surface and a side wall of the edge portion of the protection film using a nozzle, and brushing the cleaning liquid using a cleaning brush.
9. The method for thinning a substrate as claimed in claim 8, characterized in that: The nozzle and the cleaning brush are synchronously moved from the inner side to the outer side of the substrate to perform cleaning, so as to sequentially clean the top surface of the protective film and the side wall of the protective film.
10. The method for thinning a substrate according to claim 1, wherein: During the grinding process, the method further includes spraying a cleaning liquid to the periphery of the substrate to remove grinding debris accumulated on the periphery of the substrate.
11. The method for thinning a substrate according to claim 1, wherein: The protective film is a UV film. Before removing the protective film, the protective film is irradiated with a UV light source to reduce the viscosity of the protective film.