Method of forming a semiconductor structure
By forming a stress film layer structure on the non-functional surface of the wafer, combined with laser annealing and ion implantation technology, the wafer warpage problem was solved, the risk of warpage deformation to subsequent processes was reduced, and the wafer warpage recovery efficiency was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SEMICON MFG INT (BEIJING) CORP
- Filing Date
- 2023-08-15
- Publication Date
- 2026-07-21
AI Technical Summary
In semiconductor manufacturing, wafer warping can prevent subsequent process steps from proceeding normally, affecting the quality and yield of chip products.
By forming a stress film layer structure on the non-functional surface of the wafer, laser annealing is performed, the warpage is detected, and ion implantation is performed according to the warpage until the warpage returns to normal. The energy, dose, and type of ion implantation are adjusted to flexibly adjust the stress.
It effectively reduces the risk of wafer warpage to subsequent processes, is easy to operate and low in cost, and can flexibly adjust the stress according to the degree of warpage, thereby improving the wafer warpage recovery efficiency.
Smart Images
Figure CN119495583B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing, and more particularly to a method for forming a semiconductor structure. Background Technology
[0002] During semiconductor manufacturing, wafers undergo deformation as they pass through stages such as stress engineering and annealing. This deformation typically results in a downward-curving "saddle shape" or an upward-curving "bowl shape." The degree of wafer warpage is a crucial parameter in integrated circuit manufacturing, determining whether subsequent process steps can proceed correctly and impacting the quality and yield of the final chip product.
[0003] Therefore, it is particularly important to effectively and quickly resolve the problem of wafer warpage. Summary of the Invention
[0004] The technical problem solved by this invention is to provide a method for forming a semiconductor structure to improve wafer warpage.
[0005] To address the aforementioned technical problems, the present invention provides a method for forming a semiconductor structure, comprising: providing a wafer, the wafer including functional and non-functional surfaces; forming a first stress film layer structure on the non-functional surface; performing laser annealing on the wafer; after performing laser annealing on the wafer, acquiring the wafer warpage and determining whether the wafer has warped; if the wafer warps, acquiring the wafer warpage condition; and based on the wafer warpage condition, performing ion implantation on the non-functional surface of the wafer until the wafer warpage returns to a normal state.
[0006] Optionally, the warpage of the wafer includes: warpage direction, which includes upward warpage and downward warpage. The upward warpage includes: the curvature center of the warpage surface of the wafer is located on one side of the functional surface; the downward warpage includes: the curvature center of the warpage surface of the wafer is located on one side of the non-functional surface.
[0007] Optionally, based on the warpage of the wafer, ion implantation is performed on the non-functional surface of the wafer, including: if the warpage direction of the wafer is upward, then ion implantation of a first ion is performed on the non-functional surface of the wafer; if the warpage direction of the wafer is downward, then ion implantation of a second ion is performed on the non-functional surface of the wafer; wherein the molar mass of the first ion is greater than the molar mass of the second ion.
[0008] Optionally, the molar mass of the first ion is greater than 10, and the molar mass of the second ion is less than 10.
[0009] Optionally, the wafer warpage may also include the wafer curvature.
[0010] Optionally, before ion implantation of the non-functional surface of the wafer, the method further includes: performing a first thinning process on the first stress film layer structure when the curvature of the wafer is greater than a preset value range; and performing a second thinning process on the first stress film layer structure when the curvature of the wafer is less than a preset value range.
[0011] Optionally, the preset value range is: curvature less than 100.
[0012] Optionally, the thickness of the first thinning process is greater than the thickness of the second thinning process.
[0013] Optionally, the warping direction of the wafer is upward; after performing a first thinning treatment on the first stress film layer structure, ion implantation is performed on the non-functional surface of the wafer, including: obtaining a continuous warped surface, the continuous warped surface including a first region and a second region located on both sides of the first region, the curvature of the first region being greater than the curvature of the second region; performing ion implantation of a first ion on the non-functional surface of the first region, and performing ion implantation of a second ion on the non-functional surface of the second region.
[0014] Optionally, the warping direction of the wafer is downward warping; after performing a first thinning treatment on the first stress film layer structure, ion implantation is performed on the non-functional surface of the wafer, including: obtaining a continuous warped surface, the continuous warped surface including a first region and a second region located on both sides of the first region, the curvature of the first region being greater than the curvature of the second region; performing second ion implantation on the non-functional surface of the first region, and performing first ion implantation on the non-functional surface of the second region.
[0015] Optionally, when the curvature of the wafer is greater than a preset value range, after performing a first thinning process on the first stress film layer structure and before performing ion implantation on the non-functional surface of the wafer, the method further includes: removing part of the remaining first stress film layer structure so that the remaining first stress film layer structure forms a patterned layer on the non-functional surface.
[0016] Optionally, the projected pattern of the graphical layer on the non-functional surface includes a circle or a square.
[0017] Optionally, the warpage direction of the wafer is upward warpage; after performing a second thinning treatment on the first stress film layer structure, ion implantation is performed on the non-functional surface of the wafer, including: obtaining a continuous warpage surface, the continuous warpage surface including a first region and a second region located on both sides of the first region, the curvature of the first region being greater than the curvature of the second region; performing ion implantation of a first ion on the non-functional surface of the first region; after performing ion implantation of the first ion on the non-functional surface of the first region, obtaining the degree of wafer warpage relief; if the degree of wafer warpage is relieved and the degree of wafer warpage is greater than a preset value range, performing ion implantation of a second ion on the non-functional surface of the second region.
[0018] Optionally, the warpage direction of the wafer is downward warpage; after performing a second thinning treatment on the first stress film layer structure, ion implantation is performed on the non-functional surface of the wafer, including: obtaining a continuous warpage surface, the continuous warpage surface including a first region and a second region located on both sides of the first region, the curvature of the first region being greater than the curvature of the second region; performing second ion implantation on the non-functional surface of the first region; after performing second ion implantation on the non-functional surface of the first region, obtaining the degree of wafer warpage relief; if the degree of wafer warpage is relieved and the degree of wafer warpage is greater than a preset value range, performing first ion implantation on the non-functional surface of the second region.
[0019] Optionally, the warping direction of the wafer is upward warping; after performing a second thinning treatment on the first stress film layer structure, ion implantation is performed on the non-functional surface of the wafer, including: obtaining a continuous warped surface, the continuous warped surface including a first region and a second region located on both sides of the first region, the curvature of the first region being greater than the curvature of the second region; and performing ion implantation of the first ion on the non-functional surface of the first region and the non-functional surface of the second region.
[0020] Optionally, the warping direction of the wafer is downward warping; after performing a second thinning treatment on the first stress film layer structure, ion implantation is performed on the non-functional surface of the wafer, including: obtaining a continuous warped surface, the continuous warped surface including a first region and a second region located on both sides of the first region, the curvature of the first region being greater than the curvature of the second region; and performing second ion implantation on the non-functional surface of the first region and the non-functional surface of the second region.
[0021] Optionally, after ion implantation of the non-functional surface of the wafer according to the wafer warpage, the process further includes: performing rapid thermal annealing on the wafer.
[0022] Optionally, the method for obtaining the warpage of the wafer and determining whether the wafer has warped includes: obtaining the warpage of the wafer; if the warpage is within a preset range, then determining that the wafer has not warped; if the warpage is greater than the preset range, then determining that the wafer has warped; the wafer warpage returning to a normal state includes: the wafer warpage meeting the preset range.
[0023] Optionally, while forming the first stress membrane layer structure on the non-functional surface, the method also includes forming a second stress membrane layer structure on the functional surface.
[0024] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:
[0025] The technical solution of this invention involves acquiring the wafer's warpage after laser annealing to determine if warping has occurred. Based on the warpage condition, ion implantation is performed on the non-functional surfaces of the wafer until the warpage returns to normal. This method only requires detecting the wafer's warpage on the existing equipment and selecting the appropriate solution based on the direction and degree of warpage, making it convenient and low-cost. Furthermore, the stress can be flexibly adjusted by modifying the ion implantation energy, dosage, and ion type according to the degree of warpage, thereby effectively and flexibly adjusting the wafer's warpage. In summary, this method effectively reduces the risks to subsequent processes caused by wafer warpage deformation. Attached Figure Description
[0026] Figure 1 This is a schematic flowchart of the semiconductor structure formation process in an embodiment of the present invention;
[0027] Figures 2 to 5 This is a schematic diagram of the semiconductor structure formation process in one embodiment of the present invention;
[0028] Figure 6 This is a schematic diagram of the semiconductor structure formation process in another embodiment of the present invention;
[0029] Figure 7 and Figure 8 This is a schematic diagram of the semiconductor structure formation process in another embodiment of the present invention;
[0030] Figure 9 and Figure 10 This is a schematic diagram of the semiconductor structure formation process in another embodiment of the present invention;
[0031] Figure 11 This is a schematic diagram of the semiconductor structure formation process in another embodiment of the present invention;
[0032] Figure 12This is a schematic diagram of the semiconductor structure formation process in another embodiment of the present invention. Detailed Implementation
[0033] As described in the background section, there is a need to effectively and quickly solve the problem of wafer warpage.
[0034] Specifically, a wafer includes functional and non-functional surfaces. After depositing a series of films on the wafer surface and annealing the wafer, it undergoes deformation. The deformed wafer is either saddle-shaped or bowl-shaped. A saddle-shaped wafer deforms downwards, with the center of curvature of the warped surface located on the non-functional surface side. A bowl-shaped wafer deforms upwards, with the center of curvature of the warped surface located on the functional surface side. The deformed wafer affects the yield of subsequently formed products.
[0035] To address the aforementioned problems, this invention provides a method for forming a semiconductor structure. After laser annealing the wafer, the wafer warpage is measured to determine if warpage has occurred. Based on the warpage condition, ion implantation is performed on the non-functional surfaces of the wafer until the warpage returns to normal. This method only requires detecting the wafer warpage on the existing equipment and selecting the appropriate solution based on the direction and degree of warpage, thus offering convenient operation and low cost. Furthermore, the stress can be flexibly adjusted by modifying the ion implantation energy, implantation dose, and ion type according to the degree of wafer warpage, thereby effectively and flexibly adjusting the wafer warpage. In summary, this method effectively reduces the risks to subsequent processes caused by wafer warpage deformation.
[0036] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0037] Figure 1 This is a schematic flowchart of the semiconductor structure formation method in an embodiment of the present invention; Figures 2 to 5 This is a schematic diagram of the semiconductor structure formation process in one embodiment of the present invention.
[0038] Please refer to Figure 1 The method for forming the semiconductor structure includes:
[0039] Step S10: Provide a wafer, the wafer including functional and non-functional surfaces;
[0040] Step S20: Form a first stress film layer structure on the non-functional surface;
[0041] Step S30: Perform laser annealing on the wafer;
[0042] Step S40: After laser annealing the wafer, the warpage of the wafer is obtained to determine whether the wafer has warped.
[0043] Step S50: If the wafer warps, obtain the warping details of the wafer;
[0044] Step S60: Based on the warpage of the wafer, perform ion implantation on the non-functional surface of the wafer until the warpage of the wafer returns to normal.
[0045] The method described only requires detecting the wafer warpage on the original equipment, selecting the appropriate solution based on the direction and degree of warpage, thus offering ease of operation and low cost. Furthermore, it allows for flexible adjustment of stress levels by modifying the ion implantation energy, implantation dose, and ion type, based on the degree of wafer warpage, thereby effectively and flexibly adjusting wafer warpage. In summary, this method effectively reduces the risks to subsequent processes caused by wafer warpage deformation.
[0046] The steps will now be analyzed and explained with reference to the accompanying drawings.
[0047] Please combine Figure 2 Continue to refer to Figure 1 Step S10: Provide a wafer 200, the wafer 200 including a functional surface A and a non-functional surface B; Step S20: Form a first stress film layer structure 202 on the non-functional surface B.
[0048] In this embodiment, while forming the first stress membrane layer structure 202 on the non-functional surface B, the embodiment also includes forming a second stress membrane layer structure 201 on the functional surface A.
[0049] The functional surface A is used to form a semiconductor device structure. Typically, a series of processes such as deposition, etching, and ion implantation are performed on the functional surface A to form a semiconductor device. When a series of film layers are deposited on the functional surface A to form the second stress film layer structure 201, a series of film layers are also deposited on the non-functional surface B to form the first stress film layer structure 202. The stacking of multiple film layers generates stress on the wafer 200. The stress film layer on the functional surface A undergoes various subsequent processes to form a semiconductor structure, while the stress film layer on the non-functional surface B does not form a semiconductor structure. After subsequent annealing, the stress is released from all sides, resulting in an imbalance of stress between the non-functional surface B and the functional surface A of the wafer 200, causing the wafer 200 to warp.
[0050] In this embodiment, the material of the wafer 200 is silicon.
[0051] In other embodiments, the wafer material includes silicon carbide, silicon germanium, a multi-element semiconductor material composed of group III-V elements, silicon-on-insulator (SOI), or germanium-on-insulator (GOI). The multi-element semiconductor material composed of group III-V elements includes InP, GaAs, GaP, InAs, InSb, InGaAs, or InGaAsP.
[0052] Please combine Figure 3 Continue to refer to Figure 1 Step S30: Perform laser annealing on the wafer 200.
[0053] Laser annealing is a CO2 laser annealing method with a wavelength of 9.2–10.8 μm, used to eliminate stress and repair lattice defects.
[0054] Please continue to combine Figure 3 Continue to refer to Figure 1 Step S40: After laser annealing the wafer 200, the warpage of the wafer 200 is obtained to determine whether the wafer 200 has warped.
[0055] The method for obtaining the warpage of wafer 200 and determining whether wafer 200 has warped includes: obtaining the warpage of wafer 200; if the warpage is within a preset range, then it is determined that wafer 200 has not warped; if the warpage is greater than the preset range, then it is determined that wafer 200 has warped.
[0056] Please continue to combine Figure 3 Continue to refer to Figure 1 Step S50: If the wafer 200 warps, obtain the warping status of the wafer 200.
[0057] The warpage of the wafer 200 includes: warpage direction, which includes upward warpage and downward warpage. The upward warpage includes: the center of curvature of the warpage surface of the wafer 200 is located on one side of the functional surface A, i.e., bowl-shaped, and the wafer surface generates tensile stress; the downward warpage includes: the center of curvature of the warpage surface of the wafer 200 is located on one side of the non-functional surface B, i.e. saddle-shaped, and the wafer surface generates compressive stress.
[0058] Figure 3 The wafer 200 shown has an upward warping direction, and the center of curvature R of the warped surface of the wafer 200 is located on one side of the functional surface A, i.e., bowl-shaped. Tensile stress is generated on the wafer surface.
[0059] In this embodiment, the warpage of the wafer 200 further includes the bend value of the wafer 200. The bend value is used to measure the degree of bending of the wafer 200; the greater the bend value, the greater the degree of bending of the wafer 200.
[0060] The method for forming the semiconductor structure further includes: when the curvature of the wafer 200 is greater than a preset value range, performing a first thinning process on the first stress film layer structure 202; and when the curvature of the wafer 200 is less than a preset value range, performing a second thinning process on the first stress film layer structure 202.
[0061] In this embodiment, the preset value range is: curvature less than 100.
[0062] In this embodiment, the thinning thickness of the first thinning process is greater than that of the second thinning process. That is, the greater the curvature of the wafer 200, the greater the thinning of the first stress film structure 202, and thinning the first stress film structure 202 can alleviate a certain amount of stress.
[0063] Please refer to Figure 4 , Figure 4 If the curvature of the wafer 200 is greater than 100, the first stress film layer structure 202 is subjected to a first thinning process.
[0064] In this embodiment, when the curvature of the wafer 200 is greater than a preset value range, after the first thinning process is performed on the first stress film layer structure 202, the method further includes: removing part of the remaining first stress film layer structure 202, so that the remaining first stress film layer structure 202 forms a patterned layer (not shown) on the non-functional surface B.
[0065] The projection pattern of the patterned layer onto the non-functional surface B includes a circle or a square. This can further disperse the stress of the first stress membrane structure 202 on the non-functional surface B.
[0066] Please continue to refer to this. Figure 1 Step S60: Based on the warpage of the wafer 200, perform ion implantation on the non-functional surface B of the wafer 200 until the warpage of the wafer 200 returns to normal.
[0067] The warpage of the wafer 200 returns to normal, meaning that the warpage of the wafer 200 meets the preset range.
[0068] Based on the warpage of the wafer 200, ion implantation is performed on the non-functional surface B of the wafer 200, including: if the warpage direction of the wafer 200 is upward, then a first ion is implanted into the non-functional surface B of the wafer 200; if the warpage direction of the wafer 200 is downward, then a second ion is implanted into the non-functional surface B of the wafer 200. The ion implantation energy, implantation dose, and ion type can be adjusted as needed to flexibly adjust the stress level.
[0069] In this embodiment, the molar mass of the first ion is greater than the molar mass of the second ion. The first ion is a heavy ion, and the second ion is a light ion.
[0070] In this embodiment, the molar mass of the first ion is greater than 10, and the first ion includes phosphorus ions or silicon ions, etc.
[0071] In this embodiment, the molar mass of the second ion is less than 10. The second ion includes hydrogen ions or helium ions, etc.
[0072] By adjusting the energy, dosage, and type of ions implanted, the stress can be flexibly adjusted, thus effectively and flexibly controlling wafer warpage. This is because ion implantation causes displacement of the host atoms in the wafer, leading to lattice damage. This damage causes silicon expansion, generating stress on the silicon surface. Furthermore, as the ion implantation dosage increases, the wafer gradually transitions from a single-crystal state to an amorphous state. In addition, ion implantation is often accompanied by annealing. After a certain amount of radiation annealing and thermal annealing, silicon substrate atoms undergo further displacement before amorphization. The type of ions implanted determines the different stresses: light ions generate tensile stress, while heavy ions generate compressive stress.
[0073] When the warpage direction of wafer 200 is upward, tensile stress is generated on the surface of wafer 200. In this case, heavy ion implantation is performed on the non-functional surface B of wafer 200. The compressive stress generated by the heavy ions can neutralize the tensile stress. Conversely, if the warpage direction of wafer 200 is downward, compressive stress is generated on the surface of wafer 200. In this case, light ion implantation is performed on the non-functional surface B of wafer 200. The tensile stress generated by the light ions can neutralize the compressive stress. This achieves the goal of improving wafer warpage.
[0074] Please combine Figure 5 Continue to refer to Figure 1 , Figure 5The wafer 200 is warped upwards. After the first stress film layer structure 202 is thinned, ion implantation is performed on the non-functional surface B of the wafer 200, including: obtaining a continuous warped surface, the continuous warped surface including a first region I and a second region II located on both sides of the first region I, the curvature of the first region I is greater than the curvature of the second region II; performing ion implantation of a first ion P1 on the non-functional surface B of the first region I, and performing ion implantation of a second ion P2 on the non-functional surface B of the second region II.
[0075] After ion implantation is performed on the non-functional surface B of the wafer 200, the warpage of the wafer 200 is restored to a preset range.
[0076] After ion implantation of the non-functional surface B of the wafer 200, the process further includes: performing rapid thermal annealing on the wafer 200. This rapid thermal annealing process is more conducive to uniform ion diffusion on the non-functional surface B of the wafer 200, thereby balancing the stress on the non-functional surface B of the wafer 200 and repairing lattice damage caused by the ion implantation process.
[0077] In this embodiment, the wafer 200 is warped upwards, resulting in tensile stress on its surface. By implanting heavy ions into the first region I with high curvature and light ions into the second region II with low curvature, the stress on the surface of the wafer 200 can be further neutralized and adjusted in different regions, thus avoiding the difficulty of accurately adjusting the warp degree with a single ion implantation.
[0078] After the wafer 200 is subjected to rapid thermal annealing, the first stress film layer structure 202 on the non-functional surface B of the wafer 200 may be removed or not, depending on the requirements.
[0079] Figure 6 This is a schematic diagram of the semiconductor structure formation process in another embodiment of the present invention.
[0080] Please combine Figure 6 Continue to refer to Figure 1 , Figure 6 and Figure 5 The structural difference lies in the fact that the warping direction of the wafer 200 is downward, and the center of curvature R of the warped surface of the wafer 200 is located on one side of the non-functional surface B, i.e., saddle-shaped. Compressive stress is generated on the surface of the wafer 200. The curvature of the wafer 200 is greater than 100°.
[0081] After performing a first thinning process on the first stress film layer structure 202, ion implantation is performed on the non-functional surface B of the wafer 200, including: obtaining a continuous warped surface, the continuous warped surface including a first region I and a second region II located on both sides of the first region I, the curvature of the first region I being greater than the curvature of the second region II; performing ion implantation of a second ion P2 on the non-functional surface B of the first region I, and performing ion implantation of a first ion P1 on the non-functional surface B of the second region II.
[0082] After ion implantation is performed on the non-functional surface B of the wafer 200, the warpage of the wafer 200 is restored to a preset range.
[0083] After ion implantation of the non-functional surface B of the wafer 200, the process further includes: performing rapid thermal annealing on the wafer 200.
[0084] In this embodiment, the wafer 200 is warped downwards, and compressive stress is generated on the surface of the wafer 200. By implanting light ions into the first region I with large curvature and heavy ions into the second region II with small curvature, the stress on the surface of the wafer 200 can be further neutralized and adjusted in different regions to avoid the difficulty of accurately adjusting the warp degree by single ion implantation.
[0085] Figure 7 and Figure 8 This is a schematic diagram of the semiconductor structure formation process in another embodiment of the present invention.
[0086] Please combine Figure 1 refer to Figure 7 , Figure 7 and Figure 5 The structural difference is that the wafer 200 is warped upwards, and the curvature center of the warped surface of the wafer 200 is located on one side of the functional surface A, i.e., bowl-shaped. The surface of the wafer 200 is subjected to tensile stress, and the curvature of the wafer 200 is less than a preset value range, i.e., the curvature of the wafer 200 is less than 100.
[0087] In this embodiment, the curvature of the wafer 200 is less than 100, and the first stress film structure 202 undergoes a second thinning process. This can disperse the stress on the non-functional surface B of the first stress film structure 202.
[0088] After performing a second thinning process on the first stress film layer structure 202, ion implantation is performed on the non-functional surface B of the wafer 200, including: obtaining a continuous warped surface, the continuous warped surface including a first region I and a second region II located on both sides of the first region I, the curvature of the first region I being greater than the curvature of the second region II; and performing ion implantation of a first ion P1 on the non-functional surface B of the first region I.
[0089] Please combine Figure 1 refer to Figure 8 After ion implantation of the first ion P1 into the non-functional surface B of the first region I, the degree of warpage relief of the wafer 200 is obtained; if the degree of warpage of the wafer 200 is relieved and the degree of warpage of the wafer 200 is greater than a preset value range, the second ion P2 is implanted into the non-functional surface B of the second region II.
[0090] In this embodiment, the wafer 200 is warped upwards, resulting in tensile stress on its surface. By implanting heavy ions into the first region I (with high curvature) and light ions into the second region II (with low curvature) in stages, the stress on the wafer 200 surface can be further neutralized in a regional manner, preventing the inaccurate adjustment of warp degree caused by single ion implantation.
[0091] Figure 9 and Figure 10 This is a schematic diagram of the semiconductor structure formation process in another embodiment of the present invention.
[0092] Please combine Figure 1 refer to Figure 9 , Figure 9 and Figure 7 The structural difference lies in the fact that the warping direction of the wafer 200 is downward, and the center of curvature R of the warped surface of the wafer 200 is located on one side of the non-functional surface B, i.e., saddle-shaped. Compressive stress is generated on the surface of the wafer 200. The curvature of the wafer 200 is less than 100°.
[0093] After performing a second thinning process on the first stress film layer structure 202, ion implantation is performed on the non-functional surface B of the wafer 200, including: obtaining a continuous warped surface, the continuous warped surface including a first region I and a second region II located on both sides of the first region I, the curvature of the first region I being greater than the curvature of the second region II; and performing ion implantation of a second ion P2 on the non-functional surface B of the first region I.
[0094] Please combine Figure 1 refer to Figure 10 After ion implantation of the second ion P2 into the non-functional surface B of the first region I, the degree of warpage relief of the wafer 200 is obtained; if the degree of warpage of the wafer 200 is relieved and the degree of warpage of the wafer 200 is greater than a preset value range, the first ion P1 is implanted into the non-functional surface B of the second region II.
[0095] In this embodiment, the wafer 200 is warped downwards, resulting in compressive stress on its surface. By implanting light ions into the first region I with high curvature and heavy ions into the second region II with low curvature in stages, the stress on the wafer 200 surface can be further neutralized in a regional manner, so as to avoid the difficulty of accurately adjusting the warp degree with a single ion implantation.
[0096] Figure 11 This is a schematic diagram of the semiconductor structure formation process in another embodiment of the present invention.
[0097] Please combine Figure 1 refer to Figure 11 , Figure 11 Structure and Figure 5 The structural difference is that the wafer 200 is warped upwards, and the curvature center of the warped surface of the wafer 200 is located on one side of the functional surface A, i.e., bowl-shaped. The surface of the wafer 200 is subjected to tensile stress, and the curvature of the wafer 200 is less than a preset value range, i.e., the curvature of the wafer 200 is less than 100.
[0098] In this embodiment, the curvature of the wafer 200 is less than 100, and the first stress film structure 202 undergoes a second thinning process. This can disperse the stress on the non-functional surface B of the first stress film structure 202.
[0099] After performing a second thinning process on the first stress film layer structure 202, ion implantation is performed on the non-functional surface B of the wafer 200, including: obtaining a continuous warped surface, the continuous warped surface including a first region I and a second region II located on both sides of the first region I, the curvature of the first region I being greater than the curvature of the second region II; and performing ion implantation of a first ion P1 on the non-functional surface B of the first region I and the non-functional surface B of the second region II.
[0100] In this embodiment, wafer 200 is warped upwards, resulting in tensile stress on its surface. By implanting heavy ions into the non-functional surface B of wafer 200, the compressive stress generated by the heavy ions can neutralize and adjust the tensile stress on the surface of wafer 200.
[0101] Figure 12 This is a schematic diagram of the semiconductor structure formation process in another embodiment of the present invention.
[0102] Please combine Figure 1 refer to Figure 12 , Figure 12 Structure and Figure 11 The structural difference is that the wafer 200 is warped downwards, and the curvature center of the warped surface of the wafer 200 is located on one side of the non-functional surface B, i.e., saddle-shaped. The surface of the wafer 200 is subjected to compressive stress, and the curvature of the wafer 200 is less than a preset value range, i.e., the curvature of the wafer 200 is less than 100.
[0103] After performing a second thinning process on the first stress film layer structure 202, ion implantation is performed on the non-functional surface B of the wafer 200, including: obtaining a continuous warped surface, the continuous warped surface including a first region I and a second region II located on both sides of the first region I, the curvature of the first region I being greater than the curvature of the second region II; and performing ion implantation of a second ion P2 on the non-functional surface B of the first region I and the non-functional surface B of the second region II.
[0104] In this embodiment, wafer 200 is warped downwards, resulting in compressive stress on its surface. By implanting lightweight ions into the non-functional surface B of wafer 200, the tensile stress generated by the lightweight ions can neutralize and adjust the compressive stress on the surface of wafer 200.
[0105] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.
Claims
1. A method for forming a semiconductor structure, characterized in that, include: A wafer is provided, the wafer including functional and non-functional surfaces; A first stress film layer structure is formed on the non-functional surface; The wafer is subjected to laser annealing. After laser annealing, the warpage of the wafer is obtained to determine whether the wafer has warped. If the wafer warps, the warping direction and curvature of the wafer are obtained. The warping direction includes upward warping. The upward warping includes: the curvature center of the warped surface of the wafer is located on one side of the functional surface, and the warping direction of the wafer is upward warping. When the curvature of the wafer is greater than a preset value range, the first stress film layer structure is subjected to a first thinning process; when the curvature of the wafer is less than a preset value range, the first stress film layer structure is subjected to a second thinning process, wherein the thinning thickness of the first thinning process is greater than the thinning thickness of the second thinning process. After thinning the first stress film layer structure, ion implantation is performed on the non-functional surfaces of the wafer according to the wafer warpage until the wafer warpage returns to normal. This includes: obtaining a continuous warped surface, the continuous warped surface including a first region and a second region located on both sides of the first region, the curvature of the first region being greater than the curvature of the second region; performing ion implantation of a first ion on the non-functional surface of the first region, and performing ion implantation of a second ion on the non-functional surface of the second region, the molar mass of the first ion being greater than the molar mass of the second ion, the molar mass of the first ion being greater than 10, and the molar mass of the second ion being less than 10.
2. The method for forming a semiconductor structure as described in claim 1, characterized in that, The preset value range is: curvature less than 100.
3. The method for forming a semiconductor structure as described in claim 1, characterized in that, When the curvature of the wafer is greater than a preset value range, after the first thinning process is performed on the first stress film layer structure, before ion implantation is performed on the non-functional surface of the wafer, the process further includes: removing part of the remaining first stress film layer structure so that the remaining first stress film layer structure forms a patterned layer on the non-functional surface.
4. The method for forming a semiconductor structure as described in claim 3, characterized in that, The projection pattern of the patterned layer onto the non-functional surface includes a circle or a square.
5. The method for forming a semiconductor structure as described in claim 1, characterized in that, Based on the warpage of the wafer, after ion implantation of the non-functional surface of the wafer, the process further includes: performing rapid thermal annealing on the wafer.
6. The method for forming a semiconductor structure as described in claim 1, characterized in that, The method for obtaining the warpage of a wafer and determining whether the wafer has warped includes: obtaining the warpage of the wafer; if the warpage is within a preset range, then determining that the wafer has not warped; if the warpage is greater than the preset range, then determining that the wafer has warped; the wafer warpage returning to a normal state includes: the wafer warpage meeting the preset range.
7. The method for forming a semiconductor structure as described in claim 1, characterized in that, While forming the first stress membrane layer structure on the non-functional surface, the method also includes forming a second stress membrane layer structure on the functional surface.
8. A method for forming a semiconductor structure, characterized in that, include: A wafer is provided, the wafer including functional and non-functional surfaces; A first stress film layer structure is formed on the non-functional surface; The wafer is subjected to laser annealing. After laser annealing, the warpage of the wafer is obtained to determine whether the wafer has warped. If the wafer warps, the warping direction and curvature of the wafer are obtained. The warping direction includes downward warping. The downward warping includes: the curvature center of the warped surface of the wafer is located on one side of the non-functional surface, and the warping direction of the wafer is downward warping. When the curvature of the wafer is greater than a preset value range, the first stress film layer structure is subjected to a first thinning process; when the curvature of the wafer is less than a preset value range, the first stress film layer structure is subjected to a second thinning process, wherein the thinning thickness of the first thinning process is greater than the thinning thickness of the second thinning process. After thinning the first stress film layer structure, ion implantation is performed on the non-functional surfaces of the wafer according to the wafer warpage until the wafer warpage returns to normal. This includes: obtaining a continuous warped surface, the continuous warped surface including a first region and a second region located on both sides of the first region, the curvature of the first region being greater than the curvature of the second region; performing second ion implantation on the non-functional surfaces of the first region, and performing first ion implantation on the non-functional surfaces of the second region, the molar mass of the first ion being greater than the molar mass of the second ion, the molar mass of the first ion being greater than 10, and the molar mass of the second ion being less than 10.
9. A method for forming a semiconductor structure, characterized in that, include: A wafer is provided, the wafer including functional and non-functional surfaces; A first stress film layer structure is formed on the non-functional surface; The wafer is subjected to laser annealing. After laser annealing, the warpage of the wafer is obtained to determine whether the wafer has warped. If the wafer warps, the warping direction and curvature of the wafer are obtained. The warping direction includes upward warping. The upward warping includes: the curvature center of the warped surface of the wafer is located on one side of the functional surface, and the warping direction of the wafer is upward warping. When the curvature of the wafer is greater than a preset value range, the first stress film layer structure is subjected to a first thinning process; when the curvature of the wafer is less than a preset value range, the first stress film layer structure is subjected to a second thinning process, wherein the thinning thickness of the first thinning process is greater than the thinning thickness of the second thinning process. After thinning the first stress film layer structure, ion implantation is performed on the non-functional surfaces of the wafer according to the wafer warpage until the wafer warpage returns to normal. This includes: obtaining a continuous warped surface, the continuous warped surface including a first region and a second region located on both sides of the first region, the curvature of the first region being greater than the curvature of the second region; performing ion implantation of the first ion on the non-functional surfaces of the first region; after performing ion implantation of the first ion on the non-functional surfaces of the first region, obtaining the degree of wafer warpage relief; if the degree of wafer warpage is relieved and the wafer warpage is greater than a preset value range, performing ion implantation of the second ion on the non-functional surfaces of the second region, the molar mass of the first ion being greater than the molar mass of the second ion, the molar mass of the first ion being greater than 10, and the molar mass of the second ion being less than 10.
10. A method for forming a semiconductor structure, characterized in that, include: A wafer is provided, the wafer including functional and non-functional surfaces; A first stress film layer structure is formed on the non-functional surface; The wafer is subjected to laser annealing. After laser annealing, the warpage of the wafer is obtained to determine whether the wafer has warped. If the wafer warps, the warping direction and curvature of the wafer are obtained. The warping direction includes downward warping. The downward warping includes: the curvature center of the warped surface of the wafer is located on one side of the non-functional surface, and the warping direction of the wafer is downward warping. When the curvature of the wafer is greater than a preset value range, the first stress film layer structure is subjected to a first thinning process; when the curvature of the wafer is less than a preset value range, the first stress film layer structure is subjected to a second thinning process, wherein the thinning thickness of the first thinning process is greater than the thinning thickness of the second thinning process. After thinning the first stress film layer structure, ion implantation is performed on the non-functional surfaces of the wafer according to the wafer warpage until the wafer warpage returns to normal. This includes: obtaining a continuous warped surface, the continuous warped surface including a first region and a second region located on both sides of the first region, the curvature of the first region being greater than the curvature of the second region; performing second ion implantation on the non-functional surfaces of the first region; after performing second ion implantation on the non-functional surfaces of the first region, obtaining the degree of wafer warpage relief; if the degree of wafer warpage is relieved and the wafer warpage is greater than a preset value range, performing first ion implantation on the non-functional surfaces of the second region, the molar mass of the first ion being greater than the molar mass of the second ion, the molar mass of the first ion being greater than 10, and the molar mass of the second ion being less than 10.