Process method applied to back-end process of semiconductor manufacturing
The formation of oxide layers through photolithography, wet etching and argon bombardment solves the electrochemical corrosion defect of metal welding pads and improves the reliability and yield of semiconductor devices.
Patent Information
- Application Number
- CN202510476626.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2025-08-12
AI Technical Summary
In the prior art, metal welding pads are prone to electrochemical corrosion defects in the post-stage process of semiconductor manufacturing, especially after high-temperature heat treatment, corrosion further expands, affecting device reliability and yield.
The metal welding pad area is exposed through the photolithography process. After etching with fluorine-containing gas, wet etching and argon bombardment are combined to form an oxide layer to reduce the fluorine element content and reduce crystallization defects.
The fluorine content on the surface of the metal welding pad is reduced, and the reliability and yield of the device product are improved.
Smart Images
Figure CN120473436A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor devices and integrated circuit technology, and in particular to a process method used in the back-end process of semiconductor manufacturing. Background Art
[0002] The semiconductor integrated circuit manufacturing process consists of the front-end of line (FEOL) and back-end of line (BEOL) processes. The BEOL process involves forming several metal layers on the wafer with integrated transistors to achieve electrical connections. These layers are then connected via metal pads on the top. Intermetallic dielectric (IMD) layers are used to insulate and isolate the different metal layers.
[0003] During the production process, metal pads often produce electrochemical corrosion. The reason is that another metal is usually added to the metal pad for doping to adjust the electrical mobility. Due to the uneven distribution, the doped metal will aggregate and nucleate at the crystal surface of the metal pad, forming micro-primary cells in the electrolyte solution, causing the metal pad to be corroded. Especially after high-temperature heat treatment in the furnace tube, the electrochemical corrosion is often aggravated. As time accumulates, if the corrosion continues to extend inward, it will eventually form pits.
[0004] In view of this, it is urgent to provide a process method that improves the current process without adding additional masks to reduce the electrical corrosion defects of the metal pad. Summary of the Invention
[0005] The present application provides a process method for use in the back-end of semiconductor manufacturing, which can solve the problem of the metal pad opening process provided in the related art being prone to forming electrical corrosion defects. The method comprises:
[0006] A wafer is provided, wherein the wafer is used to form a semiconductor device, an insulating layer is formed on the wafer, and a metal pad is formed in the insulating layer;
[0007] Etching is performed by a photolithography process to expose a predetermined area of the metal pad, wherein the gas introduced during the etching process includes a fluorine-containing gas;
[0008] Cleaning the exposed area of the metal pad by a wet etching process;
[0009] Bombarding the exposed area of the metal pad with argon gas;
[0010] An oxide layer is formed on the exposed area of the metal pad.
[0011] In some embodiments, the metal pad includes an aluminum metal layer.
[0012] In some embodiments, after etching by a photolithography process, a crystal defect is formed on the surface of the metal pad, and the chemical formula of the crystal defect is Al x O y F z , x, y, z are natural numbers.
[0013] In some embodiments, during the bombardment of the exposed area of the metal pad with argon gas, the flow rate of the argon gas is 200 SCCM to 500 SCCM.
[0014] In some embodiments, forming an oxide layer in the exposed area of the metal pad includes:
[0015] Oxygen is introduced to form an aluminum oxide layer on the exposed area of the metal pad.
[0016] In some embodiments, during the process of forming the oxide layer on the exposed area of the metal pad, the flow rate of oxygen is 3000 SCCM to 4000 SCCM.
[0017] In some embodiments, the metal pad is doped with metallic copper.
[0018] The technical solution of this application has at least the following advantages:
[0019] In the back-end process of semiconductor manufacturing, after the metal pad in the insulating layer is opened by the photolithography process, the exposed area of the metal pad is bombarded with argon gas to reduce the fluorine content on the surface of the metal pad, thereby reducing crystal defects and improving the reliability and yield of the device product to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0021] Figure 1 This is a flow chart of a process method applied to a back-end process of semiconductor manufacturing provided by an exemplary embodiment of the present application;
[0022] Figures 2 to 5 It is a schematic diagram of the process of opening a metal pad provided by an exemplary embodiment of the present application. DETAILED DESCRIPTION
[0023] The following is a clear and complete description of the technical solutions in this application in conjunction with the accompanying drawings. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.
[0024] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0025] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal connections between two components; they can refer to wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.
[0026] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.
[0027] refer to Figure 1 , which shows a flow chart of a process method applied to a semiconductor manufacturing back-end process provided by an exemplary embodiment of the present application, such as Figure 1 As shown, the method includes:
[0028] In step S1 , a wafer is provided. The wafer is used to form a semiconductor device. An insulating layer is formed on the wafer, and a metal pad is formed in the insulating layer.
[0029] refer to Figure 2 , which shows a cross-sectional schematic diagram of the insulating layer above the metal pad before etching. Figure 2 As shown, a metal pad 210 is formed in the insulating layer 220, and the insulating layer 220 is formed on a wafer ( Figure 2 The metal pad 210 includes an aluminum (Al) metal layer, and the metal pad 210 may be doped with copper (Cu).
[0030] Step S2 , performing etching through a photolithography process to expose a predetermined area of the metal pad, wherein the gas introduced during the etching process includes a fluorine-containing gas.
[0031] refer to Figure 3 , which shows a cross-sectional view of the insulating layer above the metal pad after etching. Figure 3 As shown, the insulating layer 220 may be covered with a photoresist ( Figure 3 (not shown), the photoresist in the target area is removed by exposure and development, and etching is performed to remove the insulating layer 220 in the target area, forming a groove 300 so that the predetermined area of the metal pad 210 is exposed. Since the gas introduced during the etching process includes fluorine (F) gas, a crystal defect 211 is formed on the surface of the metal pad 210. The chemical formula of the crystal defect 211 is Al x O y F z , x, y, z are natural numbers.
[0032] Step S3: Cleaning the exposed area of the metal pad by a wet etching process.
[0033] Step S4: bombarding the exposed area of the metal pad with argon gas.
[0034] refer to Figure 4 , which shows a schematic diagram of bombarding the exposed area of the metal pad with argon (Ar). Figure 4 As shown, argon gas can destroy the crystal defects 211 and reduce the fluorine-containing compounds on the surface of the metal pad 210 .
[0035] Step S5: forming an oxide layer on the exposed area of the metal pad.
[0036] refer to Figure 5 , which shows a cross-sectional schematic diagram of an oxide layer formed in the exposed area of the metal pad. Figure 5 As shown, oxygen gas (O 2 ) may be introduced to form an aluminum oxide layer 212 on the exposed area of the metal pad 210 .
[0037] To summarize, in the embodiments of the present application, in the back-end process of semiconductor manufacturing, after the metal pad in the insulating layer is opened by a photolithography process, the exposed area of the metal pad is bombarded with argon gas to reduce the fluorine content on the surface of the metal pad, thereby reducing crystal defects and improving the reliability and yield of the device product to a certain extent.
[0038] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of this application.
Claims
1. A process method used in the back-end process of semiconductor manufacturing, characterized in that: include: A wafer is provided, wherein the wafer is used to form a semiconductor device, an insulating layer is formed on the wafer, and a metal pad is formed in the insulating layer; Etching is performed by a photolithography process to expose a predetermined area of the metal pad, wherein the gas introduced during the etching process includes a fluorine-containing gas; Cleaning the exposed area of the metal pad by a wet etching process; Bombarding the exposed area of the metal pad with argon gas; An oxide layer is formed on the exposed area of the metal pad.
2. The method according to claim 1, characterized in that The metal pad includes an aluminum metal layer.
3. The method according to claim 2, characterized in that After etching by photolithography, a crystal defect is formed on the surface of the metal pad. The chemical formula of the crystal defect is Al x O y F z , x, y, z are natural numbers.
4. The method according to claim 3, characterized in that During the bombardment of the exposed area of the metal pad with argon gas, the flow rate of the argon gas is 200 SCCM to 500 SCCM.
5. The method according to claim 3, characterized in that The forming of an oxide layer in the area where the metal pad is exposed comprises: Oxygen is introduced to form an aluminum oxide layer on the exposed area of the metal pad.
6. The method according to claim 5, characterized in that During the process of forming the oxide layer in the exposed area of the metal pad, the flow rate of oxygen is 3000 SCCM to 4000 SCCM.
7. The method according to any one of claims 1 to 6, characterized in that: The metal pad is doped with metal copper.