Ap method of a substrate
By obtaining the APC process time based on the thickness of the top sub-substrate and the APC process factor, and dynamically adjusting the thickness of the pre-oxidation layer, the problem of performance fluctuation in thin-film devices in CMOS processes is solved, achieving cost reduction and performance improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUA HONG SEMICON WUXI LTD
- Filing Date
- 2022-07-26
- Publication Date
- 2026-06-05
AI Technical Summary
Existing CMOS processes that monitor and optimize the thickness of the sacrificial oxide layer before ion implantation increase production costs or computational complexity, leading to performance fluctuations in thin-film devices.
By obtaining the APC process time based on the thickness of the top sub-substrate and the APC process factor, the thickness of the pre-oxide layer is dynamically adjusted, and a sacrificial oxide layer is formed by wet etching, which simplifies the process steps and improves the performance fluctuations caused by film thickness differences.
Without adding extra process steps, it reduces costs and improves the electrical performance stability of thin-film devices, while simplifying the APC process flow.
Smart Images
Figure CN115188667B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field, specifically to an APC method for a substrate. Background Technology
[0002] In existing CMOS processes, the APC (advanced process control) process prior to ion implantation requires monitoring and optimizing the thickness of the ion-implanted sacrificial oxide (IMP SAC OX) layer. The electrical performance of thin-film devices is highly correlated with the thickness of the film layer. Taking SOI substrates as an example, the thickness of the top silicon layer varies by lot; a 5% fluctuation in film thickness can lead to a 5% fluctuation in device performance. Therefore, monitoring and optimizing the ion-implanted sacrificial oxide layer before ion implantation in CMOS processes is essential.
[0003] Currently, there are two main methods to mitigate performance fluctuations caused by film thickness in thin-film devices before ion implantation in CMOS processes:
[0004] Method 1: Add process steps to control the thickness of top silicon. Additional process steps generally include RTO / FNC to consume top silicon to control film thickness, WET to remove oxygen, and forming a uniform top silicon thickness, etc.
[0005] Method 2: APC adjusts the IMP dose of device ion implantation for each product and each device;
[0006] Method 1 requires additional process steps to adjust the thickness of the top silicon, increasing the production and manufacturing costs; Method 2 involves complex calculations and incurs higher costs. Summary of the Invention
[0007] This application provides an APC method for substrates that can solve the problem of high investment costs in current measures to improve film thickness before ion implantation in CMOS processes for thin film devices, which can address the performance fluctuations caused by such measures.
[0008] On one hand, embodiments of this application provide an APC method for a substrate, including:
[0009] A substrate is provided, wherein the substrate comprises, from bottom to top, a stacked bottom sub-substrate layer, an intermediate oxide layer and a top sub-substrate layer;
[0010] An active region process is performed on the substrate, wherein a pre-oxidized layer is formed on the substrate after the active region process is performed;
[0011] The APC process time is obtained based on the thickness of the top sub-substrate layer and the APC process factor.
[0012] The thickness of the pre-oxidized layer is adjusted according to the APC process time to obtain the sacrificial oxide layer;
[0013] The substrate is subjected to an ion implantation process using the sacrificial oxide layer.
[0014] Optionally, in the APC method for the substrate, the step of obtaining the APC process time based on the thickness of the top sub-substrate layer and the APC process factor includes:
[0015] The thickness of the sacrificial oxide layer is obtained based on the thickness of the top sub-substrate layer and the APC process coefficient;
[0016] Based on the thickness of the sacrificial oxide layer, the thinning thickness of the pre-oxide layer corresponding to the ion implantation process is obtained;
[0017] The APC process time is obtained based on the thinning thickness of the pre-oxidized layer.
[0018] Optionally, in the APC method for the substrate, the step of obtaining the thickness of the sacrificial oxide layer based on the thickness of the top sub-substrate layer and the APC process factor satisfies the following formula:
[0019] Tpost = k × H;
[0020] Where Tpost is the thickness of the sacrificial oxide layer, H is the thickness of the top sub-substrate layer, and k is the APC process coefficient.
[0021] Optionally, in the APC method for the substrate, the APC process coefficient ranges from 0 to 1.
[0022] Optionally, in the APC method for the substrate, the step of obtaining the thinning thickness of the pre-oxide layer corresponding to the ion implantation process based on the thickness of the sacrificial oxide layer satisfies the following formula:
[0023] ΔT = Tpost - Tpre;
[0024] Wherein, ΔT is the thinning thickness of the pre-oxidized layer, and Tpre is the thickness of the pre-oxidized layer.
[0025] Optionally, in the APC method for the substrate, the step of obtaining the APC process time based on the thinning thickness of the pre-oxidized layer includes:
[0026] t = ΔT / Er;
[0027] Where t is the APC process time and Er is the etching rate.
[0028] Optionally, in the APC method for the substrate, adjusting the thickness of the pre-oxide layer to obtain the sacrificial oxide layer according to the APC process time includes:
[0029] According to the APC process time, the pre-oxide layer is etched using a wet etching process to obtain a sacrificial oxide layer.
[0030] The technical solution of this application has at least the following advantages:
[0031] This application simplifies the APC process by directly obtaining the APC process time in advance based on the thickness of the top sub-substrate layer and the APC process coefficient before performing the ion implantation process on the substrate. This allows for dynamic adjustment of the thickness of the pre-oxidation layer on different device regions and / or different batches of LO substrates, thus simplifying the APC process. Consequently, no additional process steps are needed before ion implantation in the CMOS process of thin-film devices. This conveniently mitigates the impact of device performance fluctuations caused by differences in film thickness between different batches of substrates, reduces process costs, and improves the electrical performance of thin-film devices. Attached Figure Description
[0032] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0033] Figure 1 This is a flowchart of the APC method for a substrate according to an embodiment of the present invention;
[0034] Figure 2 This is a schematic diagram of the bulk structure of the substrate according to an embodiment of the present invention;
[0035] Figure 3 This is a schematic diagram of a semiconductor structure with a pre-oxidized layer formed on a substrate according to an embodiment of the present invention;
[0036] Figure 4 This is a schematic diagram of a semiconductor structure with a sacrificial oxide layer formed after thinning, according to an embodiment of the present invention.
[0037] The reference numerals in the attached figures are explained as follows:
[0038] 10-Substrate, 11-Bottom sub-substrate layer, 12-Intermediate oxide layer, 13-Top sub-substrate layer, 21-Pre-oxide layer, 22-Sacrificial oxide layer. Detailed Implementation
[0039] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0040] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated 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.
[0041] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0042] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.
[0043] This application provides an APC method for a substrate. Please refer to [link / reference]. Figure 1 , Figure 1 This is a flowchart of an APC method for a substrate according to an embodiment of the present invention. The APC method for the substrate includes:
[0044] Step S10: Please refer to Figure 2 , Figure 2 This is a schematic diagram of the substrate structure according to an embodiment of the present invention. A substrate 10 is provided, wherein the substrate 10 comprises, from bottom to top, a stacked bottom sub-substrate layer 11, an intermediate oxide layer 12, and a top sub-substrate layer 13.
[0045] Step S20: Please refer to Figure 3 , Figure 3This is a schematic diagram of a semiconductor structure with a pre-oxide layer formed on a substrate according to an embodiment of the present invention. An active region process (ACT Loop) is performed on the substrate 10. Specifically, some active regions can be defined on the substrate 10, and the process may further include a step of forming a shallow trench isolation structure in the substrate. After performing the active region process, a pre-oxide layer 21 is formed on the substrate 10. In this embodiment, it is worth noting that the pre-oxide layer 21 can be a combination of a pad oxide layer and a pre-existing sacrificial oxide layer formed during the active region process; or it can be simply a pre-existing sacrificial oxide layer formed during the active region process.
[0046] Step S30: Obtain the APC process time based on the thickness of the top sub-substrate layer 13 and the APC process coefficient.
[0047] Furthermore, step S30 may specifically include:
[0048] Step S30.1: Obtain the thickness of the sacrificial oxide layer 22 based on the thickness of the top sub-substrate layer 13 and the APC process coefficient. Step S30.1 satisfies the following formula:
[0049] Tpost = k × H;
[0050] Where Tpost is the thickness of the sacrificial oxide layer, H is the thickness of the top sub-substrate layer, and k is the APC process coefficient.
[0051] Preferably, the APC process coefficient ranges from 0 to 1, for example, 0.5 or 0.7.
[0052] In this embodiment, the specific value of the APC process coefficient can be calculated using a linear regression equation based on the APC process data (thickness of the sacrificial oxide layer, thinning thickness, etc.) from at least 10 previous batches.
[0053] Step S30.2: Based on the thickness of the pre-oxidized layer 21, obtain the thinning thickness of the pre-oxidized layer 21 corresponding to the ion implantation process. Step S30.2 satisfies the following formula:
[0054] ΔT = Tpost - Tpre;
[0055] Wherein, ΔT is the thinning thickness of the pre-oxidized layer 21, and Tpre is the thickness of the pre-oxidized layer 21.
[0056] Step S30.3: Obtain the APC process time based on the thinning thickness of the pre-oxidized layer 21.
[0057] Step S30.3 includes:
[0058] t = ΔT / Er;
[0059] Where t is the APC process time and Er is the etching rate.
[0060] Step S40: Please refer to Figure 4 , Figure 4 This is a schematic diagram of a semiconductor structure after thinning to form a sacrificial oxide layer according to an embodiment of the present invention. The thickness of the pre-oxide layer 21 is adjusted according to the APC process time to obtain the sacrificial oxide layer 22. Specifically, in this embodiment, a wet etching process can be used to etch the pre-oxide layer 21 to obtain the sacrificial oxide layer 22.
[0061] Step S50: Perform an ion implantation process on the substrate 10 using the sacrificial oxide layer 22.
[0062] In summary, the present invention provides an APC method for a substrate, comprising: providing a substrate 10, wherein the substrate 10 comprises, from bottom to top, a stacked bottom sub-substrate layer 11, an intermediate oxide layer 12, and a top sub-substrate layer 13; performing an active region process on the substrate 10, wherein, after performing the active region process, a pre-oxide layer 21 is formed on the substrate 10; obtaining an APC process time based on the thickness of the top sub-substrate layer 13; adjusting the thickness of the pre-oxide layer 21 based on the APC process time to obtain a sacrificial oxide layer 22; and performing an ion implantation process on the substrate 10 using the sacrificial oxide layer 22. This application simplifies the APC process by directly obtaining the APC process time in advance based on the thickness of the top sub-substrate layer 13 and the APC process coefficient before performing the ion implantation process on the substrate 10. This allows for dynamic adjustment of the thickness of the pre-oxidized layer 21 on the substrate in different device regions and / or different batches, thus simplifying the APC process. Consequently, no additional process steps are needed before ion implantation in the CMOS process of thin-film devices. This conveniently mitigates the impact of device performance fluctuations caused by differences in the film thickness of different batches of substrates, reduces process costs, and improves the electrical performance of thin-film devices.
[0063] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.
Claims
1. An APC method for a substrate, characterized in that, include: A substrate is provided, wherein the substrate comprises, from bottom to top, a stacked bottom sub-substrate layer, an intermediate oxide layer and a top sub-substrate layer; An active region process is performed on the substrate, wherein a pre-oxidized layer is formed on the substrate after the active region process is performed; The thickness of the sacrificial oxide layer is obtained based on the thickness of the top sub-substrate layer and the APC process coefficient; Based on the thickness of the sacrificial oxide layer, the thinning thickness of the pre-oxide layer corresponding to the ion implantation process is obtained; The APC process time is obtained based on the thinning thickness of the pre-oxidized layer; The thickness of the pre-oxidized layer is adjusted according to the APC process time to obtain the sacrificial oxide layer; The substrate is subjected to an ion implantation process using the sacrificial oxide layer. in, The step of obtaining the thickness of the sacrificial oxide layer based on the thickness of the top sub-substrate layer and the APC process factor satisfies the following formula: Tpost = k × H; Where Tpost is the thickness of the sacrificial oxide layer, H is the thickness of the top sub-substrate layer, and k is the APC process coefficient; the value of the APC process coefficient ranges from 0 to 1. The step of obtaining the thinning thickness of the pre-oxide layer corresponding to the ion implantation process based on the thickness of the sacrificial oxide layer satisfies the following formula: ∆T = Tpost - Tpre; Where ∆T is the thinning thickness of the pre-oxidized layer, and Tpre is the thickness of the pre-oxidized layer; The step of obtaining the APC process time based on the thinning thickness of the pre-oxidized layer includes: t = ∆T / Er; Where t is the APC process time and Er is the etching rate.
2. The APC method for a substrate according to claim 1, characterized in that, The step of adjusting the thickness of the pre-oxide layer to obtain the sacrificial oxide layer according to the APC process time includes: According to the APC process time, the pre-oxide layer is etched using a wet etching process to obtain a sacrificial oxide layer.