Process method of groove structure and semiconductor process equipment
By using ultraviolet light-assisted oxidation and high-temperature annealing, the resistance and thermal management problems caused by sidewall roughness in trench MOSFET devices were solved, thereby improving device stability and production capacity.
Patent Information
- Application Number
- CN202511794019.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-01
- Publication Date
- 2026-03-03
AI Technical Summary
In existing technologies, excessive roughness of the trench sidewalls during the fabrication of trench MOSFET devices leads to increased channel resistance, higher system power consumption, and difficulties in thermal management. Furthermore, the high-temperature oxidation process is time-consuming, impacting production capacity.
The process employs ultraviolet light-assisted oxidation, in which H2O2 is introduced at room temperature and the ultraviolet light source is turned on. The power of the light source and the gas flow rate are gradually increased to form an oxide sacrificial layer. This layer is then removed to reduce the sidewall roughness, and the morphology is improved by combining it with high-temperature annealing.
It can effectively oxidize and etch the damaged layer at room temperature, reduce the roughness of the trench structure sidewall, reduce the channel resistance, reduce system power consumption, improve device stability, shorten process time, and increase production capacity.
Smart Images
Figure CN121604745A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor technology, and more specifically, to a process method and semiconductor process equipment for a trench structure. Background Technology
[0002] The most critical performance indicators for power devices include voltage withstand capability, switching speed, and stability. Among these, stability places extremely high demands on thermal management and power loss, especially for automotive-grade chips, where stability requirements are more than five times higher than those for conventional consumer-grade chips. Process damage is a key factor affecting stability; therefore, eliminating process damage is crucial in the manufacturing process of power devices.
[0003] In trench MOSFET devices, the MOS conductive channels are formed in the trench sidewalls. The roughness of the trench sidewalls affects the electron mobility of the trench MOSFET device. Excessive roughness of the trench sidewalls leads to increased channel resistance, increased system power consumption, and difficulties in thermal management. However, in the related processes of trench MOSFET devices, only dry etching methods are generally used to obtain U-shaped trenches. The sidewalls of the trenches are relatively rough, sometimes even exhibiting a striation structure, making it difficult to achieve ideal smoothness, resulting in poor device stability. Summary of the Invention
[0004] The purpose of this invention is to provide a process method and semiconductor process equipment for trench structures, so as to improve the technical problem of poor stability of MOSFET devices in related technologies.
[0005] The manufacturing process for the trench structure provided by this invention includes: A step is provided to provide a trench structure, the surface of which has an etched damage layer; In the oxidation step, the process temperature is set to 20~40 ℃, H2O2 is introduced, the ultraviolet light source is turned on, and the power of the ultraviolet light source is gradually increased from the initial power to the termination power, so that the etched damage layer is transformed into an oxide sacrificial layer; wherein, the initial power is 500~1000 W, and the termination power is 1600~2000 W; The removal step involves removing the oxide sacrificial layer.
[0006] Preferably, as one possible implementation, the oxidation step further includes: The flow rate of H2O2 is gradually increased from the initial flow rate to the final flow rate, and the process pressure is gradually increased from the initial pressure to the final pressure; wherein the initial flow rate is 500~750 sccm, the final flow rate is 750~5000 sccm, the initial pressure is 200~300 mTorr, and the final pressure is 300~2000 mTorr.
[0007] Preferably, as one possible implementation, in the oxidation step, The power of the ultraviolet light source increases uniformly at a constant rate from beginning to end; or, the ultraviolet light source operates at the initial power for a preset time, and then increases uniformly at a constant rate to the termination power. And / or, the flow rate of H2O2 increases uniformly at a constant rate from beginning to end; or, after H2O2 is introduced at the initial flow rate for a preset time, it increases uniformly at a constant rate to the termination flow rate. And / or, the process pressure increases uniformly at a constant rate from beginning to end; or, the process pressure is maintained at the initial pressure for a preset time, and then increases uniformly at a constant rate to the termination pressure.
[0008] Preferably, as one possible implementation, the process time of the oxidation step is 5 to 50 minutes; And / or, the thickness of the oxide sacrificial layer is 10~15 nm.
[0009] Preferably, as one possible implementation, before the oxidation step, the method further includes: a pre-aeration step, in which the process temperature is set to 20~40 ℃, the process pressure is set to the initial pressure, H2O2 is introduced at the initial flow rate, and the process duration is 5~50 s; And / or, after the oxidation step, the method further includes: a gas exchange step, setting the process temperature to 20~40 ℃, setting the process pressure to 200~500 mTorr, introducing an inert gas, and the process duration to 5~50 s; wherein the flow rate of the inert gas is 50~5000 sccm.
[0010] Preferably, as one possible implementation, after the removal step, the method further includes: In the annealing step, the process temperature is set to 1000~2000 ℃, argon gas is introduced, and annealing is carried out.
[0011] Preferably, as one possible implementation, in the annealing step, The argon flow rate is 10~10000 sccm, and / or the process pressure is 0.5~720 Torr, and / or the heating rate is 5~500 ℃ / min, and / or the process duration is 10 s~120 min.
[0012] Preferably, as one possible implementation, the annealing step further includes: A hydrogen-containing gas is introduced, the flow rate of which is 100~10000 sccm; wherein the hydrogen-containing gas includes CH4, NH3, PH3, H2S, H2O, HF, HCl or HBr.
[0013] Preferably, as one possible implementation, the removal step includes: introducing an acidic solution or an alkaline solution to remove the oxide sacrificial layer; wherein the acidic solution includes concentrated nitric acid or an HF solution with a concentration of less than 2%, and the alkaline solution includes concentrated NaOH solution or concentrated ammonia.
[0014] Preferably, as one possible implementation, the providing step includes: Provide silicon carbide matrix; HBr, SF6, and O2 are introduced, the process pressure is set to 1~20 mTorr, the upper electrode power is set to 500~3000W, the lower electrode power is set to 100~1000W, and the chuck temperature is set to -15~100 ℃ to perform dry etching on the silicon carbide substrate to form the trench structure; wherein, the proportion of HBr in the etching gas is 50~150%, and the flow ratio of SF6 to O2 is 10~1000%.
[0015] The semiconductor process equipment provided by the present invention includes a process chamber, an inlet assembly, an upper electrode assembly, a lower electrode assembly, and a controller. The controller is characterized in that it includes at least one processor and at least one memory, wherein the memory stores a computer program, and the computer program is executed by the processor to implement the above-described trench structure process method.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In this invention, during the oxidation treatment of the trench structure surface, H2O2 is introduced and an ultraviolet light source is turned on. The ultraviolet light photocatalyzes the H2O2 to generate OH and O radicals. These radicals react with the etched damage layer to form an oxide sacrificial layer. The power of the ultraviolet light source is controlled using a ramp method, increasing from 500-1000 W to 1600-2000 W. On the one hand, setting the UV light source to a lower power in the initial stage of the oxidation process can prevent the free radicals originally intended for oxidation from etching the trench structure due to excessive power of the UV light source, thus ensuring the oxidation effect on the etched damage area. On the other hand, as the oxidation process progresses, the power of the UV light source is gradually increased to provide more photons, increase the number of chemical bond breaks in H2O2, increase the free radical concentration, accelerate the deep oxidation rate of the etched damage layer, and prevent the formation of a dense oxide layer in the shallow layer of the etched damage layer that hinders the penetration of free radicals. This allows the deep parts of the etched damage layer to smoothly contact free radicals, reducing the oxidation difficulty, solving the rate self-limitation of room temperature oxidation, and improving the oxidation efficiency. This allows the etched damage layer to be basically completely oxidized to form an oxide sacrificial layer. Therefore, after removing the oxide sacrificial layer, the roughness of the trench structure sidewall can be greatly reduced, achieving ideal smoothness. This, in turn, can reduce channel resistance, reduce system power consumption and thermal management difficulty, maintain interface state stability, and thus optimize device stability.
[0017] It should be noted that the process method provided by the present invention uses ultraviolet-assisted oxidation to treat the etched damage layer on the surface of the trench structure and controls the ultraviolet light source to gradually increase, which can achieve effective oxidation of almost all etched damage layers at room temperature, greatly reducing the temperature of the oxidation process, and the process time is much shorter than the process time required for high-temperature oxidation heating and cooling, resulting in higher production capacity.
[0018] The semiconductor process equipment provided by this invention has the same technical features as the above-mentioned trench structure process method, so it can also solve the same technical problems and achieve the same technical effects. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0020] Figure 1 A first schematic flowchart of the manufacturing process for the trench structure provided in an embodiment of the present invention; Figure 2a and Figure 2bThis is a partial morphology diagram of the oxide sacrificial layer on the surface of the trench structure in an embodiment of the present invention; Figure 3 This is a partial morphology diagram of the trench structure in an embodiment of the present invention after the oxide sacrificial layer has been removed; Figure 4 A second schematic flowchart of the manufacturing process for the trench structure provided in an embodiment of the present invention; Figures 5a-5e A process flow diagram of the manufacturing method for the trench structure provided in an embodiment of the present invention; Figures 6a-6d These are morphological images of the groove structure in the embodiments of the present invention after annealing at different process temperatures; Figures 7a-7c These are partial morphological images of the sidewalls of the groove structure in the embodiments of the present invention after annealing at different process temperatures. Figures 8a-8c The image shows the surface roughness of the sidewalls of the groove structure in this embodiment of the invention after annealing at different process temperatures. Figure 9 This is a schematic diagram of the structure of a semiconductor process equipment provided in an embodiment of the present invention. Detailed Implementation
[0021] One related technique involves obtaining SiC trenches via dry etching, then oxidizing the sidewall damage layer of the SiC trench at high temperature to form a SiO2 sacrificial layer. The SiO2 sacrificial layer is then removed using a wet process to reduce the roughness of the trench sidewalls, making them as smooth as possible to ensure device stability. However, this method requires extremely high temperatures and has a long processing time, impacting production capacity. In addition, the bottom corners of U-shaped trenches obtained by dry etching are generally close to right angles or even acute angles, which can lead to electric field concentration at the bottom corners, making the devices prone to premature breakdown and failure.
[0022] Related technology two involves annealing to correct the anomalous microtrench structure formed at the bottom after silicon carbide etching under the following conditions: hydrogen atmosphere, chamber pressure 0.25 × 10⁻⁶. 5 Pa, annealing time 30~3600 s, annealing temperature 1400~1600℃. Although the bottom microgrooves are eliminated after annealing, the surface is too smooth, which makes too much of a change to the original structure and has no practical value.
[0023] The third related technology employs a two-step annealing process to optimize the morphology of silicon carbide trenches. The first step involves an annealing atmosphere of silane (0.09%) and argon, with a chamber pressure of 80 Torr, an annealing time of 600 s, and an annealing temperature of 1700 ℃. The second step uses a hydrogen atmosphere, with a chamber pressure of 80 Torr, an annealing time of 600 s, and an annealing temperature of 1500 ℃. This annealing process is relatively complex.
[0024] The technical solution of the present invention 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 the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0025] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.
[0026] Figure 1 A schematic flowchart of a process for fabricating a trench structure according to an embodiment of the present invention is provided, the method comprising: S102, providing a step, providing a trench structure, the surface of the trench structure having an etched damage layer; S104, Oxidation Step: Set the process temperature to 20~40 ℃, introduce H2O2, turn on the ultraviolet light source, and gradually increase the power of the ultraviolet light source from the initial power to the termination power to transform the etched damage layer into an oxide sacrificial layer; wherein, the initial power is 500~1000 W, and the termination power is 1600~2000 W. S106, Removal step, removing the oxide sacrificial layer.
[0027] In this embodiment, during the oxidation treatment of the trench structure surface, H2O2 is introduced and an ultraviolet light source is turned on. Ultraviolet photocatalysis of H2O2 generates OH and O radicals. These radicals react with the etched damage layer to form an oxide sacrificial layer. The ultraviolet light source is controlled using a ramp method, with its power gradually increased from 500-1000 W to 1600-2000 W. On the one hand, setting the ultraviolet light source to a lower power (500-1000 W) in the initial stage of the oxidation process prevents the free radicals intended for oxidation from etching the trench structure due to excessive power, ensuring effective oxidation at the etched damage areas. On the other hand, as the oxidation process progresses, the power of the ultraviolet light source is gradually increased to a higher power (1600-2000 W). W) provides more photons, increases the number of chemical bonds broken in H2O2, improves the concentration of free radicals, accelerates the deep oxidation rate of the etched damage layer, and prevents the formation of a dense oxide layer in the shallow layer of the etched damage layer that hinders the penetration of free radicals. This allows the deeper parts of the etched damage layer to smoothly contact free radicals, reduces the oxidation difficulty, solves the rate self-limitation of room temperature oxidation, improves oxidation efficiency, and enables the etched damage layer to be basically completely oxidized to form an oxide sacrificial layer (such as...). Figure 2a and Figure 2bAs shown in the figure, after removing the oxide sacrificial layer, the roughness of the trench structure sidewall can be greatly reduced, and ideal smoothness can be obtained. In turn, the channel resistance can be reduced, the system power consumption and thermal management difficulty can be reduced, and the interface state can be kept stable, thereby optimizing the device stability.
[0028] It should be noted that the process method provided in this embodiment uses ultraviolet-assisted oxidation to treat the etched damage layer on the surface of the trench structure and controls the ultraviolet light source to gradually increase. It can basically achieve effective oxidation of all etched damage layers at room temperature (20~40 ℃), which greatly reduces the temperature of the oxidation process. Moreover, the process time is much shorter than the process time required for high-temperature oxidation heating and cooling, resulting in higher production capacity.
[0029] Specifically, the initial power of the ultraviolet light source can be selected from 600~900 W, and further from 700~800 W; the final power of the ultraviolet light source can be selected from 1700~1900 W, and further from 1750~1800 W. The ultraviolet light source can be an excimer laser or a mercury lamp. The process temperature of the oxidation step can be selected from 25~35 ℃, and further from 28~32 ℃.
[0030] Step S104 further includes: increasing the H2O2 flow rate from the initial flow rate to the final flow rate, and increasing the process pressure from the initial pressure to the final pressure; wherein the initial flow rate is 500~750 sccm, the final flow rate is 750~5000 sccm, the initial pressure is 200~300 mTorr, and the final pressure is 300~2000 mTorr. In other words, while controlling the increase in ultraviolet light source power, the process pressure is controlled to increase from 200~300 mTorr to 300~2000 mTorr, and the H2O2 gas flow rate is controlled to increase from 500~750 sccm to 750~5000 sccm. This ensures sufficient free radicals, and the light intensity and free radicals increase synchronously, achieving a deeper room-temperature oxidation effect.
[0031] Specifically, the initial flow rate of H2O2 can be selected as 550~700 sccm, and further selected as 600~650 sccm; the final flow rate of H2O2 can be selected as 1000~4000 sccm, and further selected as 2000~3000 sccm. The initial pressure can be selected as 220~280 mTorr, and further selected as 240~260 mTorr; the final pressure can be selected as 600~1700 mTorr, further selected as 800~1500 mTorr, and even further selected as 1000~1200 mTorr.
[0032] In step S104 above, one can either choose to control the power of the ultraviolet light source to increase uniformly at a constant rate from beginning to end, or choose to control the ultraviolet light source to work at the initial power for a preset time, and then increase uniformly at a constant rate to the termination power. Both methods can achieve good process stability.
[0033] In step S104 above, it is possible to either control the flow rate of H2O2 to increase uniformly at a constant rate from beginning to end, or to control the flow rate of H2O2 to be introduced at an initial flow rate for a preset time, and then increase it uniformly at a constant rate until the termination flow rate. Both methods can achieve good process stability.
[0034] In step S104 above, it is possible to either control the process pressure to increase uniformly at a constant rate from beginning to end, or to control the process pressure to maintain the initial pressure for a preset time and then increase it uniformly at a constant rate to the termination pressure. Both methods can achieve good process stability.
[0035] The preset time can be half of the total process time of the oxidation step.
[0036] The oxidation step can be set to a process time of 5-50 minutes to meet the oxidation requirements of the etched damage layer on most trench structure surfaces. This process time is much shorter than the several hours of heating and cooling required to achieve the same oxidation effect at high temperatures. The preferred oxidation step process time is 10-40 minutes, more preferably 20-30 minutes. Specifically, the oxidation step process time can be determined based on the actual thickness of the etched damage layer; the greater the thickness, the longer the oxidation step process time.
[0037] The preferred combination of process parameters for the oxidation step is as follows: the ultraviolet light source is increased from 600 W to 1600 W, the H2O2 flow rate is increased from 500 sccm to 1000 sccm, the process pressure is increased from 200 mTorr to 500 mTorr, the process temperature is 20 ℃, and the process duration is 1200 s.
[0038] The thickness of the oxide sacrificial layer can be set to 10~15 nm to meet the removal requirements of etching damage layers on most trench structure surfaces. The thickness of the oxide sacrificial layer can be selected as 11~14 nm, and further selected as 12~13 nm.
[0039] Before step S104 above, the method provided in this embodiment may further include: a pre-ventilation step, setting the process temperature to 20~40 ℃, setting the process pressure to the aforementioned initial pressure, introducing H2O2 at the aforementioned initial flow rate, and a process duration of 5~50 s (preferably 10~40 s, more preferably 15~30 s, and even more preferably 20~25 s). In practice, the process temperature of the pre-ventilation step is consistent with the process temperature of the oxidation step. After the pre-ventilation step is completed, maintaining the process temperature, process pressure, and gas flow rate unchanged, and continuing to execute the oxidation step, can ensure the smoothness of the process transition and the stability of the process. The preferred combination of process parameters for the aforementioned pre-ventilation step is: ultraviolet light source power of 0, H2O2 flow rate of 500 sccm, process pressure of 200 mTorr, process temperature of 20 ℃, and process duration of 20 s.
[0040] Following step S104 above, the method provided in this embodiment may further include: a gas exchange step, setting the process temperature to 20~40 ℃, setting the process pressure to 200~500 mTorr, introducing an inert gas, and the process duration to 5~50 s; wherein the flow rate of the inert gas is 50~5000 sccm. The gas exchange step can clear the H2O2 in the process chamber, which is beneficial to ensuring the subsequent high-temperature annealing effect. Specifically, the inert gas can be argon, nitrogen, etc.; the process pressure can be selected as 300~400 mTorr; the flow rate of the inert gas is preferably 200~3000 sccm, more preferably 500~2000 sccm; the process duration is preferably 10~40 s, more preferably 20~30 s. The preferred combination of process parameters for the above-mentioned ventilation step is as follows: the power of the ultraviolet light source is 0, the flow rate of the inert gas is 500 sccm, the process pressure is 200 mTorr, the process temperature is 20 ℃, and the process duration is 20 s.
[0041] Following step S106 above, the method provided in this embodiment may further include an annealing step, setting the process temperature to 1000~2000 ℃, introducing argon gas, and performing annealing. High-temperature argon atmosphere annealing is beneficial for improving the trench morphology. It can transform the bottom and top corners of the trench structure from near right angles after etching to rounded corners after annealing. The sidewalls and bottom are essentially free of sharp angles. Simultaneously, the etching texture of the sidewalls tends to be smoother, and the surface roughness is reduced. This ensures that the breakdown voltage remains unchanged while reducing the risk of charge accumulation in the device and lowering the on-resistance.
[0042] In the above annealing step, the argon flow rate can be set to 10~10000 sccm, the process pressure to 0.5~720 Torr, the heating rate to 5~500 ℃ / min, and the process time to 10 s~120 min. Under these parameter conditions, better annealing effect can be obtained.
[0043] Optionally, during the annealing step, a hydrogen-containing gas can be introduced, with a flow rate of 100~10000 sccm; the hydrogen-containing gas can be any one of CH4, NH3, PH3, H2S, H2O, HF, HCl, and HBr. The presence of the hydrogen-containing gas can improve the sidewall smoothness of the trench structure; promote the migration and recombination of silicon atoms on the surface, repair lattice defects; and provide passivation protection, preventing the trench structure from being oxidized during annealing.
[0044] After high-temperature annealing, the inner wall of the groove structure can form a smooth surface, and the slope of the sidewall of the groove structure ranges from 78° to 88°; specifically, the slope of the upper half of the sidewall of the groove structure ranges from 82° to 88° (e.g., Figure 5e As shown in angle 1), the slope of the lower half of the sidewall of the trench structure ranges from 78° to 82° (as shown in angle 1). Figure 5e As shown in angle 2, it can be regarded as a double-angle sidewall, which is conducive to achieving a smooth transition between the sidewall and bottom wall of the trench structure.
[0045] In step S106 above, an acidic or alkaline solution can be introduced to remove the oxide sacrificial layer. The acidic or alkaline solution reacts with the oxide sacrificial layer (e.g., a silicon oxide layer) to achieve wet removal of the oxide sacrificial layer. The acidic solution can be concentrated nitric acid or an HF solution with a concentration below 2%; the alkaline solution can be concentrated NaOH or concentrated ammonia. After the oxide sacrificial layer is removed, the morphology of the trench structure is as follows... Figure 3 As shown.
[0046] Step S102 above includes: providing a silicon carbide substrate; introducing HBr, SF6, and O2, setting the process pressure to 1~20 mTorr, the upper electrode power to 500~3000 W, the lower electrode power to 100~1000 W, and the chuck temperature to -15~100 ℃, and performing dry etching on the silicon carbide substrate to form a trench structure; wherein, the proportion of HBr in the etching gas is 50~150%, and the flow ratio of SF6 to O2 is 10~1000%. The preferred combination of process parameters in the dry etching process is: process pressure of 10 mTorr, upper electrode power of 1000 W, lower electrode power of 350 W, SF6 flow rate of 15 sccm, O2 flow rate of 15 sccm, HBr flow rate of 90 sccm, process temperature of 40 ℃, and process duration of 270 s.
[0047] In fact, before dry etching the silicon carbide substrate using the above method, the silicon carbide substrate is first photolithographically developed to form trench patterns.
[0048] After dry etching of the silicon carbide substrate is completed, ion implantation can be performed on the trench structure to form a P-type base region. Then, the above step S104 is performed.
[0049] Figure 4 A schematic flowchart of a process for fabricating a trench structure according to an embodiment of the present invention is provided, the method comprising: S202, photolithography is performed on the silicon carbide substrate to form a trench pattern, resulting in... Figure 5a The structure shown; S204, through dry etching, undergoes anisotropic etching to form trenches with a high aspect ratio, resulting in... Figure 5b The structure shown; S206 is subjected to ion implantation to modify the material and form a P-type base region; S208, using a UV-assisted oxidation process, transforms the etch-damaged layer on the surface of the silicon carbide trench into a silicon oxide sacrificial layer, resulting in... Figure 5c The structure shown; S210, using an HF solution of less than 2%, removes the silicon oxide sacrificial layer on the surface, yielding... Figure 5d The structure shown; S212, under an argon atmosphere, undergoes high-temperature annealing to obtain the following... Figure 5e The structure shown.
[0050] The annealing step in the technical solution of the present invention will be described in detail below through specific embodiments.
[0051] Comparative Example The trench structure was not annealed, and its morphology is as follows: Figure 6a As shown, the bottom corner curvature of the trench structure is ≤0.1 μm; the sidewall morphology is as follows. Figure 7a As shown, the sidewall roughness characterization results of the trench structure are as follows: Figure 8a As shown, the sidewall roughness Rq is 5.172 nm and Ra is 4.050 nm.
[0052] Example 1 Argon gas was introduced, the process temperature was set to 1400 ℃, the process pressure was set to 200 Torr, and annealing was carried out for 40 min; the flow rate of argon gas was 2500 sccm.
[0053] After annealing, the morphology of the groove structure is as follows: Figure 6b As shown, the bottom corner curvature of the trench structure is 0.1~0.2 μm; the sidewall morphology is as follows. Figure 7b As shown, the sidewall roughness characterization results are as follows: Figure 8b As shown, the sidewall roughness Rq is 5.076 nm and Ra is 3.802 nm.
[0054] Example 2 Argon gas was introduced, the process temperature was set to 1500 ℃, the process pressure was set to 200 Torr, and annealing was carried out for 5 min; the flow rate of argon gas was 2500 sccm.
[0055] After annealing, the morphology of the groove structure is as follows: Figure 6c As shown, the bottom corner curvature of the trench structure is 0.2~0.3 μm; the sidewall morphology is as follows. Figure 7c As shown, the sidewall roughness characterization results are as follows: Figure 8c As shown, the sidewall roughness Rq is 4.572 nm and Ra is 3.312 nm.
[0056] Example 3 Argon gas was introduced, the process temperature was set to 1700 ℃, the process pressure was set to 200 Torr, and annealing was carried out for 2 min; the argon gas flow rate was 2500 sccm.
[0057] After annealing, the morphology of the groove structure is as follows: Figure 6d As shown, the bottom corner curvature of the trench structure is 0.2~0.5 μm.
[0058] Depend on Figure 6d It is known that annealing at 1700 ℃ for 2 min already exhibits over-correction. Therefore, the annealing time can be further shortened to be shorter than the shortest annealing time (60 s) at relatively low temperatures in related technologies. For example, annealing at 1700 ℃ for 30 s can be selected. In addition, the annealing time can be further shortened by increasing the process temperature. For example, annealing at 1800 ℃ for 10 s can be selected.
[0059] Depend on Figures 6a-6d It is known that high-temperature argon atmosphere annealing is beneficial to improving the morphology of the trench, transforming the near-right angles of the bottom and top corners of the trench from etched angles to rounded corners after annealing. Furthermore, as the annealing temperature increases, the radii of curvature of the bottom and top corners of the trench structure increase, while the length of the vertical section of the sidewall decreases. Figures 7a-7c as well as Figures 8a-8c It can be seen that high-temperature argon atmosphere annealing is beneficial to making the etching texture of the sidewalls smoother and reducing the surface roughness; on this basis, as the annealing temperature increases, the etching texture of the sidewalls tends to be smoother and the roughness decreases slightly.
[0060] Figure 9 A semiconductor process apparatus provided in one embodiment of the present invention includes a process chamber 20, an inlet assembly 20A, an upper electrode assembly 20B, a lower electrode assembly 20C, and a controller. Figure 9(Not shown in the diagram). The controller includes at least one processor and at least one memory, in which a computer program is stored, which, when executed by the processor, implements the method of any of the above embodiments.
[0061] For example, the controller can be a host computer or a slave computer. The controller can open the valve of the air inlet assembly 20A to introduce the corresponding process gas into the process chamber 20; the controller can also control the flow rate of the process gas by controlling the opening and closing degree of the valve of the air inlet assembly 20A. The controller can also control the evacuation assembly 20D to evacuate the process chamber 20, thereby controlling the gas pressure inside the process chamber 20 and removing reaction byproducts.
[0062] The upper electrode assembly 20B includes an RF coil 21, an upper RF power supply 23, and an upper matching unit 25. The controller is also used to control the upper RF power supply 23 to provide upper electrode power to the RF coil 21 through the upper matching unit 25, so that the RF coil 21 excites the process gas inside the process chamber 20 to generate plasma.
[0063] The lower electrode assembly 20C includes a wafer carrier 22, a lower RF power supply 24, and a lower matching unit 26. The controller further controls the lower RF power supply 24 to provide lower electrode power to the lower electrode of the wafer carrier 22 through the lower matching unit 26, thereby providing an RF bias voltage to the lower electrode of the wafer carrier 22 to attract plasma above the substrate and bombard the substrate. The wafer carrier 22 includes an electrostatic chuck.
[0064] The semiconductor process equipment in this application embodiment can be either an inductively coupled plasma (ICP) etching apparatus or a capacitively coupled plasma (CCP) etching apparatus. This application embodiment does not limit the type of semiconductor process equipment.
[0065] The semiconductor process equipment provided in this embodiment of the invention has the same technical features as the trench structure process method provided in the above embodiment, so it can also solve the same technical problems and achieve the same technical effects.
[0066] This embodiment also provides a machine-readable storage medium storing machine-executable instructions. When the machine-executable instructions are called and executed by a processor, the machine-executable instructions cause the processor to implement the above-described trench structure process.
[0067] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described equipment and apparatus can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.
[0068] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0069] In the description of this invention, it should be noted that the terms "upper," "lower," and "inner," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A manufacturing method for a trench structure, characterized in that, The method includes: A step is provided to provide a trench structure, the surface of which has an etched damage layer; In the oxidation step, the process temperature is set to 20~40 ℃, H2O2 is introduced, the ultraviolet light source is turned on, and the power of the ultraviolet light source is gradually increased from the initial power to the termination power, so that the etched damage layer is transformed into an oxide sacrificial layer; wherein, the initial power is 500~1000 W, and the termination power is 1600~2000 W; The removal step involves removing the oxide sacrificial layer.
2. The process method for the trench structure according to claim 1, characterized in that, The oxidation step further includes: The flow rate of H2O2 is increased from the initial flow rate to the final flow rate, and the process pressure is increased from the initial pressure to the final pressure; wherein the initial flow rate is 500~750 sccm, the final flow rate is 750~5000 sccm, the initial pressure is 200~300 mTorr, and the final pressure is 300~2000 mTorr.
3. The process method for the trench structure according to claim 2, characterized in that, In the oxidation step The power of the ultraviolet light source increases uniformly at a constant rate from beginning to end; or, the ultraviolet light source operates at the initial power for a preset time, and then increases uniformly at a constant rate to the termination power. And / or, the flow rate of H2O2 increases uniformly at a constant rate from beginning to end; or, after H2O2 is introduced at the initial flow rate for a preset time, it increases uniformly at a constant rate to the termination flow rate. And / or, the process pressure increases uniformly at a constant rate from beginning to end; Alternatively, the process pressure may be maintained at the initial pressure for a preset time, and then uniformly increased at a constant rate to the termination pressure.
4. The process method for the trench structure according to claim 1, characterized in that, The oxidation step has a process time of 5 to 50 minutes; And / or, the thickness of the oxide sacrificial layer is 10~15 nm.
5. The process method for the trench structure according to claim 2, characterized in that, Before the oxidation step, the method further includes: a pre-aeration step, in which the process temperature is set to 20~40 ℃, the process pressure is set to the initial pressure, H2O2 is introduced at the initial flow rate, and the process duration is 5~50 s; And / or, after the oxidation step, the method further includes: a gas exchange step, setting the process temperature to 20~40 ℃, setting the process pressure to 200~500 mTorr, introducing an inert gas, and the process duration to 5~50 s; wherein the flow rate of the inert gas is 50~5000 sccm.
6. The process method for the trench structure according to any one of claims 1-5, characterized in that, After the removal step, the method further includes: In the annealing step, the process temperature is set to 1000~2000 ℃, argon gas is introduced, and annealing is carried out.
7. The process method for the trench structure according to claim 6, characterized in that, In the annealing step The argon flow rate is 10~10000 sccm, and / or the process pressure is 0.5~720 Torr, and / or the heating rate is 5~500 ℃ / min, and / or the process duration is 10 s~120 min.
8. The process method for the trench structure according to claim 6, characterized in that, The annealing step also includes: A hydrogen-containing gas is introduced, the flow rate of which is 100~10000 sccm; wherein the hydrogen-containing gas includes CH4, NH3, PH3, H2S, H2O, HF, HCl or HBr.
9. The process method for the trench structure according to any one of claims 1-5, characterized in that, The removal step includes: introducing an acidic solution or an alkaline solution to remove the oxide sacrificial layer; wherein the acidic solution includes concentrated nitric acid or an HF solution with a concentration of less than 2%, and the alkaline solution includes concentrated NaOH solution or concentrated ammonia.
10. The process method for the trench structure according to any one of claims 1-5, characterized in that, The providing step includes: Provide silicon carbide matrix; HBr, SF6, and O2 are introduced, the process pressure is set to 1~20 mTorr, the upper electrode power is set to 500~3000 W, the lower electrode power is set to 100~1000 W, and the chuck temperature is set to -15~100 ℃ to perform dry etching on the silicon carbide substrate to form the trench structure; wherein, the proportion of HBr in the etching gas is 50~150%, and the flow ratio of SF6 to O2 is 10~1000%.
11. A semiconductor process apparatus, comprising a process chamber, an inlet assembly, an upper electrode assembly, a lower electrode assembly, and a controller, characterized in that, The controller includes at least one processor and at least one memory, the memory storing a computer program that, when executed by the processor, implements the process method for the trench structure as described in any one of claims 1-10.