Preparation method of TSV structure
By using the first photoresist layer etching and degluing cleaning process in the preparation of TSV structures, combined with the protection of the second photoresist layer, the machine pollution and uneven problems are solved, and the Cu filling yield is improved.
Patent Information
- Application Number
- CN202410172925.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-06
- Publication Date
- 2025-08-08
AI Technical Summary
During the preparation of the existing TSV structure, the composite film etching machine is prone to contamination, and the uneven side walls of the TSV holes affect the adhesion of the subsequent dielectric layer and seed layer, resulting in abnormal Cu filling process.
The first photoresist layer is etched to form a first groove with a larger width, and a second photoresist layer is deposited as a protective layer after degluing and cleaning. The composite film layer is etched to reveal the second groove of the metal wiring, and finally form a TSV groove.
This reduces pollution to the composite film etching machine, improves the deposition adhesion of the film layer, and improves the filling yield of Cu.
Smart Images
Figure CN120453228A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of semiconductor manufacturing and relates to a method for preparing a TSV structure. Background Art
[0002] In the semiconductor industry, researchers have developed a series of advanced packaging technologies to achieve high-density electronic packaging, superior performance, and lower costs. Three-dimensional (3D) packaging technology, among others, offers excellent electrical performance and reliability, while enabling high packaging density. It is widely used in various high-speed circuits and miniaturized systems.
[0003] Through Silicon Via (TSV) technology is a technique for interconnecting stacked chips in three-dimensional integrated circuits. It achieves electrical interconnection between different chips by creating vertically interconnected TSV structures on silicon wafers. TSV technology maximizes chip stacking density in three dimensions, minimizes interconnect lines between chips, and minimizes overall dimensions. It also significantly improves chip speed and power consumption, making it one of the most compelling technologies in current electronic packaging.
[0004] like Figure 1 , which illustrates a structural schematic diagram of the prior art when preparing a TSV structure, wherein the process steps when preparing the TSV structure include:
[0005] Thinning a silicon (Si) wafer 100;
[0006] forming a silicon oxide (SiO2) layer 400 on the silicon wafer 100;
[0007] forming a photoresist (not shown) and performing photolithography and etching to pattern the silicon oxide layer 400;
[0008] First, the silicon wafer 100 is etched, and then the composite film layer 200 is etched to form a TSV hole 500 that exposes the metal wiring 300.
[0009] However, in this process, after etching the silicon wafer 100, when transferring the composite film layer 200 to the composite film etching machine for etching, it is easy to cause contamination of the composite film etching machine, and since the composite film layer is composed of film layers of different materials, when etching the composite film layer, due to the difference in etching selectivity of film layers of different materials, the side walls of different film layers will become uneven, and this situation is related to the aspect ratio of the TSV hole 500. The uneven side wall surface of the TSV hole 500 will seriously affect the adhesion of the subsequent dielectric layer and seed layer prepared in the TSV hole 500, affecting the copper (Cu) filling process in the TSV hole 500 and causing abnormalities in the Cu filling process.
[0010] Therefore, it is necessary to provide a method for preparing a TSV structure. Summary of the Invention
[0011] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for fabricating a TSV structure, so as to solve the problems of machine contamination and low Cu filling yield caused in the prior art TSV structure fabrication.
[0012] To achieve the above-mentioned and other related objectives, the present invention provides a method for preparing a TSV structure, comprising the following steps:
[0013] Providing a semiconductor substrate, the semiconductor substrate comprising a stacked silicon substrate, a composite film layer and a rewiring layer;
[0014] thinning the silicon substrate;
[0015] Depositing a dielectric layer on the surface of the silicon substrate;
[0016] forming a patterned first photoresist layer on the dielectric layer;
[0017] Patterning the dielectric layer and the silicon substrate to form a first groove penetrating the dielectric layer and the silicon substrate to expose the composite film layer;
[0018] removing the first photoresist layer and performing cleaning;
[0019] forming a second photoresist layer, wherein the second photoresist layer fills the first groove;
[0020] Patterning the second photoresist layer to form a second groove in the first groove that penetrates the second photoresist layer and the composite film layer to expose the metal wiring in the redistribution layer;
[0021] The second photoresist layer is removed to form a TSV groove.
[0022] Optionally, a central axis of the second groove coincides with a central axis of the first groove.
[0023] Optionally, a difference between an opening width of the first groove and an opening width of the second groove is 0.5-5 μm.
[0024] Optionally, an opening width of the second groove is greater than 2 μm.
[0025] Optionally, the TSV groove has a depth of 10-20 μm.
[0026] Optionally, the method for thinning the silicon substrate includes a CMP method, and the thickness of the silicon substrate after thinning is 5 to 15 μm.
[0027] Optionally, the dielectric layer includes one or a combination of a silicon oxide layer and a silicon nitride layer.
[0028] Optionally, the insulating dielectric layer in the composite film layer includes one or a combination of a silicon oxide layer and a silicon nitride layer.
[0029] Optionally, the method further includes depositing a dielectric layer and a TSV column in the TSV groove.
[0030] As described above, the preparation method of the TSV structure of the present invention is to first etch the silicon substrate through the first photoresist layer to form a first groove with a larger opening width in the silicon substrate. After the debonding and cleaning processes, a second photoresist layer is deposited in the first groove, and the second photoresist layer is used as a protective layer for the side wall of the silicon substrate. The composite film layer is etched to prepare a second groove that penetrates the second photoresist layer and the composite film layer to expose the metal wiring in the rewiring layer. After removing the second photoresist layer, the TSV groove is formed.
[0031] After etching the silicon substrate, the present application has the process steps of debonding and cleaning, which can reduce the contamination of the composite film etching machine. The formed TSV groove with a larger width at the top and smaller width at the bottom has a good improvement effect on the subsequent film deposition and can improve the Cu filling yield. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 It shows a schematic diagram of the structure presented when preparing a TSV structure in the prior art.
[0033] Figure 2 Shown is a process flow chart for preparing a TSV structure according to the present invention.
[0034] Figures 3 to 9 The figure shows a schematic structural diagram of each step in preparing a TSV structure according to the present invention.
[0035] Description of Reference Numerals
[0036] 100 silicon wafers
[0037] 200 composite film layer
[0038] 300 Metal Wiring
[0039] 400 silicon oxide layer
[0040] 500 TSV holes
[0041] 110 silicon substrate
[0042] 210 composite film layer
[0043] 310 Metal Wiring
[0044] 410 dielectric layer
[0045] 510 first photoresist layer
[0046] 520 second photoresist layer
[0047] 610 First Groove
[0048] 620 Second Groove
[0049] 700 TSV grooves DETAILED DESCRIPTION
[0050] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.
[0051] For example, when describing the embodiments of the present invention, cross-sectional views of device structures may be partially enlarged to scale for ease of explanation. Furthermore, these schematic views are merely illustrative and should not limit the scope of the present invention. Furthermore, in actual manufacturing, three-dimensional dimensions, including length, width, and depth, should be included.
[0052] For convenience of description, spatially relative terms such as "under," "below," "below," "below," "over," and the like may be used herein to describe the relationship of one element or feature to other elements or features illustrated in the drawings. It will be understood that these spatially relative terms are intended to encompass orientations of the device in use or operation in addition to the orientation depicted in the drawings, and may include embodiments in which the first and second features are formed in direct contact, as well as embodiments in which additional features are formed between the first and second features so that the first and second features may not be in direct contact. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.
[0053] It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.
[0054] See Figure 2 This embodiment provides a method for preparing a TSV structure, comprising the following steps:
[0055] S1: Providing a semiconductor substrate, wherein the semiconductor substrate comprises a stacked silicon substrate, a composite film layer, and a rewiring layer;
[0056] S2: thinning the silicon substrate;
[0057] S3: depositing a dielectric layer on the surface of the silicon substrate;
[0058] S4: forming a patterned first photoresist layer on the dielectric layer;
[0059] S5: patterning the dielectric layer and the silicon substrate to form a first groove penetrating the dielectric layer and the silicon substrate to expose the composite film layer;
[0060] S6: removing the first photoresist layer and cleaning it;
[0061] S7: forming a second photoresist layer, wherein the second photoresist layer fills the first groove;
[0062] S8: patterning the second photoresist layer to form a second groove in the first groove that penetrates the second photoresist layer and the composite film layer to expose the metal wiring in the redistribution layer;
[0063] S9: removing the second photoresist layer to form a TSV groove.
[0064] The preparation method of the TSV structure of this embodiment is to first etch the silicon substrate through the first photoresist layer to form the first groove with a larger opening width in the silicon substrate; after performing the stripping and cleaning processes, deposit the second photoresist layer in the first groove, and use the second photoresist layer as a protective layer for the side wall of the silicon substrate; and etch the composite film layer to prepare the second groove that penetrates the second photoresist layer and the composite film layer to expose the metal wiring in the rewiring layer; after removing the second photoresist layer, the TSV groove is formed.
[0065] After etching the silicon substrate, the present application includes the process steps of debonding and cleaning, which can reduce the contamination of the composite film etching machine. The TSV groove formed with a larger width at the top and smaller width at the bottom has a good improvement effect on the subsequent film deposition and can improve the Cu filling yield.
[0066] The following instructions Figures 3 to 9 , further introduces the preparation method of the TSV structure.
[0067] First, see Figure 2 and Figure 3 , perform step S1 to provide a semiconductor substrate, wherein the semiconductor substrate includes a stacked silicon substrate 110, a composite film layer 210 and a rewiring layer.
[0068] Specifically, the size of the silicon substrate 110 may include, for example, 6 inches, 8 inches, or 12 inches, and the thickness of the silicon substrate 110 may be adjusted as needed. The composite film layer 210 may include components for electrical connection, and the type, quantity, and distribution of the components may be adjusted as needed. The rewiring layer includes metal wiring 310 for electrical connection and an insulating dielectric layer. The number of layers, distribution, and material of the metal wiring 310, as well as the material of the insulating dielectric layer, are not particularly limited.
[0069] The preparation of the semiconductor substrate may include bonding the composite film layer 210 and the redistribution layer, and the specific bonding method is not limited here.
[0070] As an example, the insulating dielectric layer in the composite film layer 210 may include one or a combination of a silicon oxide layer and a silicon nitride layer.
[0071] Specifically, when the insulating dielectric layer in the composite film layer 210 uses a silicon oxide layer and / or a silicon nitride layer, since the diffusion of copper (Cu) metal in silicon oxide and silicon nitride is low, the diffusion of Cu metal formed in subsequent processes can be effectively avoided, thereby achieving a good isolation and insulation effect.
[0072] The material of each film layer in the composite film layer 210 and the specific number of layers can be selected according to needs and are not overly limited here.
[0073] Next, see Figure 2 and Figure 3 , executing step S2 to thin the silicon substrate 110.
[0074] Specifically, in order to reduce the size of the device finally prepared, it is preferred to perform a thinning operation on the silicon substrate 110 in the semiconductor base, wherein the thinning process method may include, but is not limited to, chemical mechanical polishing (CMP), and may also include mechanical polishing, etc. In this embodiment, in order to improve the flatness of the silicon substrate 110 after polishing, it is preferred to use CMP for thinning.
[0075] The thickness of the thinned silicon substrate 110 may be 5 to 15 μm, such as 5 μm, 10 μm, 15 μm, etc., and may be set according to actual needs without any excessive limitation.
[0076] Next, see Figure 2 and Figure 4 , executing step S3 , depositing a dielectric layer 410 on the surface of the silicon substrate 110 .
[0077] As an example, the dielectric layer 410 may include one or a combination of a silicon oxide layer and a silicon nitride layer. The dielectric layer 410 can be used as a hard mask for subsequent etching processes, and the dielectric layer 410 can also be used as an insulating layer. Regarding the specific preparation method, type and thickness of the dielectric layer 410, no excessive restrictions are imposed here.
[0078] Next, see Figure 2 and Figure 5 , executing step S4 to form a patterned first photoresist layer 510 on the dielectric layer 410 .
[0079] Specifically, the patterned first photoresist layer 510 may be formed on the dielectric layer 410 by coating, exposing, and developing. The specific type of the first photoresist layer 510 is not particularly limited.
[0080] Next, see Figure 2 and Figure 6 , executing step S5 , patterning the dielectric layer 410 and the silicon substrate 110 to form a first groove 610 penetrating the dielectric layer 410 and the silicon substrate 110 to expose the composite film layer 210 .
[0081] Specifically, after patterning the first photoresist layer 510, the dielectric layer 410 and the silicon substrate 110 may be etched to form the first groove 610 that penetrates the dielectric layer 410 and the silicon substrate 110 and exposes the composite film layer 210. Figure 6 , the opening width of the first groove 610 is marked as D. The data on the opening width D of the first groove 610, the opening morphology and the position distribution of the first groove 610 can be set according to the requirements of the TSV structure to be finally prepared, and no excessive restrictions are imposed here.
[0082] Next, see Figure 2 and Figure 6 , perform step S6 to remove the first photoresist layer 510 and perform cleaning. This step can effectively remove the contaminants generated during the etching of the silicon substrate 110 to avoid subsequent contamination of the composite film etching machine.
[0083] Next, see Figure 2 and Figure 7 , performing step S7 to form a second photoresist layer 520 , and the second photoresist layer 520 fills the first groove 610 .
[0084] The type of the second photoresist layer 520 is not particularly limited, and the second photoresist layer 520 may be made of the same material as the first photoresist layer 510 , but is not limited thereto.
[0085] Afterwards, see Figure 2 and Figure 8 , executing step S8, patterning the second photoresist layer 520, forming a second groove 620 in the first groove 610 that penetrates the second photoresist layer 520 and the composite film layer 210 to expose the metal wiring 310 in the re-wiring layer.
[0086] Specifically, the second photoresist layer 520 may be exposed and developed to pattern the second photoresist layer 520, and then the composite film layer 210 may be etched to form a second groove 620 in the first groove 610 that penetrates the second photoresist layer 520 and the composite film layer 210 and exposes the metal wiring 310 in the rewiring layer. Figure 8 , the opening width of the second groove 620 is marked as d. The data on the opening width d of the second groove 620, the opening morphology and the position distribution of the second groove 620 can be set according to the requirements of the TSV structure to be finally prepared, and no excessive restrictions are made here.
[0087] Since the second groove 620 extends downward from the first groove 610, the opening width d of the second groove 620 is smaller than the opening width D of the first groove 610, and d<D. Therefore, when etching to form the second groove 620, the second photoresist layer 520 attached to the sidewall of the silicon substrate 110 can serve as a protective layer for the silicon substrate 110, thereby improving isolation reliability, effectively preventing the subsequently prepared metal Cu from diffusing into the silicon substrate 110, and improving device yield.
[0088] As an example, the difference between the opening width D of the first groove 610 and the opening width d of the second groove 620 may be 0.5-5 μm, such as 0.5 μm, 1 μm, 2 μm, 3 μm, 5 μm, etc.
[0089] It is preferred that the central axis of the second groove 620 coincides with the central axis of the first groove 610 , so that the second photoresist layer 520 is evenly distributed around the periphery of the second groove 620 , thereby further improving isolation reliability.
[0090] Next, see Figure 2 and Figure 9 , perform step S9 to remove the second photoresist layer 520 to form a TSV groove 700.
[0091] As an example, the depth of the formed TSV groove 700 may be 10-20 μm, such as 10 μm, 15 μm, 20 μm, etc. The selection of the specific morphology and data of the TSV groove 700 is not excessively limited here.
[0092] Specifically, after removing the second photoresist layer 520 , the TSV groove 700 can be formed with an upper opening width D larger than a lower opening width d, thereby facilitating subsequent film deposition in the TSV groove 700 , improving the adhesion of the film deposition, and increasing the Cu filling yield.
[0093] After completing step S9 , a dielectric layer (not shown) may be deposited in the TSV groove 700 , and steps related to preparing TSV pillars (not shown) may be performed to ultimately form the TSV structure (not shown).
[0094] Among them, the dielectric layer may include a stack of layers such as a barrier layer, an adhesion layer and a metal seed layer, but is not limited thereto. The type and specific preparation method of the dielectric layer can be set as needed; the TSV column may be a Cu column prepared by electroplating, but the preparation method is not limited thereto.
[0095] To sum up, the preparation method of the TSV structure of the present invention is to first etch the silicon substrate through the first photoresist layer to form a first groove with a larger opening width in the silicon substrate. After the debonding and cleaning processes, the second photoresist layer is deposited in the first groove, and the second photoresist layer is used as a protective layer for the side wall of the silicon substrate. The composite film layer is etched to prepare a second groove that penetrates the second photoresist layer and the composite film layer to reveal the metal wiring in the rewiring layer. After removing the second photoresist layer, the TSV groove is formed.
[0096] After etching the silicon substrate, the present application has the process steps of debonding and cleaning, which can reduce the contamination of the composite film etching machine. The formed TSV groove with a larger width at the top and smaller width at the bottom has a good improvement effect on the subsequent film deposition and can improve the Cu filling yield.
[0097] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.
Claims
1. A method for preparing a TSV structure, characterized in that: The following steps are involved: Providing a semiconductor substrate, the semiconductor substrate comprising a stacked silicon substrate, a composite film layer and a rewiring layer; thinning the silicon substrate; Depositing a dielectric layer on the surface of the silicon substrate; forming a patterned first photoresist layer on the dielectric layer; Patterning the dielectric layer and the silicon substrate to form a first groove penetrating the dielectric layer and the silicon substrate to expose the composite film layer; removing the first photoresist layer and performing cleaning; forming a second photoresist layer, wherein the second photoresist layer fills the first groove; Patterning the second photoresist layer to form a second groove in the first groove that penetrates the second photoresist layer and the composite film layer to expose the metal wiring in the redistribution layer; The second photoresist layer is removed to form a TSV groove.
2. The method for preparing a TSV structure according to claim 1, wherein: The central axis of the second groove coincides with the central axis of the first groove.
3. The method for preparing a TSV structure according to claim 1, wherein: The difference between the opening width of the first groove and the opening width of the second groove is 0.5 to 5 μm.
4. The method for preparing a TSV structure according to claim 1, wherein: The opening width of the second groove is greater than 2 μm.
5. The method for preparing a TSV structure according to claim 1, wherein: The depth of the TSV groove is 10-20 μm.
6. The method for preparing a TSV structure according to claim 1, wherein: The method for thinning the silicon substrate includes a CMP method, and the thickness of the silicon substrate after thinning is 5 to 15 μm.
7. The method for preparing a TSV structure according to claim 1, wherein: The dielectric layer includes one or a combination of a silicon oxide layer and a silicon nitride layer.
8. The method for preparing a TSV structure according to claim 1, wherein: The insulating dielectric layer in the composite film layer includes one or a combination of a silicon oxide layer and a silicon nitride layer.
9. The method for preparing a TSV structure according to claim 1, wherein: The method also includes the step of depositing a dielectric layer and a TSV column in the TSV groove.