Semiconductor substrate, film pasting method thereof and chemical plating execution method

Abstract

The invention provides a semiconductor substrate, a film pasting method thereof and a method for executing chemical plating. According to the film pasting method, a semiconductor substrate is arranged in a step shape from an internal area to an edge ring area, a first protective film covers the table top of the lowest step, and meanwhile, a second protective film is further attached to the upper portion of the first protective film. Therefore, under the coverage of the second protective film, the risk that a chemical reagent permeates into the position below the first protective film can be further reduced, good protection on the internal area is achieved, and the product in the internal area is effectively prevented from being affected. And the second protective film is attached to the highest step of the edge ring region, so that the surface of the semiconductor substrate can be completely covered, and the edge of the substrate is prevented from being exposed and corroded by chemical reagents.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a semiconductor substrate, a film attaching method thereof, and a method for performing chemical plating. Background Art

[0002] Chemical plating is a new metal surface treatment technology that has replaced electroplating in many fields as an environmentally friendly surface treatment process. For example, in the field of new energy vehicles, automotive-grade IGBTs have high reliability requirements. To meet these high reliability requirements, the industry generally uses chemical plating to grow the surface metal of IGBTs (for example, Ni / Au or Ni / Pd / Au) to meet the requirements of automotive-grade IGBT interconnection.

[0003] Among them, chemical plating can be divided into single-sided plating and double-sided plating. For the single-sided plating process, a protective film needs to be attached to the other side of the wafer (for example, the back) to prevent the back of the wafer from contacting the chemical agent, and the protective film is removed after the chemical plating is completed. For example, Figure 1 As shown, before performing chemical plating on one side of the wafer 10, a Taiko thinning process is usually used to thin the other side of the wafer 10. The Taiko thinning process does not thin the entire surface of the wafer 10, but only thins the middle part of the wafer 10, thereby forming a thicker support ring at the edge of the wafer 10. The support ring is usually called a Taiko ring; then, a protective film 20 is attached to the surface of the wafer 10, and the protective film 20 is attached to the entire surface.

[0004] However, based on Figure 1 When applying protective film 20 using the illustrated lamination method, the Taiko ring protrudes from the center of the wafer, creating a step. This creates a slit 20a in protective film 20 at the location of the step. During the electroless plating process, the circulating chemical can easily seep from the edge of protective film 20 into slit 20a, exposing the wafer backside to the electroless plating solution and severely impacting product yield. Summary of the Invention

[0005] The object of the present invention is to provide a method for laminating a semiconductor substrate to solve the problem that the laminating method in the prior art is still prone to chemical reagent infiltration in subsequent processes, resulting in contact between the back side of the wafer and the chemical plating solution.

[0006] In this regard, the present invention provides a method for laminating a semiconductor substrate, comprising: providing a semiconductor substrate, wherein the semiconductor substrate further defines an edge ring area and an internal area surrounded by the edge ring area; wherein the surface of the edge ring area protrudes at least one step relative to the surface of the internal area, the surface of the internal area constitutes a first-level table, and the end of the first protective film extends to the step sidewall of the lowest step of the at least one step; attaching a first protective film on the surface of the semiconductor substrate, the first protective film being attached to the first-level table; and attaching at least one layer of second protective film on the surface of the semiconductor substrate, the second protective film being attached to at least the edge ring area, and the topmost second protective film being attached to the table of the highest step of the at least two steps.

[0007] Optionally, the outer morphology of the first protective film matches the inner morphology surrounded by the lowest step, and the end sidewall of the first protective film is made to fit the step sidewall of the lowest step in the at least one step.

[0008] Optionally, the surface of the edge ring area protrudes by at least two steps relative to the surface of the inner area, and the heights of the at least two steps gradually increase from the inner ring to the outer ring.

[0009] Optionally, only a second protective film is attached to the surface of the semiconductor substrate, and the second protective film is attached to the terraces of each step in the edge ring area.

[0010] Optionally, the thickness of the second protective film is smaller than the height of each step covered by the second protective film.

[0011] Optionally, the number of attached second protective films is consistent with the number of steps in the edge ring area, and each layer of the second protective film is attached to the mesa of each step in a one-to-one correspondence.

[0012] Optionally, the thickness of the second protective film attached to each lower step below the highest step is consistent with the height of the step directly facing the end thereof.

[0013] Optionally, the second protective film covers the edge ring area and also extends to the inner area to be attached to the first protective film, wherein the second protective film only extends to a portion of the inner area close to the edge ring area; or the second protective film completely covers the inner area.

[0014] Optionally, the viscosity of the second protective film is greater than the viscosity of the first protective film.

[0015] Optionally, the thickness of the first protective film is consistent with the height of the second-level table directly facing its end.

[0016] Another object of the present invention is to provide a semiconductor substrate with a protective film attached thereto, wherein the semiconductor substrate is defined with an edge ring area and an internal area surrounded by the edge ring area; wherein the surface of the edge ring area protrudes by at least one step relative to the surface of the internal area, the surface of the internal area constitutes a first-level table, and the end of the first protective film extends to the step sidewall of the lowest step among the at least one step; and, a first protective film and at least one layer of second protective film are attached to the semiconductor substrate, wherein the first protective film is attached to the surface of the internal area, the second protective film is attached to at least the edge ring area, and the topmost second protective film is attached to the table of the highest step among the at least one step.

[0017] Optionally, the outer morphology of the first protective film matches the inner morphology surrounded by the lowest step, and the end sidewall of the first protective film is made to fit the step sidewall of the lowest step in the at least one step.

[0018] Optionally, the surface of the edge ring area protrudes by at least two steps relative to the surface of the inner area, and the heights of the at least two steps gradually increase from the inner ring to the outer ring.

[0019] Optionally, only a second protective film is attached to the surface of the semiconductor substrate, and the second protective film is attached to the terraces of each step in the edge ring area, wherein the thickness of the second protective film is smaller than the step height of each step it covers.

[0020] Optionally, the number of attached second protective films is consistent with the number of steps in the edge ring area, and each layer of the second protective film is attached to the table of each step one by one, wherein the film thickness of the second protective film attached to each lower step below the highest step is consistent with the height of the step facing its end.

[0021] Optionally, the second protective film covers the edge ring area and also extends to the inner area to be attached to the first protective film, wherein the second protective film only extends to a portion of the inner area close to the edge ring area; or the second protective film completely covers the inner area.

[0022] Optionally, the thickness of the first protective film is consistent with the height of the second-level table that its end faces. Also, the viscosity of the second protective film may be greater than that of the first protective film.

[0023] Another object of the present invention is to provide a method for performing chemical plating, comprising: using the film-attaching method as described above to attach a protective film on the first surface of a semiconductor substrate; performing a chemical plating process to form chemically plated metal on the second surface of the substrate; and, after performing the chemical plating process, peeling off the second protective film and causing the first protective film to be removed.

[0024] The film-attaching method for semiconductor substrates provided by the present invention can better protect the semiconductor substrate and prevent chemical reagents in subsequent processes from penetrating into the internal area and affecting the product yield. Specifically, in the film-attaching method, a first protective film is used to cover the table of the lowest step (corresponding to the first-level table of the internal area). At this time, the first protective film is attached to the flat surface of the internal area, effectively improving the protection of the internal area, and a second protective film is also attached above the first protective film. The second protective film is attached to the highest step of the edge ring area so that the surface of the semiconductor substrate can be fully covered to prevent the edge of the substrate from being exposed and corroded by chemical reagents; and, by attaching the first protective film, the height difference between the internal area and the edge ring area can be compensated, improving the problem of gaps in the protective film at the boundary position of the internal area due to the step difference. At the same time, under the coverage of the second protective film, the thread of the chemical plating solution penetrating into the internal area is increased, making it more difficult for the chemical reagent to penetrate below the first protective film, effectively preventing the products in the internal area from being affected.

[0025] In practical applications, the film lamination parameters can be set in the film lamination equipment so that the first protective film can be aligned and attached to the surface of the inner area (i.e., the first level table), eliminating the gap between the first protective film and the step directly opposite the end thereof, blocking the infiltration path of the chemical plating solution, and further preventing the chemical plating solution from penetrating into the inner area. In addition, it should be recognized that even if a small gap exists between the end of the first protective film and the step directly opposite it, the second protective film above it can cover the gap, making it difficult for chemical reagents to penetrate into the gap.

[0026] In addition, when the edge ring area protrudes with at least two steps and only a second protective film is attached to the surface of the semiconductor substrate, even if the upper second protective film has a slit at the corner of the step, the chemical reagent may penetrate into the slit. However, since the first protective film is also attached under the second protective film, the first protective film has a high degree of adhesion on the flat first-level table surface, making it difficult for the chemical reagent in the slit to penetrate under the first protective film. Good protection of the internal area can still be achieved, effectively preventing the products in the internal area from being affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The figure is a schematic structural diagram of an existing semiconductor substrate with a protective film attached.

[0028] Figure 2 FIG. 4 is a flow chart of a method for laminating a semiconductor substrate according to an embodiment of the present invention.

[0029] Figure 3-Figure 5 Schematic diagram of the structure of the semiconductor substrate during the process of attaching a protective film in the first embodiment of the present invention.

[0030] Figure 6 Schematic diagram of the structure of the semiconductor substrate after a protective film is attached thereto in the second embodiment of the present invention.

[0031] Figure 7 and Figure 8 Schematic diagrams of two structures of the semiconductor substrate after a protective film is attached thereto in the third embodiment of the present invention.

[0032] Figure 9 Schematic diagram of the structure of the semiconductor substrate after a protective film is attached thereto in the fourth embodiment of the present invention.

[0033] The accompanying drawings are numerals as follows:

[0034] 10-wafer;

[0035] 20-protective film;

[0036] 20a-gap;

[0037] 100-semiconductor substrate;

[0038] 100A-marginal ring area;

[0039] 100B-Interior area;

[0040] 110-first level countertop;

[0041] 120-second level countertop;

[0042] 130-third level countertop;

[0043] 210-first protective film;

[0044] 220 - second protective film. DETAILED DESCRIPTION

[0045] The core idea of ​​the present invention is to provide a film-laminating method for semiconductor substrates, which can effectively reduce the further diffusion of chemical reagents that penetrate into the slits into the inner area of ​​the substrate, thereby avoiding affecting the products in the inner area; it can even avoid the formation of slits under the protective film, better block chemical reagents, and improve the protection of the semiconductor substrate.

[0046] For details, please refer to Figure 2As shown, a method for laminating a semiconductor substrate in one embodiment of the present invention includes the following steps.

[0047] Step S100, providing a semiconductor substrate, wherein the semiconductor substrate is defined with an edge ring area and an inner area surrounded by the edge ring area; wherein the surface of the edge ring area protrudes at least one step relative to the surface of the inner area, and the surface of the inner area constitutes a first-level terrace.

[0048] In step S200 , a first protective film is attached to the surface of the semiconductor substrate, wherein the first protective film is attached to the first mesa, and an end of the first protective film extends to a sidewall of the lowest step of the at least one step.

[0049] In step S300 , at least one second protective film is attached to the surface of the semiconductor substrate, wherein the second protective film is attached to at least the edge ring area, and the topmost second protective film is attached to the highest step of the at least one step.

[0050] That is, in the film-sticking method provided by the present invention, the surface of the edge ring area is made to protrude by at least one step relative to the surface of the internal area, and the first protective film is attached to the flat first-level table, thereby improving the fit of the first protective film on the surface of the substrate and ensuring the protection strength of the internal area. Moreover, when the first protective film is attached, the height difference between the internal area and the edge ring area can be compensated, thereby improving the problem of gaps in the boundary position of the protective film in the internal area due to the step difference. In addition, the second protective film is used to cover the steps of the edge ring area, thereby avoiding the edge ring area from being exposed and increasing the difficulty of chemical reagent penetration. At the same time, the second protective film can also be attached to at least the end of the first protective film to prevent chemical reagents from penetrating from the end of the first protective film and affecting the product in the internal area. Moreover, when the film is torn off, the second protective film can also be driven by the first protective film to be removed at the same time, thereby simplifying the film-tearing process.

[0051] The semiconductor substrate and its film-mounting method, as well as the method for performing chemical plating proposed in the present invention are further described in detail below with reference to specific embodiments. The advantages and features of the present invention will become clearer based on the following description. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in illustrating 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 would now be below that element.

[0052] <Example 1>

[0053] In step S100, refer to Figure 3 As shown, a semiconductor substrate 100 is provided. The semiconductor substrate 100 may include, for example, a wafer. The semiconductor substrate 100 has a first surface and a second surface facing each other, one of which is a back surface and the other is a front surface. In this embodiment, the front surface of the semiconductor substrate 100 is used as the surface to be electrolessly plated, and the back surface is used as the surface to be attached with a protective film.

[0054] Furthermore, the semiconductor substrate 100 defines an edge ring region 100A and an inner region 100B surrounded by the edge ring region. Semiconductor devices, such as power devices, may be formed in the inner region 100B. The semiconductor devices may further include IGBT devices, for example. Furthermore, the surface of the edge ring region 100A (specifically, the surface to which the protective film is to be attached, such as the second surface) protrudes by at least one step relative to the surface of the inner region 100B. In a specific example, the surface of the edge ring region 100A may protrude by at least two steps, and the step heights of the at least two steps within the edge ring region 100A gradually increase from the inner ring to the outer ring. It can be considered that the surface of the inner region 100B constitutes a first-level mesa, with each step of the edge ring region 100A gradually increasing relative to the first-level mesa. Therefore, the outermost ring of the edge ring region 100A corresponds to the highest step, while the inner region 100B corresponds to the lowest step. In this embodiment, the surface of the edge ring area 100A is two steps higher than the surface of the inner area 100B. Therefore, the surface of the inner area 100B can constitute a first-level mesa 110, and a second-level mesa 120 and a third-level mesa 130 are formed in the edge ring area 100A.

[0055] The method for making the surface of the edge ring region 100A protrude at least two steps relative to the surface of the inner region 100B includes, for example: thinning the surface of the semiconductor substrate 100, with the inner region 100B being thinned to the greatest thickness, so that the surface of the inner region 100B is recessed to form a first-level mesa with the lowest mesa; and gradually reducing the thinning thickness of multiple ring regions extending outward from the inner region 100B, so that the surface of the edge ring region 100A forms at least two steps that gradually increase in size from the inner ring to the outer ring.

[0056] In a specific example, the method for forming at least two steps may include: performing at least two thinning processes (e.g., Taiko thinning processes) on the surface of the semiconductor substrate 100, wherein the thinning areas covered by the at least two thinning processes gradually shrink toward the center of the substrate, thereby forming at least two steps that gradually decrease from an outer ring to an inner ring, and the mesa range of the lowest step (corresponding to the thinning range corresponding to the last thinning) at least includes the inner area 100B. The thinning process may, for example, include a mechanical grinding process, i.e., grinding the surface of the semiconductor substrate 100 using a mechanical grinding process to achieve the thinning process.

[0057] For example, the process of forming a two-step step includes: performing a first thinning process, wherein the thinning range of the first thinning process does not cover the outermost ring of the edge ring area 100A, so that the outermost ring of the edge ring area 100A is not thinned in the first thinning process, thereby protruding after the first thinning process to form the highest step with the highest mesa surface; then, performing a second thinning process, wherein the thinning range of the second thinning process is retracted toward the center of the substrate relative to the thinning range of the first thinning process, so as to form a step of a second height within the edge ring area 100A and further sink the surface of the inner region 100B after the thinning process to form the lowest mesa surface. That is, in this embodiment, the surface of the inner region 100B is further sunken one step relative to the lowest mesa surface in the edge ring area 100A, thereby forming the lowest mesa surface (i.e., the first-level mesa surface).

[0058] In step S200, refer to Figure 4 As shown, a first protective film 210 is attached to the surface of the semiconductor substrate 100, and the first protective film 210 is attached to the first-level mesa 110. That is, the first protective film 210 is attached to the flat mesa, so that the first protective film 210 can more completely adhere to the surface of the inner area 100B.

[0059] Furthermore, the end of the first protective film 210 extends to the sidewall of the lowest step in at least one step (i.e., the sidewall of the step directly opposite the end of the first protective film 210), so that the outer morphology of the first protective film 210 matches the inner morphology of the lowest step. In other words, the first protective film 210 is laminated with its lamination area as the first-level table surface, and the end sidewall of the first protective film is laminated to the sidewall of the step directly opposite the end as the lamination target. This allows the end sidewall of the first protective film 210 to approach or laminate to the sidewall of the step directly opposite the end, thereby pre-laminating and eliminating the narrow gap space that is prone to occur in traditional technologies. Therefore, the problem of narrow gaps caused by covering the step is eliminated, effectively reducing the risk of chemical reagent penetration in subsequent processes.

[0060] The thickness of the first protective film 210 is not limited and can be greater than or less than the height of the step directly facing the end of the first protective film 210 (i.e., the height of the second mesa 120). Alternatively, the thickness of the first protective film 210 can be made consistent with the height of the step directly facing the end of the first protective film, that is, the thickness of the first protective film 210 is consistent with the height of the second mesa 120. In this embodiment, the thickness of the first protective film 210 is made consistent with the height of the second mesa 120 to reduce the height difference between the surface of the first protective film 210 and the second mesa 120, which is conducive to improving the adhesion of the subsequent second protective film.

[0061] In step S300, refer to Figure 5 As shown, at least one layer of second protective film 220 is applied to the surface of semiconductor substrate 100. This second protective film 220 is applied to at least the edge ring area 100A, with the topmost second protective film 220 applied to the highest step of the at least one step. Because the topmost second protective film 220 is applied to the highest mesa, each mesa in edge ring area 100A is covered by the protective film, preventing corrosion from chemical exposure during subsequent manufacturing processes.

[0062] In a specific example, only a layer of second protective film 220 is attached to the surface of the semiconductor substrate 100. The second protective film 220 constitutes the topmost second protective film 220, which is attached to the table of each step in the edge ring area 100A. The second protective film 220 in this embodiment is attached to the second-level table 120 and the third-level table 130.

[0063] Continue to refer Figure 5 As shown, in this embodiment, the second protective film 220 is completely adhered to the inner region 100B and the edge ring region 100A. Accordingly, the second protective film 220 is simultaneously adhered to the second-level mesa 120 and the third-level mesa 130, which easily creates a slit at the step difference. However, it should be noted that although the second protective film 220 creates a slit at the location covering the step difference, the first protective film 210 is also adhered to the bottom of the second protective film 220. The first protective film 210 effectively covers the inner region 100B of the substrate and allows the end of the first protective film 210 to adhere to the sidewall of the step opposite the end, thereby pre-fabricating and eliminating the slit space that is prone to occur in conventional technologies. Therefore, even if chemical reagents penetrate into the slits, it is difficult for the chemical reagents to further penetrate under the first protective film 210, thereby completely protecting the inner region 100B from being affected.

[0064] Furthermore, the thickness of the second protective film 220 can be smaller than the height of each step it covers. By using a second protective film 220 with a smaller thickness, the second protective film 220 can be more closely fitted to each step and the size of the slits formed at the step differences can be reduced.

[0065] Furthermore, the viscosity of the second protective film 220 can be greater than that of the first protective film 210. This facilitates the subsequent removal of the first protective film 210 when the second protective film 220 is peeled off, without requiring multiple peeling processes, thereby simplifying the process.

[0066] <Example 2>

[0067] The difference from the first embodiment is that the number of second protection films formed on the semiconductor substrate in this embodiment is consistent with the number of steps in the edge ring area, and each second protection film is adhered to the corresponding mesa one by one.

[0068] Figure 6 FIG. 1 is a schematic diagram of the structure after the second protective film is attached in the second embodiment of the present invention. Figure 6 As shown, in this example, taking the two steps formed in the edge ring area 100A as an example, two layers of second protective film 220 are formed accordingly, and each layer of second protective film 220 is attached to a corresponding mesa one by one, that is, the two layers of second protective film 220 are attached to the second mesa and the third mesa respectively. Therefore, the film attachment method of this embodiment can prevent the second protective film 220 from being attached to steps of different heights at the same time, thereby preventing the second protective film 220 from forming cracks at the step difference, further improving the barrier effect against chemical reagents.

[0069] In a specific example, the thickness of each second protective film 220 can be made consistent with the height of the step directly facing its end. This reduces the height difference between the surface of the second protective film 220 and the step directly facing its end, ensures the flatness of the step directly facing the surface of the second protective film 220, and improves the adhesion of the subsequently attached second protective film 220 to the surface. In this embodiment, two layers of second protective film 220 are formed: the thickness of the lower second protective film 220 is consistent with the height of the second-level mesa 120, and the thickness of the upper second protective film 220 is consistent with the height of the third-level mesa 130.

[0070] <Example 3>

[0071] Different from the above embodiment, the second protective film in this embodiment covers the edge ring area and only extends to the part of the inner area close to the edge ring area, but does not completely cover the entire inner area, thereby effectively saving the amount of protective film and saving costs.

[0072] Figure 7 and Figure 8 Schematic diagrams of two structures after the second protective film is attached in the third embodiment of the present invention, as shown in FIG. Figure 7 and Figure 8 As shown, the second protective film 220 does not completely cover the entire substrate surface, but only covers the edge ring area 100A and the outer ring area outside the inner area 100B of the semiconductor substrate 100. Because the second protective film 220 is still attached to the first protective film 210, it can not only keep the ends of the first protective film 210 covered, but also prevent the chemical reagent from penetrating through the ends of the first protective film 210. Moreover, when the second protective film 220 is peeled off, it can still drive the removal of the first protective film 210.

[0073] Furthermore, the dimension D of the second protective film 220 attached to the first protective film 210 may be greater than or equal to 5 mm, for example, to ensure that the second protective film 220 can completely cover the end of the first protective film 210, and to ensure that there is sufficiently large adhesion between the second protective film 220 and the first protective film 210, so that in the subsequent film tearing process, the first protective film 210 can be removed based on the high-strength adhesion when peeling off the second protective film 220.

[0074] in, Figure 7 In the illustrated example, only one layer of second protective film 220 is applied. This second protective film 220 covers each mesa within edge ring area 100A and extends to the edge of inner area 100B, so that the end of second protective film 220 is in contact with first protective film 210. In this example, the thickness of second protective film 220 is less than the height of each step it covers, thereby improving the adhesion to each step and reducing the gaps caused by the step differences.

[0075] as well as, Figure 8 In the example shown, multiple layers of second protective film 220 are applied, one-to-one, to each table surface. Furthermore, the dimensions of the multiple layers of second protective film 220 extending into the interior region are uniform; alternatively, the dimensions of the upper layer of second protective film 220 in the interior region 100B can be smaller than the dimensions of the lower layer of second protective film 220 in the interior region 100B.

[0076] <Example 4>

[0077] Different from the above embodiment, the edge ring region of the semiconductor substrate in this embodiment protrudes only one step relative to the surface of the inner region.

[0078] Figure 9 This is a schematic diagram of the structure after the protective film is attached in the fourth embodiment of the present invention. Figure 9As shown, the edge ring area 100A protrudes only one step relative to the surface of the inner area 100B. The first protective film 210 is attached to the surface of the inner area 100B (i.e., the first level table), and the second protective film 220 is attached to the first protective film 210 and the table of the edge ring area 100A. The second protective film 220 can only be attached to the portion of the first protective film 210 close to the edge ring area 100A (for example, the width of the second protective film 220 attached to the first protective film 210 can be no less than 5mm); or the second protective film 220 can completely cover the first protective film 210, for example Figure 9 shown.

[0079] Furthermore, the thickness of the first protective film 210 can be the same as the step height of the edge ring area 100A, so that after the first protective film 210 is attached, the table of the edge ring area 100A and the top surface of the first protective film layer 210 appear as a flat surface as a whole, thereby improving the flatness of the attachment of the second protective film 220.

[0080] In this embodiment, a thinning process (e.g., a Taiko thinning process) may be performed on the surface of the semiconductor substrate 100. The thinning range of the thinning process does not cover the edge ring area 100A, so that the edge ring area 100A is not thinned during the thinning process. The surface of the inner region 100B after the thinning process is further sunken to form a lowest mesa, and the edge ring area 100A is raised to form a step. The thinning process may include, for example, a mechanical grinding process, that is, grinding the surface of the semiconductor substrate 100 using a mechanical grinding process to achieve the thinning process.

[0081] As described above, the first protective film 210 is attached to the flat surface of the internal area 100B, and the end side wall of the first protective film 210 can be adhered to the step side wall opposite to it, thereby eliminating the narrow space that is prone to appear in traditional technology in advance, and achieving high-strength protection of the internal area 100B. At the same time, the second protective film 220 can further cover the end of the first protective film 210, reducing the risk of chemical reagents penetrating into the internal area 100B through the end of the first protective film 210.

[0082] Based on the above-mentioned film attaching method, this embodiment also provides a semiconductor substrate with a protective film attached, which can be specifically combined with Figure 5-Figure 9 As shown, the semiconductor substrate 100 is defined with an edge ring region 100A and an inner region 100B surrounded by the edge ring region 100A; wherein the surface of the edge ring region 100A protrudes at least one step relative to the surface of the inner region 100B, and the surface of the inner region 100B forms a first-level terrace. In the case where the surface of the edge ring region 100A protrudes at least two steps relative to the surface of the inner region 100B (e.g. Figure 5-Figure 8As shown in FIG. 1 , the terrace heights of at least two steps in the edge ring area 100A increase gradually from the inner ring to the outer ring.

[0083] Furthermore, a first protective film 210 and at least one second protective film 220 are attached to the semiconductor substrate 100. The first protective film 210 is attached to the first-level mesa (i.e., the first protective film 210 is attached to the surface of the inner region 100B), and the end of the first protective film 210 extends to the sidewall of the lowest step within the edge ring region 100A, so that the outer morphology of the first protective film 210 matches the inner morphology surrounded by the lowest step. That is, the end sidewall of the first protective film 210 approaches or adheres to the sidewall of the step directly opposite its end, thereby pre-fabricating and eliminating the narrow space that is prone to occur in traditional technology. Furthermore, the second protective film 220 is attached to at least the edge ring region 100A, and the top layer of the second protective film 220 is attached to the mesa of the highest step in the edge ring region 100A.

[0084] For example, in Figure 5 and Figure 7 In the example shown, only a second protective film 220 is attached to the semiconductor substrate 100. This second protective film 220 covers the terraces of each step within the edge ring region 100A. Therefore, the second protective film 220 can be made thinner to improve adhesion to each step. Specifically, the thickness of the second protective film 220 can be smaller than the height of each step it covers.

[0085] And, in Figure 6 and Figure 8 In the example, the number of second protective films 220 attached to the semiconductor substrate 100 is consistent with the number of steps within the edge ring region 100A, so that each second protective film 220 is attached to each level of the mesa in a one-to-one correspondence. In this example, the thickness of the second protective film 220 can be made consistent with the height of the step directly facing its end. This ensures that the surface of the currently attached second protective film 220 has a higher flatness than the mesa directly facing its end, providing a flat surface for subsequent second protective films 220 to attach.

[0086] In addition, Figure 9 In the example, the edge ring area 100A only protrudes with one step, and in this case, only one layer of second protection film 220 needs to be attached. The second protection film 220 is attached to the first protection film 210 and the table surface of the edge ring area 100A.

[0087] Furthermore, the second protective film 220 covers the edge ring area 100A and extends to the inner area 100B to be attached to the first protective film 210, wherein the viscosity of the second protective film 220 can be made greater than the viscosity of the first protective film 210, so that when the second protective film 220 is peeled off, the first protective film 210 can be removed due to the high-strength adhesive force. Figure 5 、 Figure 6 and Figure 9 In the example of FIG, the second protective film 220 completely covers the inner area 100B; and Figure 7 and Figure 8 In the example, the second protective film 220 only extends to the portion of the inner region 100B close to the edge ring region 100A, so that the second protective film 220 is only attached to the end of the first protective film 210, thereby reducing the amount of protective film used and lowering costs.

[0088] As described above, the film lamination method for semiconductor substrates provided in this embodiment is beneficial for preventing chemical reagents from penetrating during subsequent processes. For example, during chemical plating, the risk of plating solution penetrating into internal areas and affecting the product can be reduced.

[0089] Specifically, the method for performing chemical plating provided in this embodiment includes: attaching a protective film on the first surface (for example, the back surface) of the semiconductor substrate using the method described above; then, performing a chemical plating process to form chemically plated metal on the second surface (for example, the front surface) of the semiconductor substrate, and during the process of performing chemical plating, the first surface of the semiconductor substrate can be covered by the protective film to avoid being affected by the chemical plating.

[0090] Specific combination Figure 5-Figure 9 As shown, in this embodiment, the edge ring area of ​​the semiconductor substrate 100 is arranged in a stepped shape, and the first protective film 210 covers the table of the lowest step (corresponding to the surface of the inner area 100B), and a second protective film 220 is attached above the first protective film 210, and at least the topmost second protective film 220 is attached to the table of the highest step of the edge ring area 100A, so that the first surface of the semiconductor substrate 100 can be fully covered to prevent the edge ring area of ​​the first surface of the substrate from being exposed and corroded by chemical reagents. At the same time, under the coverage of the second protective film 220, the risk of chemical reagents penetrating to the bottom of the first protective film 210 can be further reduced. Specifically, the first protective film 210 is attached under the second protective film 220, thereby compensating for the height difference between the inner area 100B and the edge ring area 100A, and alleviating the problem of gaps in the protective film at the boundary position of the inner area 100B due to the step difference; at the same time, the second protective film 220 can cover the end of the first protective film 210, increasing the difficulty of chemical reagents penetrating through the end of the first protective film 210, and effectively preventing the products in the inner area from being affected.

[0091] Furthermore, if the edge ring area 100A protrudes with at least two steps, the protruding steps can be used to further prevent chemicals from penetrating from the end of the first protective film 210 into the inner area 100B. It should also be understood that even if the upper second protective film 220 has a slit at the corner of the step, chemicals may penetrate into the slit. However, because the first protective film 210 is attached below the second protective film 220, the chemicals in the slit are unlikely to penetrate beneath the first protective film 210. This effectively protects the inner area 100B and effectively prevents the products in the inner area 100B from being affected.

[0092] In a further embodiment, after the electroless plating process is performed, the second protective film 220 is peeled off, thereby causing the first protective film to be removed. Specifically, the second protective film 220 adheres to the edge ring area 100A and also extends to the inner area 100B, thereby at least partially adhering to the first protective film 210. The viscosity of the second protective film 220 is greater than that of the first protective film 210. Therefore, when the second protective film 220 is peeled off, the strong adhesion of the second protective film 220 to the first protective film 210 causes the first protective film 210 to be removed, thereby achieving the complete peeling of the protective films.

[0093] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the equipment disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part description. Although the present invention has been disclosed as above with preferred embodiments, the above embodiments are not intended to limit the present invention. For any technician familiar with the field, 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 modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

[0094] It should also be understood that the terms described herein are used only to describe particular embodiments and are not intended to limit the scope of the present invention. It should be noted that the singular forms "a" and "an" as used herein and in the appended claims include plural references unless the context clearly indicates otherwise. For example, reference to "a step" or "a device" means 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. Also, the word "or" should be understood to have the definition of a logical "or" rather than a logical "exclusive or" unless the context clearly indicates otherwise.

Claims

1. A method for attaching a film to a semiconductor substrate, characterized in that: include: A semiconductor substrate is provided, wherein an edge ring region and an inner region surrounded by the edge ring region are defined in the semiconductor substrate; wherein a surface of the edge ring region protrudes at least one step relative to a surface of the inner region, and the surface of the inner region constitutes a first-level terrace; A first protective film is attached to the surface of the semiconductor substrate, the first protective film is attached to the first stage mesa, and an end of the first protective film extends to a step side wall of the lowest step of the at least one step; and At least one second protective film is attached to the surface of the semiconductor substrate, the second protective film is at least attached to the edge ring area, and the topmost second protective film is attached to the terrace of the highest step of the at least one step.

2. The method for attaching a film to a semiconductor substrate according to claim 1, wherein: The outer morphology of the first protective film matches the inner morphology surrounded by the lowest step, and the end side wall of the first protective film is made to fit the step side wall of the lowest step in the at least one step.

3. The method for attaching a film to a semiconductor substrate according to claim 1, wherein: The surface of the edge ring area protrudes at least two steps relative to the surface of the inner area, and the table heights of the at least two steps gradually increase from the inner ring to the outer ring.

4. The method for attaching a film to a semiconductor substrate according to claim 3, wherein: Only one layer of second protective film is attached to the surface of the semiconductor substrate, and the second protective film is attached to the terraces of each step in the edge ring area.

5. The method for attaching a film to a semiconductor substrate according to claim 4, wherein: The thickness of the second protection film is smaller than the height of each step covered by the second protection film.

6. The method for attaching a film to a semiconductor substrate according to claim 3, wherein: The number of the attached second protective films is consistent with the number of steps in the edge ring area, and each layer of the second protective film is attached to the table surface of each step in a one-to-one correspondence.

7. The method for attaching a film to a semiconductor substrate according to claim 6, wherein: The thickness of the second protective film attached to each lower step below the highest step is consistent with the height of the step directly facing the end thereof.

8. The method for attaching a film to a semiconductor substrate according to any one of claims 1 to 7, characterized in that: The second protective film covers the edge ring area and also extends to the inner area to be attached to the first protective film; The second protective film only extends to a portion of the inner region close to the edge ring region; or the second protective film completely covers the inner region.

9. The method for attaching a film to a semiconductor substrate according to claim 1, wherein: The viscosity of the second protective film is greater than the viscosity of the first protective film.

10. The method for attaching a film to a semiconductor substrate according to claim 1, wherein: The thickness of the first protective film is consistent with the height of the second-level table surface that the end portion of the first protective film faces.

11. A semiconductor substrate with a protective film attached thereto, characterized in that: The semiconductor substrate is defined with an edge ring area and an inner area surrounded by the edge ring area; wherein the surface of the edge ring area protrudes at least one step relative to the surface of the inner area, and the surface of the inner area constitutes a first-level terrace; and A first protective film and at least one layer of a second protective film are attached to the semiconductor substrate, wherein the first protective film is attached to the first-level table top, and the end of the first protective film extends to the step side wall of the lowest step among the at least one step; the second protective film is at least attached to the edge ring area, and the topmost second protective film is attached to the table top of the highest step among the at least one step.

12. The semiconductor substrate with a protective film attached thereto according to claim 11, wherein: The outer morphology of the first protective film matches the inner morphology surrounded by the lowest step, and the end side wall of the first protective film is made to fit the step side wall of the lowest step in the at least one step.

13. The semiconductor substrate with a protective film attached thereto according to claim 11, wherein: The surface of the edge ring area protrudes at least two steps relative to the surface of the inner area, and the table heights of the at least two steps gradually increase from the inner ring to the outer ring.

14. The semiconductor substrate with a protective film attached thereto according to claim 13, wherein: Only one second protective film is attached to the surface of the semiconductor substrate, and the second protective film is attached to the terraces of each step in the edge ring area, wherein the thickness of the second protective film is smaller than the step height of each step covered by the second protective film.

15. The semiconductor substrate with a protective film attached thereto according to claim 13, wherein: The number of attached second protective films is consistent with the number of steps in the edge ring area, and each layer of the second protective film is attached to the table surface of each step one by one, wherein the film thickness of the second protective film attached to each lower step under the highest step is consistent with the step height directly facing its end.

16. The semiconductor substrate with a protective film attached thereto according to any one of claims 11 to 15, characterized in that: The second protective film covers the edge ring area and also extends to the inner area to be attached to the first protective film; The second protective film only extends to a portion of the inner region close to the edge ring region; or the second protective film completely covers the inner region.

17. The semiconductor substrate with a protective film attached thereto according to claim 11, wherein: The thickness of the first protective film is consistent with the height of the second-level table surface that the end portion of the first protective film faces.

18. The semiconductor substrate with a protective film attached thereto according to claim 11, wherein: The viscosity of the second protective film is greater than the viscosity of the first protective film.

19. A method for performing chemical plating, characterized in that: include: Adopting the film attaching method as described in any one of claims 1 to 10, attaching a protective film on the first surface of the semiconductor substrate; performing an electroless plating process to form an electroless plated metal on the second surface of the substrate; as well as, After the chemical plating process is completed, the second protective film is peeled off, and the first protective film is removed as a result.

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