Method for oxidizing a substrate and semiconductor device

Abstract

This invention provides a substrate oxidation method and a semiconductor device. In the substrate oxidation method, a target thickness of the oxide layer to be formed is determined, wherein the target thickness of the oxide layer is greater than 0 μm and less than or equal to 4 μm; based on the target thickness, a target oxygen content and a target nitrogen content of the substrate are determined, wherein the target oxygen content of the substrate is 6 new ppma to 18 new ppma, and the target nitrogen content of the substrate is 1 × 10⁻⁶. 13 atoms / cm 3 ~3×10 15 atoms / cm 3 The process involves providing a substrate with target oxygen and nitrogen contents; determining the oxidation temperature and time based on the target oxide layer thickness; and performing an oxidation process on the substrate to form an oxide layer of the target thickness. This ensures that the size and density of bulk microdefects in the substrate correspond to oxide layers of different target thicknesses, and adjusts the oxidation temperature and time to avoid slip line defects caused by excessively high oxidation temperatures or excessively long oxidation times.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit technology, and in particular to a substrate oxidation method and a semiconductor device. Background Technology

[0002] As integrated circuit (IC) integration density increases, multilayer wiring technology requires increased dielectric layer thickness to reduce parasitic capacitance. When forming oxide layers on silicon substrates, the significant difference in the coefficient of thermal expansion (CTE) between thick oxide layers and the silicon substrate can easily lead to stress-induced cracking or delamination. While process optimization (e.g., annealing) can alleviate stress concentration and improve the uniformity of oxide films—for example, dry-wet oxidation combined with high-temperature annealing can produce thick (>2 μm) and dense silicon oxide films suitable for high-reliability power devices—existing oxidation processes are prone to slip line defects in the substrate. Summary of the Invention

[0003] The purpose of this invention is to provide a substrate oxidation method and a semiconductor device to solve the problem of slip line defects that occur during the oxidation process.

[0004] To address the aforementioned technical problems, this invention provides a method for oxidizing a substrate, comprising: determining a target thickness of an oxide layer to be formed, wherein the target thickness of the oxide layer is greater than 0 μm and less than or equal to 4 μm; and determining a target oxygen content and a target nitrogen content of the substrate based on the target thickness of the oxide layer to be formed, wherein the target oxygen content of the substrate is 6 new ppma to 18 new ppma and the target nitrogen content of the substrate is 1 × 10⁻⁶. 13 atoms / cm 3 ~3×10 15 atoms / cm 3 Provide a substrate having the target oxygen content and target nitrogen content; determine the oxidation temperature and oxidation time of the oxidation process according to the target thickness of the oxide layer; perform an oxidation process on the substrate according to the oxidation temperature and oxidation time of the oxidation process to form an oxide layer of the target thickness on the substrate.

[0005] Optionally, in the substrate oxidation method, when the target thickness of the oxide layer is greater than 0 μm and less than 2 μm, the target oxygen content of the substrate is 6 new ppma to 10 new ppma, and the target nitrogen content of the substrate is 1 × 10⁻⁶. 13 atoms / cm 3 ~ 5×10 13 atoms / cm 3 .

[0006] Optionally, in the substrate oxidation method, when the target thickness of the oxide layer is greater than or equal to 2 μm and less than or equal to 3 μm, the target oxygen content of the substrate is 10 new ppma to 14 new ppma, and the target nitrogen content of the substrate is 1 × 10⁻⁶. 14 atoms / cm 3 ~ 5×10 14 atoms / cm 3 .

[0007] Optionally, in the substrate oxidation method, when the target thickness of the oxide layer is greater than 3 μm and less than or equal to 4 μm, the target oxygen content of the substrate is 14 new ppma to 18 new ppma, and the target nitrogen content of the substrate is 1 × 10⁻⁶. 15 atoms / cm 3 ~3×10 15 atoms / cm 3 .

[0008] Optionally, in the substrate oxidation method, when the target thickness of the oxide layer is greater than 0 μm and less than 2 μm, the oxidation temperature of the oxidation process is 950℃~1050℃ and the oxidation time is 15h~20h.

[0009] Optionally, in the substrate oxidation method, when the target thickness of the oxide layer is greater than or equal to 2 μm and less than or equal to 3 μm, the oxidation temperature of the oxidation process is 1050℃~1100℃ and the oxidation time is 20h~25h.

[0010] Optionally, in the substrate oxidation method, when the target thickness of the oxide layer is greater than 3 μm and less than or equal to 4 μm, the oxidation temperature of the oxidation process is 1100℃~1200℃ and the oxidation time is 25h~30h.

[0011] Based on the same inventive concept, the present invention also provides a semiconductor device, comprising: a substrate and an oxide layer located on the substrate, the oxide layer being formed using the substrate oxidation method described above; wherein the size of the bulk microdefects in the substrate is 50 nm to 100 nm, and the density of the bulk microdefects in the substrate is 5 × 10⁻⁶. 8 cm -3 ~3×10 10 cm -3 .

[0012] Optionally, in the semiconductor device, when the target thickness of the oxide layer is greater than 0 μm and less than 2 μm, the size of the bulk microdefects in the substrate is 50 nm to 60 nm, and the density of the bulk microdefects in the substrate is 5 × 10⁻⁶. 8 cm-3 ~7×10 8 cm -3 Alternatively, when the target thickness of the oxide layer is greater than or equal to 2 μm and less than or equal to 3 μm, the size of the bulk microdefects in the substrate is 70 nm to 80 nm, and the density of the bulk microdefects in the substrate is 5 × 10⁻⁶. 9 cm -3 ~7×10 9 cm -3 Alternatively, when the target thickness of the oxide layer is greater than 3 μm and less than or equal to 4 μm, the size of the bulk microdefects in the substrate is 80 nm to 100 nm, and the density of the bulk microdefects in the substrate is 1 × 10⁻⁶. 10 cm -3 ~3×10 10 cm -3 .

[0013] In the substrate oxidation method provided by this invention, the target thickness of the oxide layer to be formed is first determined, which is greater than 0 μm and less than or equal to 4 μm; then, based on the target thickness, the target oxygen content and target nitrogen content of the substrate are determined, where the target oxygen content is 6 new ppma to 18 new ppma and the target nitrogen content is 1 × 10⁻⁶. 13 atoms / cm 3 ~3×10 15 atoms / cm 3 Next, a substrate with target oxygen and nitrogen contents is provided. Then, based on the target thickness of the oxide layer, the oxidation temperature and oxidation time of the oxidation process are determined. Next, based on the oxidation temperature and oxidation time, the substrate is subjected to an oxidation process to form an oxide layer of the target thickness. Thus, by determining the target oxygen and nitrogen contents of the substrate based on the target thickness of the oxide layer, and using a substrate with corresponding target oxygen and nitrogen contents to perform the oxidation process, the size and density of bulk micro-defects in the substrate corresponding to oxide layers of different target thicknesses are different, thereby enabling bulk micro-defects to effectively resist slip line defects generated during the oxidation process. Simultaneously, the oxidation temperature and oxidation time of the oxidation process are adjusted accordingly based on the target thickness of the oxide layer to avoid slip line defects caused by excessively high oxidation temperatures and excessively long oxidation times, thereby reducing or avoiding the problem of slip line defects in the substrate during the oxidation process. Attached Figure Description

[0014] Figure 1 This is a schematic flowchart of the substrate oxidation method provided in an embodiment of the present invention.

[0015] Figure 2This is a schematic diagram of the structure formed after the oxidation process is performed in the substrate oxidation method provided in the embodiments of the present invention.

[0016] Figure 3 This is a schematic diagram showing the relationship between the substrate bulk micro-defect density and the target oxygen content and target nitrogen content of the substrate in the substrate oxidation method provided in this embodiment of the invention.

[0017] Figure 4 This is a schematic scan of the front side of the substrate after the oxidation process is performed in Embodiment 1 of the substrate oxidation method provided by the present invention.

[0018] Figure 5 This is a schematic scan of the back side of the substrate after the oxidation process is performed in Embodiment 1 of the substrate oxidation method provided by the present invention.

[0019] Figure 6 This is a schematic scan of the front side of the substrate after the oxidation process is performed in Embodiment 2 of the substrate oxidation method provided by the present invention.

[0020] Figure 7 This is a schematic scan of the back side of the substrate after the oxidation process is performed in Embodiment 2 of the substrate oxidation method provided by the present invention.

[0021] Figure 8 This is a schematic scan of the front side of the substrate after the oxidation process is performed in Embodiment 3 of the substrate oxidation method provided by the present invention.

[0022] Figure 9 This is a schematic scan of the back side of the substrate after the oxidation process is performed in Embodiment 3 of the substrate oxidation method provided by the present invention.

[0023] Figure 10 This is a schematic scan of the front side of the substrate after the oxidation process is performed, in Comparative Example 1 of the substrate oxidation method provided by the present invention.

[0024] Figure 11 This is a schematic scan of the back side of the substrate after the oxidation process is performed, in Comparative Example 1 of the substrate oxidation method provided by the present invention.

[0025] Figure 12 This is a schematic scan of the front side of the substrate after the oxidation process is performed, in Comparative Example 2 of the substrate oxidation method provided by the present invention.

[0026] Figure 13 This is a schematic scan of the back side of the substrate after the oxidation process is performed, in Comparative Example 2 of the substrate oxidation method provided by the present invention.

[0027] The reference numerals in the attached figures are explained as follows: 100 - substrate; 100a - slip line; 110 - oxide layer. Detailed Implementation

[0028] The substrate oxidation method and semiconductor device proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only used to facilitate and clarify the illustration of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structure. In particular, different figures may emphasize different aspects and sometimes use different scales.

[0029] Figure 1 This is a schematic flowchart of the substrate oxidation method provided in an embodiment of the present invention. Figure 1 As shown, this embodiment provides a substrate oxidation method, including: Step S1: determining the target thickness of the oxide layer to be formed, wherein the target thickness of the oxide layer is greater than 0 μm and less than or equal to 4 μm; Step S2: determining the target oxygen content and target nitrogen content of the substrate based on the target thickness, wherein the target oxygen content of the substrate is 6 new ppma to 18 new ppma, and the target nitrogen content of the substrate is 1 × 10⁻⁶. 13 atoms / cm 3 ~3×10 15 atoms / cm 3 Step S3: Provide a substrate having the target oxygen content and target nitrogen content; Step S4: Determine the oxidation temperature and oxidation time of the oxidation process according to the target thickness; Step S5: Perform an oxidation process on the substrate according to the oxidation temperature and oxidation time of the oxidation process to form an oxide layer of the target thickness on the substrate.

[0030] The following will be combined with the appendix Figures 2-13 The substrate oxidation method provided in this embodiment will be described in more detail.

[0031] In step S1, the target thickness of the oxide layer to be formed is determined, wherein the target thickness of the oxide layer is greater than 0 μm and less than or equal to 4 μm. Here, the oxide layer 110 to be formed refers to the oxide layer to be formed on the substrate.

[0032] Then, step S2 is performed to determine the target oxygen content and target nitrogen content of the substrate based on the target thickness of the oxide layer to be formed. The target oxygen content of the substrate is 6 new ppma to 18 new ppma, and the target nitrogen content of the substrate is 1 × 10⁻⁶. 13 atoms / cm 3 ~3×10 15 atoms / cm 3Thus, the target oxygen content and target nitrogen content of the substrate are determined according to the target thickness of the oxide layer to be formed, and the subsequent oxidation process is performed using a substrate with the corresponding target oxygen and nitrogen content. This results in different sizes and densities of bulk micro-defects in the substrate corresponding to oxide layers of different target thicknesses, thereby enabling the bulk micro-defects to effectively resist slip line defects generated during the oxidation process.

[0033] In this embodiment, the target thickness of the oxide layer is greater than 0 μm and less than or equal to 4 μm. The target oxygen content of the substrate is 6 new ppma to 18 new ppma. When the unit of the target oxygen content in the substrate is new ppma (atomic ratio), then 1 new ppma is approximately equal to 0.5 ppma (weight ratio), and 1 ppma (weight ratio) is approximately equal to 2.14 × 10⁻⁶. 17 atoms / cm 3 .

[0034] In this embodiment, the target nitrogen content of the substrate is 1×10⁻⁶. 13 atoms / cm 3 ~3×10 15 atoms / cm 3 .

[0035] It should be noted that the target oxygen content of the substrate should not be too low or too high. For example, when the target oxygen content of the substrate is low, such as less than 6 new ppma, the oxygen concentration gradient between the substrate and the subsequently formed oxide layer is large. This results in significant thermal stress during oxide layer growth and subsequent heat treatment. The thermal stress originates from the difference in thermal expansion coefficients between the substrate and the oxide layer, as well as structural differences caused by uneven oxygen concentration distribution. When the thermal stress exceeds the critical shear stress of the material, slip lines are easily induced. When the target oxygen content of the substrate is less than 6 new ppma, the slip line density is roughly inversely proportional to the oxygen content. In other words, the lower the oxygen content, the larger the oxygen concentration gradient, the greater the thermal stress, and the easier it is to generate slip lines. Conversely, when the target oxygen content of the substrate is high, such as greater than 18 new ppma, although the oxygen concentration gradient inside the substrate may decrease, the large amount of oxygen precipitation will become stress concentration points, resulting in localized stress concentration within the subsequently formed oxide layer. When local stress exceeds a critical value, slip lines will form, and the density of slip lines at this point is positively correlated with the oxygen content. Therefore, the more oxygen deposits there are, the more stress concentration points there are, and the greater the probability of slip lines forming. Based on this, in this embodiment, the target oxygen content of the substrate is 6 new ppma to 18 new ppma.

[0036] Furthermore, the nitrogen content in the substrate should not be too low or too high. Specifically, at lower nitrogen contents, the inhibitory effect of nitrogen atoms on oxygen precipitation growth is relatively weak, and the reduction in the size of bulk microdefects is smaller. As the nitrogen content increases, this inhibitory effect gradually strengthens, the size of bulk microdefects decreases significantly, and their distribution becomes more uniform, enabling them to effectively resist slip line defects generated during the oxidation process, thereby reducing or avoiding slip line defects within the substrate during subsequent oxidation processes. However, when the nitrogen content is excessive, excessive aggregation of nitrogen atoms at the interface may lead to increased lattice mismatch and the formation of brittle phases. These factors increase the local stress at the interface. When the local stress exceeds the material's bearing capacity, slip lines are induced, and the slip line density is positively correlated with the nitrogen content. Excessive nitrogen disrupts the stability of the interface and increases the risk of slip line formation. In other words, if there are too many nitrogen atoms, for example, if the nitrogen content in the substrate is greater than 5 × 10⁻⁶, the substrate will be at risk of slip line formation. 15 atoms / cm 3 This can easily occupy the original oxygen precipitation nucleation sites, or bind too tightly to oxygen atoms, thus hindering the diffusion and aggregation of oxygen atoms, and inhibiting the formation of bulk micro-defects, leading to a decrease in the density of bulk micro-defects. Based on this, in this embodiment, the target nitrogen content of the substrate is 1×10⁻⁶. 13 atoms / cm 3 ~3×10 15 atoms / cm 3 .

[0037] Figure 3 This is a schematic diagram illustrating the relationship between the substrate bulk micro-defect density and the target oxygen and nitrogen contents of the substrate in the substrate oxidation method provided in this embodiment of the invention. Figure 3 The first horizontal axis represents the target oxygen content of the substrate, in new ppma, and the second horizontal axis represents the nitrogen content of the substrate, in atoms / cm³. 3 The vertical axis represents the bulk microdefect (BMD) density of the substrate, in cm³. -3 .like Figure 3 As shown, in the low to medium oxygen concentration range, i.e., when the oxygen content in the substrate is 6 new ppma-14 new ppma, the density of bulk microdefects inside substrate 100 is linearly positively correlated with the oxygen content. In the medium nitrogen concentration range, i.e., when the nitrogen content in the substrate is 1×10⁻⁶, the density of bulk microdefects is linearly positively correlated with the oxygen content. 14 atoms / cm 3 ~5×10 14 atoms / cm 3Nitrogen atoms can combine with oxygen atoms to form nitrogen-oxygen complexes. These complexes act as heterogeneous nucleation centers, greatly increasing the nucleation sites for oxygen precipitation. Therefore, in the medium nitrogen concentration range, increasing the nitrogen content within the substrate significantly increases the BMD density. However, with the continuous increase of nitrogen content within the substrate, excessive nitrogen atoms will appear; for example, when the nitrogen content within the substrate exceeds 5 × 10⁻⁶. 15 atoms / cm 3 Excessive nitrogen atoms can occupy the original oxygen precipitation nucleation sites or bind too tightly to oxygen atoms, hindering the diffusion and aggregation of oxygen atoms. This, in turn, inhibits the formation of BMD, leading to a decrease in BMD density. The size of BMD decreases as nitrogen content increases. Therefore, it is not true that the higher the nitrogen and oxygen content, the better.

[0038] In the high oxygen concentration range, i.e., when the oxygen content in the substrate is greater than 18 new ppma, the slip line density is positively correlated with the oxygen content. At this point, nitrogen atoms can form a relatively dense silicon oxynitride layer at the interface between the substrate and the oxide layer. The silicon oxynitride layer enhances the bonding force between the substrate and the oxide layer while inhibiting oxygen atom diffusion and reducing the stress gradient at the interface. This reduces the formation of slip lines. Since the slip line density is inversely proportional to the nitrogen content, it helps reduce slip lines. However, excessive nitrogen can lead to brittle phases; therefore, when the substrate has a high oxygen content, the nitrogen content should not be too high.

[0039] Based on this, in this embodiment, the target oxygen content of the substrate is 6 new ppma to 18 new ppma, and the target nitrogen content of the substrate 100 is 1 × 10⁻⁶. 13 atoms / cm 3 ~5×10 13 atoms / cm 3 Thus, nitrogen atoms within substrate 100 can combine with oxygen atoms to form nitrogen-oxygen complexes. These complexes act as heterogeneous nucleation centers, significantly increasing the nucleation sites for oxygen precipitation. Furthermore, nitrogen atoms within substrate 100 can pin to the oxygen precipitation interface, hindering oxygen diffusion at the precipitation interface and thus limiting the growth rate of oxygen precipitation. Therefore, during the oxidation process, nitrogen atoms can form a relatively dense silicon oxynitride layer at the interface between the substrate and the oxide layer. This interface layer enhances the bonding force between the substrate and the oxide layer; that is, an appropriate amount of nitrogen improves the interface structure, inhibits oxygen diffusion, improves stress distribution, reduces the stress gradient at the interface, and allows the substrate to withstand greater stress, thereby reducing the formation of slip lines.

[0040] The slip line density of a substrate is the result of the combined effect of its target oxygen and nitrogen content. Only when both oxygen and nitrogen contents are appropriate can their synergistic effect effectively reduce stress and decrease slip line formation. However, with high oxygen and excessive nitrogen content, the stress concentration caused by oxygen precipitation and the lattice mismatch caused by nitrogen may overlap, leading to a significant increase in stress and a substantial increase in slip line density. For example, when the target oxygen content of the substrate is high, stress concentration due to oxygen precipitation is already likely. If the nitrogen content is also excessive, the interface lattice mismatch will worsen, further deteriorating the stress distribution and greatly increasing the likelihood of slip line formation.

[0041] Furthermore, the volumetric microdefects within the substrate must not be excessive. Excessive volumetric microdefects can disrupt the integrity of the substrate's crystal structure, leading to decreased mechanical strength and increased susceptibility to breakage during processing. Conversely, excessively high density of volumetric microdefects can exacerbate uneven thermal stress distribution, causing significant warping of the substrate during oxidation. In this embodiment, the target oxygen and nitrogen contents of the substrate are determined based on the target thickness of the oxide layer. This ensures that the size and density of volumetric microdefects in the substrate vary depending on the target oxide layer thickness, thereby enabling the volumetric microdefects to effectively resist slip line defects generated during subsequent oxidation processes.

[0042] In some embodiments, when the target thickness of the oxide layer is greater than 0 μm and less than 2 μm, the target oxygen content of the substrate is 6 new ppma to 10 new ppma, and the target nitrogen content of the substrate is 1 × 10⁻⁶. 13 atoms / cm 3 ~ 5×10 13 atoms / cm 3 .

[0043] In some embodiments, when the target thickness of the oxide layer is greater than or equal to 2 μm and less than or equal to 3 μm, the target oxygen content of the substrate is 10 new ppma to 14 new ppma, and the target nitrogen content of the substrate is 1 × 10⁻⁶. 14 atoms / cm 3 ~ 5×10 14 atoms / cm 3 .

[0044] In some embodiments, when the target thickness of the oxide layer is greater than 3 μm and less than or equal to 4 μm, the target oxygen content of the substrate is 14 new ppma to 18 new ppma, and the target nitrogen content of the substrate is 1 × 10⁻⁶. 15 atoms / cm 3 ~3×10 15 atoms / cm 3 .

[0045] Next, as Figure 2 As shown, step S3 is performed to provide a substrate 100 having the target oxygen content and the target nitrogen content, that is, the target oxygen content and the target nitrogen content of the substrate 100 are determined according to the target thickness of the oxide layer to be formed, and a substrate 100 having the corresponding target oxygen content and target nitrogen content is provided.

[0046] In this embodiment, the substrate 100 is made of silicon. Specifically, the method for forming the substrate 100 includes: first, providing a seed crystal, which is placed in a quartz crucible; then, performing a Czochralski process on the seed crystal to grow an ingot, the ingot being a silicon ingot, with the crystal growth direction being... <100> , <110> or <111> Next, the ingot is subjected to at least a slicing process, a grinding process, a polishing process, and a cleaning process in sequence to form the substrate 100. Among these processes, a nitrogen doping process is performed during the Czochralski process to adjust the nitrogen content of the substrate 100.

[0047] Furthermore, during the Czochralski process, crystal growth parameters are controlled to regulate the oxygen content of the final substrate 100. These parameters include rotational speed, pressure, magnetic field, and gas flow rate during ingot growth.

[0048] Next, step S4 is executed, and the oxidation temperature and oxidation time of the oxidation process are determined according to the target thickness. That is, the oxidation temperature and oxidation time of the subsequent oxidation process are adjusted accordingly based on the target thickness of the oxide layer 110 to avoid slip line defects caused by excessively high oxidation temperature and excessively long oxidation time.

[0049] In some embodiments, when the target thickness of the oxide layer 110 is greater than 0 μm and less than 2 μm, the oxidation temperature of the oxidation process (i.e., the oxidation temperature determined according to the target thickness of the substrate) is 950°C to 1050°C, and the oxidation time is 15 h to 20 h. The size of the bulk microdefects in the substrate 100 after the oxidation process is 50 nm to 60 nm, and the density of the bulk microdefects in the substrate 100 after the oxidation process is 5 × 10⁻⁶. 8 cm -3 ~7×10 8 cm -3 .

[0050] In some embodiments, when the target thickness of the oxide layer 110 is greater than or equal to 2 μm and less than or equal to 3 μm, the oxidation temperature of the oxidation process is 1050℃~1100℃, and the oxidation time is 20h~25h. The size of the bulk microdefects in the substrate 100 after the oxidation process is 70nm~80nm, and the density of the bulk microdefects in the substrate 100 after the oxidation process is 5×10⁻⁶. 9 cm-3 ~7×10 9 cm -3 .

[0051] In some embodiments, when the target thickness of the oxide layer 110 is greater than 3 μm and less than or equal to 4 μm, the oxidation temperature of the oxidation process is 1100℃~1200℃, and the oxidation time is 25h~30h. The size of the bulk microdefects in the substrate 100 after the oxidation process is 80nm~100nm, and the density of the bulk microdefects in the substrate 100 after the oxidation process is 1×10⁻⁶. 10 cm -3 ~3×10 10 cm -3 .

[0052] Next, as Figure 2 As shown, step S5 is performed, in which an oxidation process is performed on the substrate 100 according to the oxidation temperature and oxidation time of the oxidation process, so as to form an oxide layer 110 of the target thickness on the substrate 100.

[0053] Optionally, the substrate 100 may be cleaned before performing the oxidation process to remove impurities and other contaminants from the surface of the substrate 100.

[0054] During the oxidation process, the substrate 100 is first loaded into the furnace tube at a temperature of 500°C to 650°C. Then, in an argon (Ar) atmosphere, the temperature of the furnace tube is raised to 900°C to 950°C at a heating rate of 5°C / min to 7°C / min. Next, based on the target thickness of the oxide layer 110, the temperature of the furnace tube is raised to the oxidation temperature (950°C to 1200°C) at a heating rate of 2°C / min to 5°C / min, and oxygen is introduced into the furnace tube to form the oxide layer 110 on the surface of the substrate 100. The oxygen flow rate can be 5 SLM to 20 SLM, and the material of the oxide layer is silicon oxide.

[0055] Since the density of bulk microdefects (BMDs) in substrate 100 is approximately linearly positively correlated with the target oxygen content of the substrate, in this embodiment, the target oxygen content of the substrate is 6 new ppma to 10 new ppma, and the number of oxygen atoms in substrate 100 is relatively sufficient. During the oxidation process, the size of the bulk microdefects (BMDs) in substrate 100 increases with the increase of the target oxygen content of substrate 100.

[0056] Furthermore, the oxygen content of the substrate 100 varies depending on the target thickness of the oxide layer 110. Therefore, the ample oxygen content within the substrate 100 provides a sufficient source of material for the growth of oxygen precipitates, allowing for the accumulation of more oxygen atoms during the oxidation process, thus enabling continuous growth. During this process, the diffusion rate of oxygen atoms accelerates, allowing the oxygen precipitates formed in the substrate 100 to absorb surrounding oxygen atoms more quickly, resulting in a more significant increase in the size of bulk microdefects.

[0057] Since a substrate 100 with target oxygen and nitrogen content was selected based on the target thickness of the oxide layer 110 in the aforementioned steps, the substrate 100 maintains the target oxygen and nitrogen content during the oxidation process. This allows for the modification of the size and density of bulk microdefects in the substrate 100, effectively resisting slip line defects generated during the oxidation process. Simultaneously, the oxidation temperature and time are adjusted according to the target thickness of the oxide layer to avoid slip line defects caused by excessively high oxidation temperatures or prolonged oxidation times, thereby reducing or eliminating the problem of slip line defects appearing on the substrate during the oxidation process. Three embodiments and two comparative examples are provided below to further illustrate the effects of the substrate oxidation method provided in this embodiment.

[0058] Example 1, as Figure 2 As shown, a substrate 100 is provided, with a thickness of 775 μm, a target oxygen content of 9.25 new ppma, and a target nitrogen content of 3.12 × 10⁻⁶. 13 atoms / cm 3 Then, the substrate 100 is cleaned; next, the cleaned substrate 100 is loaded into a furnace tube and loaded at 600°C. In an argon (Ar) atmosphere, the temperature is increased to 950°C at a rate of 5°C / min, and then further increased to 1000°C at a rate of 2°C / min. At 1000°C, oxygen is introduced for oxidation at a flow rate of 10 SLM to form an oxide layer 110 on the substrate 100. The oxidation process takes 15 hours, resulting in an oxide layer 110 thickness of 1.8 μm. Next, the temperature is decreased to 950°C in an argon (Ar) atmosphere at a rate of 2°C / min, with an argon flow rate of 20 SLM. Then, the temperature is further decreased to 600°C at a rate of 5°C / min. After the oxidation process, the substrate 100 is subjected to film thickness and geometric parameter tests, as well as bulk microdefect tests. The bulk microdefect size (BMD) inside the substrate 100 is measured. The size is 55.6 nm, and the density of bulk microdefects (BMDDensity) is 6.23 × 10⁻⁶. 8 cm -3 .

[0059] Figure 4 This is a schematic scan of the front side of the substrate after the oxidation process is performed in Embodiment 1 of the substrate oxidation method provided by the present invention. Figure 5 This is a schematic scan of the back side of the substrate after the oxidation process, as shown in Embodiment 1 of the substrate oxidation method provided by the present invention. Figure 4 and Figure 5 As shown, after the oxidation process, substrate 100 is free of slip line defects.

[0060] Example 2, as Figure 2 As shown, a substrate 100 is provided, with a thickness of 775 μm, a target oxygen content of 17.45 new ppma, and a target nitrogen content of 2.55 × 10⁻⁶. 15 atoms / cm 3 Then, the substrate 100 is cleaned; next, the cleaned substrate 100 is placed into a furnace tube and heated to 600°C. The loading operation was performed at a specific temperature. The temperature was increased to 950°C in an argon (Ar) atmosphere at a rate of 5°C / min, and then further increased to 1200°C at a rate of 2°C / min. Oxygen was introduced at 1200°C to perform an oxidation process, forming an oxide layer 110 on the substrate 100. The oxygen flow rate was 10 SLM, and the oxidation process lasted 25 hours, resulting in an oxide layer 110 thickness of 4 μm. Next, the substrate was cooled to 950°C in an argon (Ar) atmosphere at a rate of 2°C / min, with an argon flow rate of 20 SLM. Then, the substrate was cooled to 600°C at a rate of 5°C / min. After the oxidation process, the substrate 100 was tested for film thickness and geometric parameters. The tests showed that the size of the bulk microdefects inside the substrate 100 was 95.7 nm, and the density of the bulk microdefects was 2.45 × 10⁻⁶. 10 cm -3 .

[0061] Figure 6 This is a schematic scan of the front side of the substrate after the oxidation process is performed in Embodiment 2 of the substrate oxidation method provided by the present invention. Figure 7 This is a schematic scan of the back side of the substrate after the oxidation process, in Embodiment 2 of the substrate oxidation method provided by the present invention. Figure 6 and Figure 7 As shown, after the oxidation process, substrate 100 is free of slip line defects.

[0062] Example 3, as Figure 2 As shown, a substrate 100 is provided, with a thickness of 775 μm, a target oxygen content of 12.64 new ppma, and a target nitrogen content of 4.35 × 10⁻⁶. 14atoms / cm 3 Then, the substrate 100 is cleaned; next, the cleaned substrate 100 is loaded into a furnace tube and loaded at 600°C. The temperature is then increased to 950°C in an argon (Ar) atmosphere at a rate of 5°C / min, with an argon gas flow rate of 20 SLM; then, the temperature is further increased to 1100°C at a rate of 2°C / min, and oxygen is introduced at 1100°C to perform an oxidation process, forming an oxide layer 110 on the substrate 100. The oxygen gas flow rate is 10 SLM, and the oxidation process takes 21 hours, resulting in an oxide layer 110 with a thickness of 2.8 mm. Next, in an argon (Ar) atmosphere, the substrate was cooled to 950°C at a rate of 2°C / min, with an argon gas flow rate of 20 SLM. Then, the substrate was further cooled to 600°C at a rate of 5°C / min. Afterwards, the substrate 100 after the oxidation process was tested for film thickness and geometric parameters, and BMD (bulk defect density) was performed. The tests showed that the size of the bulk microdefects inside the substrate 100 was 77.8 nm, and the bulk microdefect density was 6.37 × 10⁻⁶. 9 cm -3 .

[0063] Figure 8 This is a schematic scan of the front side of the substrate after the oxidation process is performed in Embodiment 3 of the substrate oxidation method provided by the present invention. Figure 9 This is a schematic scan of the back side of the substrate after the oxidation process, as shown in Embodiment 3 of the substrate oxidation method provided by the present invention. Figure 8 and Figure 9 As shown, after the oxidation process, substrate 100 is free of slip line defects.

[0064] Comparative Example 1, such as Figure 2 As shown, a substrate 100 is provided, with a thickness of 775 μm, a target oxygen content of 18.56 new ppma, and a target nitrogen content of 2.55 × 10⁻⁶. 15 atoms / cm 3Then, the substrate 100 is cleaned; next, the cleaned substrate 100 is placed into a furnace tube and heated to 600°C. The loading operation was performed at a specific temperature. The temperature was increased to 950°C in an argon (Ar) atmosphere at a rate of 5°C / min, with an argon gas flow rate of 20 SLM. Then, the temperature was increased to 1200°C at a rate of 2°C / min, and oxygen was introduced at 1200°C to perform an oxidation process, forming an oxide layer 110 on the substrate 100. The oxygen gas flow rate was 10 SLM, and the oxidation process lasted for 25 hours, resulting in an oxide layer 110 thickness of 4 μm. Next, the temperature was decreased to 950°C in an argon (Ar) atmosphere at a rate of 2°C / min. Then, the temperature was decreased to 600°C at a rate of 5°C / min, with an argon gas flow rate of 20 SLM. After the oxidation process, the substrate 100 was subjected to film thickness testing, geometric parameter testing, and bulk microdefect testing. The tests showed that the size of the bulk microdefects inside the substrate 100 was 110.57 nm, and the density of the bulk microdefects was 4.56 × 10⁻⁶. 10 cm -3 .

[0065] Figure 10 This is a schematic scan of the front side of the substrate after the oxidation process is performed, in Comparative Example 1 of the substrate oxidation method provided by the present invention. Figure 11 This is a schematic scan of the back side of the substrate after the oxidation process, in Comparative Example 1 of the substrate oxidation method provided by this invention. (See attached image.) Figure 10 and Figure 11 As shown, after the oxidation process, the surface of the substrate 100 has a slip line 100a, that is, a slip line defect appears in the substrate 100.

[0066] Comparative Example 2, such as Figure 2 As shown, a substrate 100 is provided, with a thickness of 775 μm, a target oxygen content of 19.52 new ppma, and a target nitrogen content of 2.55 × 10⁻⁶. 15 atoms / cm 3Then, the substrate 100 is cleaned; next, the cleaned substrate 100 is placed into a furnace tube and heated to 600°C. The loading operation was performed at a specific temperature. The temperature was increased to 950°C in an argon (Ar) atmosphere at a rate of 5°C / min, and then further increased to 1200°C at a rate of 2°C / min. At 1200°C, oxygen was introduced for oxidation to form an oxide layer 110 on the substrate 100. The oxygen flow rate was 10 SLM, and the oxidation process lasted 25 hours, resulting in an oxide layer 110 thickness of 4 μm. Next, the temperature was decreased to 950°C in an argon (Ar) atmosphere at a rate of 2°C / min, with an argon flow rate of 20 SLM. Then, the substrate was cooled to 600°C at a rate of 5°C / min. After the oxidation process, the substrate 100 was subjected to film thickness testing, geometric parameter testing (to check for slip line defects), and bulk microdefect testing. The tests showed that the size of the bulk microdefects inside the substrate 100 was 135.7 nm, and the density of the bulk microdefects was 2.21 × 10⁻⁶. 10 cm -3 .

[0067] Figure 12 This is a schematic scan of the front side of the substrate after the oxidation process is performed, in Comparative Example 2 of the substrate oxidation method provided by the present invention. Figure 13 This is a schematic scan of the back side of the substrate after the oxidation process, in Comparative Example 2 of the substrate oxidation method provided by this invention. (See attached image.) Figure 12 and Figure 13 As shown, after the oxidation process, the surface of the substrate 100 has a slip line 100a, that is, a slip line defect appears in the substrate 100.

[0068] Comparing the above three embodiments and two comparative examples, it can be seen that the substrate oxidation method provided in this embodiment (Embodiment 1, Embodiment 2 and Embodiment 3) results in smaller size and density of bulk micro-defects inside the substrate, and no slip line defects appear in the substrate, thereby avoiding the problem of slip line defects appearing in the substrate during the oxidation process.

[0069] This embodiment also provides a semiconductor device, such as Figure 2 As shown, the semiconductor device includes a substrate 100 and an oxide layer 110 located on the substrate. The oxide layer 110 is formed using the substrate oxidation method provided in this embodiment. The bulk microdefects in the substrate 100 have a size of 50 nm to 100 nm, and the bulk microdefect density of the substrate is 5 × 10⁻⁶. 8 cm -3 ~3×10 10 cm -3 .

[0070] Specifically, when the target thickness of the oxide layer 110 is greater than 0 μm and less than 2 μm, after the oxide layer 110 is formed by performing an oxidation process on the substrate 100, the size of the bulk micro-defects on the substrate is 50 nm to 60 nm, and the density of the bulk micro-defects on the substrate is 5 × 10⁻⁶. 8 cm -3 ~7×10 8 cm -3 Alternatively, when the target thickness of the oxide layer is greater than or equal to 2 μm and less than or equal to 3 μm, after the oxide layer 110 is formed by performing an oxidation process on the substrate 100, the size of the bulk micro-defects on the substrate is 70 nm to 80 nm, and the density of the bulk micro-defects on the substrate is 5 × 10⁻⁶. 9 cm -3 ~7×10 9 cm -3 Alternatively, when the target thickness of the oxide layer is greater than 3 μm and less than or equal to 4 μm, after the oxide layer 110 is formed by performing an oxidation process on the substrate 100, the size of the bulk micro-defects on the substrate is 80 nm to 100 nm, and the density of the bulk micro-defects on the substrate is 1 × 10⁻⁶. 10 cm -3 ~3×10 10 cm -3 .

[0071] In summary, in the substrate oxidation method and semiconductor device provided by this invention, the target thickness of the oxide layer to be formed is first determined, which is greater than 0 μm and less than or equal to 4 μm. Then, based on the target thickness of the oxide layer to be formed, the target oxygen content and target nitrogen content of the substrate are determined. The target oxygen content of the substrate is 6 new ppma to 18 new ppma, and the target nitrogen content of the substrate is 1 × 10⁻⁶. 13 atoms / cm 3 ~3×10 15 atoms / cm 3Next, a substrate with target oxygen and nitrogen contents is provided. Then, based on the target thickness of the oxide layer, the oxidation temperature and oxidation time of the oxidation process are determined. Next, based on the oxidation temperature and oxidation time, the substrate is subjected to an oxidation process to form an oxide layer of the target thickness. Thus, by determining the target oxygen and nitrogen contents of the substrate based on the target thickness of the oxide layer, and using a substrate with corresponding target oxygen and nitrogen contents to perform the oxidation process, the size and density of bulk micro-defects in the substrate corresponding to oxide layers of different target thicknesses are different, thereby enabling bulk micro-defects to effectively resist slip line defects generated during the oxidation process. Simultaneously, the oxidation temperature and oxidation time of the oxidation process are adjusted accordingly based on the target thickness of the oxide layer to avoid slip line defects caused by excessively high oxidation temperatures and excessively long oxidation times, thereby reducing or avoiding the problem of slip line defects in the substrate during the oxidation process.

[0072] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. In addition, different parts between embodiments can also be combined with each other, and this invention does not limit this.

[0073] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method for oxidizing a substrate, characterized in that, include: Determine the target thickness of the oxide layer to be formed, wherein the target thickness of the oxide layer is greater than 0 μm and less than or equal to 4 μm; Based on the target thickness, the target oxygen content and target nitrogen content of the substrate are determined. The target oxygen content of the substrate is 6 new ppma to 18 new ppma. Specifically, when the target thickness of the oxide layer is greater than 0 μm and less than 2 μm, the target oxygen content of the substrate is 6 new ppma to 10 new ppma; when the target thickness of the oxide layer is greater than or equal to 2 μm and less than or equal to 3 μm, the target oxygen content of the substrate is 10 new ppma to 14 new ppma; and when the target thickness of the oxide layer is greater than 3 μm and less than or equal to 4 μm, the target oxygen content of the substrate is 14 new ppma to 18 new ppma. The target nitrogen content of the substrate is 1 × 10⁻⁶. 13 atoms / cm 3 ~3×10 15 atoms / cm 3 ; A substrate having the target oxygen content and the target nitrogen content is provided; Based on the target thickness, determine the oxidation temperature and oxidation time for the oxidation process; An oxidation process is performed on the substrate according to the oxidation temperature and oxidation time of the oxidation process to form an oxide layer of the target thickness on the substrate.

2. The substrate oxidation method according to claim 1, characterized in that, When the target thickness of the oxide layer is greater than 0 μm and less than 2 μm, the target nitrogen content of the substrate is 1 × 10⁻⁶. 13 atoms / cm 3 ~ 5×10 13 atoms / cm 3 .

3. The substrate oxidation method according to claim 1, characterized in that, When the target thickness of the oxide layer is greater than or equal to 2 μm and less than or equal to 3 μm, the target nitrogen content of the substrate is 1 × 10⁻⁶. 14 atoms / cm 3 ~5×10 14 atoms / cm 3 .

4. The substrate oxidation method according to claim 1, characterized in that, When the target thickness of the oxide layer is greater than 3 μm and less than or equal to 4 μm, the target nitrogen content of the substrate is 1 × 10⁻⁶. 15 atoms / cm 3 ~3×10 15 atoms / cm 3 .

5. The substrate oxidation method according to claim 1, characterized in that, When the target thickness of the oxide layer is greater than 0 μm and less than 2 μm, the oxidation temperature of the oxidation process is 950℃~1050℃ and the oxidation time is 15h~20h.

6. The substrate oxidation method according to claim 1, characterized in that, When the target thickness of the oxide layer is greater than or equal to 2 μm and less than or equal to 3 μm, the oxidation temperature of the oxidation process is 1050℃~1100℃ and the oxidation time is 20h~25h.

7. The substrate oxidation method according to claim 1, characterized in that, When the target thickness of the oxide layer is greater than 3 μm and less than or equal to 4 μm, the oxidation temperature of the oxidation process is 1100℃~1200℃ and the oxidation time is 25h~30h.

8. A semiconductor device, characterized in that, include: A substrate and an oxide layer located on the substrate, the oxide layer being formed using the substrate oxidation method as described in any one of claims 1 to 7; The substrate has a bulk microdefect size of 50 nm to 100 nm and a bulk microdefect density of 5 × 10⁻⁶. 8 cm -3 ~3×10 10 cm -3 .

9. The semiconductor device as claimed in claim 8, characterized in that, When the target thickness of the oxide layer is greater than 0 μm and less than 2 μm, the size of the bulk microdefects in the substrate is 50 nm to 60 nm, and the density of the bulk microdefects in the substrate is 5 × 10⁻⁶. 8 cm -3 ~7×10 8 cm -3 Alternatively, when the target thickness of the oxide layer is greater than or equal to 2 μm and less than or equal to 3 μm, the size of the bulk microdefects in the substrate is 70 nm to 80 nm, and the density of the bulk microdefects in the substrate is 5 × 10⁻⁶. 9 cm -3 ~7×10 9 cm -3 Alternatively, when the target thickness of the oxide layer is greater than 3 μm and less than or equal to 4 μm, the size of the bulk microdefects in the substrate is 80 nm to 100 nm, and the density of the bulk microdefects in the substrate is 1 × 10⁻⁶. 10 cm -3 ~3×10 10 cm -3 .

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