Semiconductor device manufacturing method and semiconductor device sacrificial layer etching system
By using mixed corrosion liquid to convert liquid carbon dioxide into supercritical fluid carbon dioxide, the slow etching rate, structural damage and adhesion problems in the release of suspended structures of semiconductor devices are solved, and efficient structural corrosion and cleaning are achieved, which improves product yield and reduces costs.
Patent Information
- Application Number
- CN202510226373.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2025-07-11
AI Technical Summary
The prior art has problems of structural adhesion caused by slow etching rate, structural damage, etching contaminants and incomplete etching during the release of suspended structures of semiconductor devices.
The mixed corrosion liquid is used to premix the main corrosion reagent and liquid carbon dioxide and then converted into supercritical fluid carbon dioxide. It is used to etch the sacrificial layer of the suspended structure, and is adjusted with parameters such as temperature, pressure and time to achieve damage-free structural corrosion release and cleaning.
The damage-free structural corrosion release and cleaning is achieved, which reduces cost consumption, improves product yield, and reduces waste through reagent recycling.
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Figure CN120288703A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of semiconductor device manufacturing. Specifically, it relates to a semiconductor device manufacturing method and a semiconductor device sacrificial layer etching system. Background Art
[0002] In the semiconductor manufacturing process, as the critical dimension of the process continues to decrease, the device structure has a higher aspect ratio, and advanced processes are more sensitive to contaminants. The need for non-damaging processes and ultra-clean processes is more urgent. For some semiconductor devices, there are suspended structures (structures where most of the positions are spaced from other structures and are only connected to the underlying basic support structure by a single or one-sided fulcrum). It is necessary to etch the sacrificial layer under the suspended structure to release the suspended structure. Micro-pore contaminants after etching release and structural adhesion after corrosion release will all affect the performance and yield of semiconductor devices. The requirements for the release of product device structures and cleaning after release are getting higher and higher. Conventional release processes currently mainly have problems such as slow etching rate, structural damage, etching contaminants, and are prone to incomplete etching, adhesion between the suspended structure and the underlying layer, and failure to achieve the suspended effect.
[0003] Therefore, a solution is needed to solve the problems of slow etching rate, structural damage, etching contaminants, and structural adhesion caused by incomplete etching in the release of semiconductor device suspended structures. Summary of the Invention
[0004] Therefore, this application provides a semiconductor device manufacturing method and a semiconductor device sacrificial layer etching system to solve the problems of slow etching rate, structural damage, etching contaminants, and structural adhesion caused by incomplete etching in the release of suspended structures.
[0005] In one aspect of this application, a semiconductor device manufacturing method is provided, including a step of releasing a suspended structure. The step of releasing the suspended structure includes the following steps: providing a semiconductor substrate, the semiconductor substrate includes a substrate layer, a sacrificial layer on the surface of the substrate layer, a layer to be released on the surface of the sacrificial layer facing away from the substrate layer, and a connection layer provided on the same layer as the sacrificial layer and connecting the layer to be released and the substrate layer; etching the layer to be released to form a release hole; using a mixed etching solution, and through the release hole, corroding and removing the sacrificial layer; the mixed etching solution includes a main etching reagent and liquid carbon dioxide. Before the mixed etching solution enters the reaction vessel for removing the sacrificial layer, it is heated and pressurized to convert the liquid carbon dioxide into supercritical fluid carbon dioxide, and then enters the reaction vessel for removing the sacrificial layer for the removal operation.
[0006] The semiconductor device manufacturing method provided by this application pre-mixes liquid carbon dioxide with the main etching reagent, and then turns into supercritical fluid carbon dioxide after entering the reaction vessel. It is mixed with the main etching reagent to form a mixed etching solution, and they jointly etch the sacrificial layer. By utilizing the low viscosity and low surface tension of supercritical carbon dioxide, cleaning is carried out during etching, enabling damage-free structural corrosion release and cleaning. It can effectively prevent product defects caused by pollution residues after dry etching and structural adhesion and damage after wet etching, reduce cost consumption, and improve product yield. In addition, according to the requirements of different material release depths of actual device products, effective corrosion cleaning can be achieved by simply replacing the etching reagent and adjusting process parameters such as temperature, pressure, time, etc. It has low cost, a simple process, and reliable control.
[0007] Optionally, in some embodiments, when the sacrificial layer is silicon dioxide, the main etching reagent includes HF; when the sacrificial layer is silicon, the main etching reagent includes KOH; the volume ratio of the main etching reagent in the mixed etching solution is 1% - 40%.
[0008] In the semiconductor device manufacturing method provided by this application, if the volume ratio of the main etching reagent is less than 1%, it is difficult to achieve an effective etching effect, the etching rate is too slow, and the efficiency is low; if the volume ratio is greater than 40%, the etching rate is too fast, the supercritical effect is poor, and structural adhesion is likely to occur. Therefore, the volume ratio of the main etching reagent in the mixed etching solution is 1% - 40%, which can achieve a balance between effective etching and avoiding structural adhesion.
[0009] Optionally, in some embodiments, the mixed etching solution further includes: a solvent-type additive to make the etching effect uniform; the solvent-type additive is an alcohol, a ketone, or an ether that does not react with the main etching reagent and does not react with any layer of the semiconductor substrate; the solvent-type additive includes ethanol or isopropanol; the volume ratio of the solvent-type additive in the mixed etching solution is 5% - 30%.
[0010] The semiconductor device manufacturing method provided by this application adds a solvent-type auxiliary agent to the mixed etching solution. Since the solvent-type auxiliary agent does not react with any layer of the main etching reagent and the semiconductor substrate, and the solvent-type auxiliary agent can reduce the diffusion resistance on the solid-liquid surface and enhance the reaction adsorption activity, it can increase the etching uniformity and the etching selectivity ratio, so that uniform etching can be achieved. The uniform etching here means that the surface roughness after etching is small, smooth and clean, and the surface uniformity after etching is good, the plane is flat, and there is no phenomenon of ups and downs. In addition, the role of the solvent here also has the effect of enhancing cleaning, sweeping the organic particles on the surface, and preventing the organic matter from interfering with etching. If the volume ratio of the solvent-type auxiliary agent in the mixed etching solution is less than 5%, the dispersion effect is not obvious; when the proportion of the etching solution is certain, if the volume ratio in the mixed etching solution is greater than 30%, the effect of the low viscosity and low surface tension beyond the upper limit and supercritical state is not good, adhesion is easy to occur, and the etching rate is slow. Therefore, the volume ratio of the solvent-type auxiliary agent in the mixed etching solution is 5% - 30%, which can achieve a balance between effectively dispersing the main etching reagent and avoiding adhesion and achieving a better etching rate.
[0011] Optionally, in some embodiments, in the step of removing the sacrificial layer: the operating pressure is 50 MPa - 200 MPa; the operating temperature is 30 °C - 60 °C; the operating time is 5 min - 20 min; the flow rate of the mixed etching solution is 15 L / min - 40 L / min.
[0012] In the semiconductor device manufacturing method provided by this application, among the above operating conditions, if the upper and lower limits are exceeded, it is difficult for carbon dioxide to maintain the supercritical fluid state, and it becomes a liquid or a gas, and non-adhesive etching cannot be achieved.
[0013] Optionally, in some embodiments, the step of etching the layer to be released to form a release hole includes: forming a mask layer on the surface of the layer to be released on the side facing away from the sacrificial layer; using the mask layer as a mask to etch the layer to be released to form a release hole; then removing the mask layer; the mask layer is a silicon dioxide hard mask.
[0014] Optionally, in some embodiments, the semiconductor device manufacturing method further includes: after removing the sacrificial layer, depressurizing to separate carbon dioxide from the used mixed etching solution; recycling the separated carbon dioxide for reuse.
[0015] The semiconductor device manufacturing method provided by this application performs separation and recovery treatment on the used mixed etching solution, which can reuse the main etching reagent that has not been fully used and the carbon dioxide that does not participate in the reaction at all, realizes the recycling of the reagent, and reduces waste.
[0016] Optionally, in some embodiments, a condenser is used to re-condense the separated carbon dioxide gas into liquid carbon dioxide and re-introduce it for use.
[0017] Optionally, in some embodiments, in the step of removing the sacrificial layer, the reaction vessel is a stainless-steel sealed tank body; the stainless-steel sealed tank body includes at least one of a stirring structure, a vibration structure, and an ultrasonic generating structure.
[0018] The semiconductor device manufacturing method provided by the present application can improve the etching effect through a stirring structure, a vibration structure, an ultrasonic generating structure, etc.
[0019] Optionally, in some embodiments, the stainless-steel sealed tank body includes a plurality of spaced reaction units, and each reaction unit is adapted to simultaneously and separately accommodate different semiconductor substrates.
[0020] In the semiconductor device manufacturing method provided by the present application, the tank body includes a plurality of spaced reaction units, and batch processing can be performed.
[0021] In another aspect of the present application, a semiconductor device sacrificial layer etching system is provided, including: a reagent supply unit, the reagent supply unit includes a liquid carbon dioxide unit and a main etching reagent unit; a premixing unit, respectively communicating with the main etching reagent unit and the liquid carbon dioxide unit, and a reaction vessel, adapted to premix the liquid carbon dioxide and the main etching reagent before entering the reaction vessel; a reaction vessel, the reaction vessel includes a tank body, and a temperature control component and a pressure control component, adapted to convert the liquid carbon dioxide in the mixed etching solution of the liquid carbon dioxide and the main etching reagent introduced into the reaction vessel into supercritical fluid carbon dioxide through the temperature control component and the pressure control component.
[0022] The semiconductor device sacrificial layer etching system provided by the present application can be applied to the semiconductor device manufacturing method provided by the present application. By premixing the liquid carbon dioxide with the main etching reagent, and then converting it into supercritical fluid carbon dioxide after entering the reaction vessel, mixing with the main etching reagent to form a mixed etching solution, and jointly etching the sacrificial layer. Utilizing the low viscosity and low surface tension of supercritical carbon dioxide, cleaning is performed while etching, and non-destructive structural corrosion release and cleaning can be achieved. It can effectively prevent product defects caused by pollution residues after dry etching and structural adhesion and damage after wet etching, reduce cost consumption, and improve product yield. In addition, according to the requirements of different material release depths of actual device products, etc., effective corrosion cleaning can be achieved by simply replacing the etching reagent and adjusting process parameters such as temperature, pressure, time, etc. The cost is low, the process is simple, and the control is reliable.
[0023] Optionally, in some embodiments, the reaction vessel is a stainless-steel sealed tank body; the stainless-steel sealed tank body includes at least one of a stirring structure, a vibration structure, and an ultrasonic generating structure.
[0024] The sacrificial layer etching system for semiconductor devices provided by this application can improve the etching effect through a stirring structure, a vibration structure, an ultrasonic generating structure, etc.
[0025] Optionally, in some embodiments, the stainless-steel sealed tank body includes a plurality of spaced reaction units, and each reaction unit is adapted to simultaneously accommodate different semiconductor substrates respectively.
[0026] The sacrificial layer etching system for semiconductor devices provided by this application has a tank body including a plurality of spaced reaction units and can perform batch processing.
[0027] Optionally, in some embodiments, the sacrificial layer etching system for semiconductor devices further includes: a separation chamber, which is connected to the reaction vessel and has an incompletely isolated liquid layer and gas layer; a gas recovery chamber, which is connected to the gas layer of the separation chamber; a condenser is provided in the gas recovery chamber; a liquid recovery chamber, which is connected to the liquid layer of the separation chamber.
[0028] The sacrificial layer etching system for semiconductor devices provided by this application can, through the settings of the separation chamber, the gas recovery chamber and the liquid recovery chamber, realize the separation and recovery treatment of the used mixed etching solution, and can recover the main etching reagent that has not been completely used and the carbon dioxide that does not participate in the reaction at all for subsequent treatment steps, so as to perform safe discharge or re-use after treatment and purification. Brief Description of the Drawings
[0029] In order to more clearly illustrate the specific embodiments of this application or the technical solutions in the prior art, the following will briefly introduce the drawings required to be used in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0030] Figure 1 It is a schematic structural diagram after the sacrificial layer is etched by wet etching to release the suspended structure;
[0031] Figure 2 It is a schematic structural diagram after the sacrificial layer is etched by dry etching to release the suspended structure;
[0032] Figure 3 It is a schematic flow chart of the semiconductor device manufacturing method according to an embodiment of this application;
[0033] Figure 4 It is a schematic diagram after the sacrificial layer is etched in the semiconductor device manufacturing method according to an embodiment of this application to release the suspended structure;
[0034] Figure 5 It is the sacrificial layer etching system for semiconductor devices according to an embodiment of this application. Detailed Description of the Embodiments
[0035] As described in the background art, the conventional release process currently mainly has problems such as slow etching rate, structural damage, etching pollutants, etc., and is prone to incomplete etching, adhesion between the suspended structure and the lower part, and failure to achieve the suspended effect.
[0036] Specifically, as Figure 1 shown, a schematic structural diagram after wet etching the sacrificial layer to release the suspended structure. The etched semiconductor device includes: a substrate layer 100, a connection layer 220, and a suspended structure 300. In the release of wet etching, for example, the release of a silicon oxide structure usually uses an etching solution containing HF for etching. Due to surface tension, it is difficult to enter the deep structure during etching, and it is easy to have Figure 1 residue of the sacrificial layer 210 in Figure 2 shown, a schematic structural diagram after wet etching the sacrificial layer to release the suspended structure. The etched semiconductor device includes: a substrate layer 100, a connection layer 220, and a suspended structure 300. In the release of dry etching, for example, the release of a common silicon structure usually uses xenon fluoride gas, and its etching rate is relatively slow. Then, it is inevitable to perform long-term etching. With a long reaction time, the surface will be uneven and the uniformity will be poor (such as the uneven and non-uniform surface shown in Figure 2 ), and a large amount of etched residual pollutants will remain in the uneven pits and holes, which are difficult to clean and remove, ultimately resulting in a reduction in the device effect.
[0037] Therefore, the present application provides a method for manufacturing a semiconductor device and a sacrificial layer etching system for a semiconductor device to solve the problems of slow etching rate, structural damage, etching pollutants, and structural adhesion caused by incomplete etching in the release of the suspended structure.
[0038] The present application provides a method for manufacturing a semiconductor device, including a step of releasing a suspended structure. The step of releasing the suspended structure includes the following steps: providing a semiconductor substrate, the semiconductor substrate including a substrate layer, a sacrificial layer on the surface of the substrate layer, a layer to be released on the surface of the sacrificial layer facing away from the substrate layer, and a connection layer provided on the same layer as the sacrificial layer and connecting the layer to be released and the substrate layer; etching the layer to be released to form a release hole; using a mixed etching solution to etch and remove the sacrificial layer through the release hole; the mixed etching solution includes a main etching reagent and liquid carbon dioxide. Before the mixed etching solution enters the reaction vessel for removing the sacrificial layer, it is heated and pressurized to convert the liquid carbon dioxide into supercritical fluid carbon dioxide, and then enters the reaction vessel for removing the sacrificial layer to perform the removal operation.
[0039] In one aspect of the present application, the technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts fall within the scope of protection of the present application. In the description of the present application, it should be noted that the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.
[0040] In another aspect of the present application, a sacrificial layer etching system for semiconductor devices is provided, including: a reagent supply unit, which includes a liquid carbon dioxide unit and a main etching reagent unit; a premixing unit, which is respectively connected to the main etching reagent unit and the liquid carbon dioxide unit, and a reaction vessel, which is adapted to premix the liquid carbon dioxide and the main etching reagent before entering the reaction vessel; a reaction vessel, which includes a tank body, as well as a temperature control component and a pressure control component, and is adapted to convert the liquid carbon dioxide in the mixed etching solution of the liquid carbon dioxide and the main etching reagent introduced into the reaction vessel into supercritical fluid carbon dioxide through the temperature control component and the pressure control component.
[0041] Example 1
[0042] Reference Figure 3 , this example provides a method for manufacturing a semiconductor device, including a step of releasing a suspended structure. The step of releasing the suspended structure includes the following steps:
[0043] Provide a semiconductor substrate, which includes a substrate layer, a sacrificial layer located on the surface of the substrate layer, a layer to be released on the surface of the sacrificial layer facing away from the substrate layer, and a connection layer provided on the same layer as the sacrificial layer and connecting the layer to be released and the substrate layer;
[0044] Etch the layer to be released to form a release hole;
[0045] Use a mixed etching solution to corrode and remove the sacrificial layer through the release hole; the mixed etching solution includes a main etching reagent and liquid carbon dioxide. Before entering the reaction vessel for removing the sacrificial layer, the mixed etching solution is heated and pressurized to convert the liquid carbon dioxide into supercritical fluid carbon dioxide, and then enters the reaction vessel for removing the sacrificial layer for the removal operation.
[0046] The semiconductor device manufacturing method provided by this application pre-mixes liquid carbon dioxide with the main etching reagent, and then turns into supercritical fluid carbon dioxide after entering the reaction vessel. It is mixed with the main etching reagent to form a mixed etching solution, which jointly etches the sacrificial layer. By utilizing the low viscosity and low surface tension of supercritical carbon dioxide, cleaning is carried out during etching, enabling damage-free structural corrosion release and cleaning. It can effectively prevent product defects caused by pollution residues after dry etching and structural adhesion and damage after wet etching, reduce cost consumption, and improve product yield. In addition, according to the requirements of different material release depths of actual device products, effective corrosion cleaning can be achieved by simply replacing the etching reagent and adjusting process parameters such as temperature, pressure, time, etc. It has low cost, a simple process, and reliable control.
[0047] Using the semiconductor device manufacturing method provided by this application, the effect after the release of the suspended structure is as Figure 4 shown. The suspended structure 300 is connected to the substrate layer 100 through the connection layer 220. The sacrificial layer between the suspended structure 300 and the substrate layer 100 is completely removed, without residues as Figure 1 shown, nor does it have a pitted surface as Figure 2 shown.
[0048] Further, in some embodiments, when the sacrificial layer is silicon dioxide, the main etching reagent includes HF; when the sacrificial layer is silicon, the main etching reagent includes KOH; for example, 49% HF and 40% KOH. The volume ratio of the main etching reagent in the mixed etching solution is 1% - 40%.
[0049] In the semiconductor device manufacturing method provided by this application, if the volume ratio of the main etching reagent is less than 1%, it is difficult to achieve an effective etching effect, the etching rate is too slow, and the efficiency is low; if the volume ratio is greater than 40%, the etching rate is too fast, the supercritical effect is poor, and structural adhesion is likely to occur. Therefore, the volume ratio of the main etching reagent in the mixed etching solution is 1% - 40%, which can achieve a balance between effective etching and avoiding structural adhesion.
[0050] Further, in some embodiments, the mixed etching solution further includes: a solvent-based auxiliary agent to make the etching effect uniform; the solvent-based auxiliary agent is an alcohol, a ketone, or an ether that does not react with the main etching reagent and does not react with any layer of the semiconductor substrate; the solvent-based auxiliary agent includes ethanol or isopropanol; the volume ratio of the solvent-based auxiliary agent in the mixed etching solution is 5% - 30%.
[0051] The semiconductor device manufacturing method provided by this application adds a solvent-based auxiliary agent to the mixed etching solution. Since the solvent-based auxiliary agent does not react with any layer of the main etching reagent and the semiconductor substrate, and the solvent-based auxiliary agent can reduce the diffusion resistance on the solid-liquid surface and enhance the reaction adsorption activity, it can increase the etching uniformity and etching selectivity, so uniform etching can be achieved. The uniform etching here means that the surface roughness after etching is small, smooth and clean, and the surface uniformity after etching is good, the plane is flat, and there is no phenomenon of undulation. In addition, the solvent also plays a role in enhancing cleaning, sweeping the organic particles on the surface to prevent the organic matter from interfering with etching. If the volume ratio of the solvent-based auxiliary agent in the mixed etching solution is less than 5%, the dispersion effect is not obvious; when the proportion of the etching solution is fixed, if the volume ratio in the mixed etching solution is greater than 30%, the effect of the supercritical low viscosity and low surface tension beyond the upper limit is not good, adhesion is likely to occur, and the etching rate is slow. Therefore, when the volume ratio of the solvent-based auxiliary agent in the mixed etching solution is 5% - 30%, a balance can be achieved between effectively dispersing the main etching reagent and avoiding adhesion and achieving a better etching rate.
[0052] Further, in some embodiments, in the step of removing the sacrificial layer: the operating pressure is 50 MPa - 200 MPa; the operating temperature is 30 °C - 60 °C; the operating time is 5 min - 20 min; the flow rate of the mixed etching solution is 15 L / min - 40 L / min. It should be noted that the operating temperature and operating pressure here are the pressure and temperature in the reaction chamber, that is, the pressure and temperature required to maintain the supercritical fluid.
[0053] In the semiconductor device manufacturing method provided by this application, under the above operating conditions, if the upper and lower limits are exceeded, it is difficult for carbon dioxide to maintain the state of supercritical fluid, and it becomes a liquid or a gas, and non-adhesive etching cannot be achieved.
[0054] Further, in some embodiments, the step of etching the layer to be released to form release holes includes: forming a mask layer on the surface of the layer to be released on the side facing away from the sacrificial layer; using the mask layer as a mask to etch the layer to be released to form release holes; then removing the mask layer; the mask layer is a silicon dioxide hard mask, which has a relatively good etching selectivity relative to silicon. When etching silicon, the silicon dioxide is basically not affected and can maintain a complete structural form.
[0055] Further, in some embodiments, the semiconductor device manufacturing method further includes: after removing the sacrificial layer, releasing the pressure to separate carbon dioxide from the used mixed etching solution; recycling the separated carbon dioxide and putting it back into use.
[0056] The semiconductor device manufacturing method provided by this application separates and recycles the used mixed etching solution, enabling the reuse of the main etching reagent that has not been fully used and the carbon dioxide that does not participate in the reaction at all, realizing the recycling of the reagent and reducing waste.
[0057] Further, in some embodiments, a condenser is used to condense and recover the remaining unreacted main etching reagent. The recovered mixed solution can be post-treated as needed to achieve safe discharge or separated and purified for reuse. The post-treatment after recovery is carried out in another system, and those skilled in the art can choose according to needs.
[0058] Further, in some embodiments, for the step of removing the sacrificial layer, the reaction vessel is a stainless steel sealed tank body; the stainless steel sealed tank body includes at least one of a stirring structure, a vibration structure, and an ultrasonic generating structure.
[0059] The semiconductor device manufacturing method provided by this application can improve the etching effect through structures such as a stirring structure, a vibration structure, and an ultrasonic generating structure.
[0060] Further, in some embodiments, the stainless steel sealed tank body includes a plurality of spaced reaction units, and each reaction unit is adapted to simultaneously accommodate different semiconductor substrates respectively.
[0061] The semiconductor device manufacturing method provided by this application has a tank body including a plurality of spaced reaction units and can perform batch processing.
[0062] Example 2
[0063] This embodiment provides a semiconductor device sacrificial layer etching system, refer to Figure 5 , including:
[0064] A reagent supply unit, which includes a liquid carbon dioxide unit 1 and a main etching reagent unit 2;
[0065] A premixing unit 4, which is respectively connected to the main etching reagent unit 2, the liquid carbon dioxide unit 1, and the reaction vessel 5. It is adapted to premix the liquid carbon dioxide and the main etching reagent before entering the reaction vessel;
[0066] A reaction vessel 5, which includes a tank body, as well as a temperature control component and a pressure control component, and is adapted to convert the liquid carbon dioxide in the mixed etching solution of the liquid carbon dioxide and the main etching reagent introduced into the reaction vessel into supercritical fluid carbon dioxide through the temperature control component and the pressure control component.
[0067] The sacrificial layer etching system for semiconductor devices provided by this application is applicable to the semiconductor device manufacturing method provided by this application. By premixing liquid carbon dioxide with the main etching reagent and then entering the reaction vessel to be transformed into supercritical fluid carbon dioxide, which is mixed with the main etching reagent to form a mixed etching solution, the etching of the sacrificial layer is carried out together. Utilizing the low viscosity and low surface tension of supercritical carbon dioxide, cleaning is carried out during etching, enabling damage-free structural corrosion release and cleaning. It can effectively prevent product defects caused by pollution residues after dry etching and structural adhesion and damage after wet etching, reduce cost consumption, and improve product yield. In addition, according to the requirements of different material release depths of actual device products, effective etching and cleaning can be achieved by simply replacing the etching reagent and adjusting process parameters such as temperature, pressure, time, etc. It has low cost, a simple process, and reliable control.
[0068] Further, in some embodiments, the reagent supply unit further includes an auxiliary agent 3 for accommodating and providing a solvent-based auxiliary agent. Each reagent supply unit is respectively connected to the premixing unit 4 through pipelines, and valves are respectively arranged on the pipelines to control the flow rate respectively and regulate the ratio of the premixed solution.
[0069] Further, a transfer pump 9 is arranged on the pipeline between the premixing unit and the reaction vessel 5 to pump the premixed mixed etching solution in the premixing unit 4 into the reaction vessel 5.
[0070] Further, in some embodiments, the reaction vessel 5 is a stainless steel sealed tank body; the stainless steel sealed tank body includes at least one of a stirring structure, a vibration structure, and an ultrasonic generating structure.
[0071] The sacrificial layer etching system for semiconductor devices provided by this application can improve the etching effect through a stirring structure, a vibration structure, an ultrasonic generating structure, etc.
[0072] Further, in some embodiments, the stainless steel sealed tank body includes a plurality of spaced reaction units, and each reaction unit is adapted to simultaneously accommodate different semiconductor substrates respectively.
[0073] The sacrificial layer etching system for semiconductor devices provided by this application, the tank body includes a plurality of spaced reaction units, and batch processing can be carried out.
[0074] Further, continue to refer to Figure 5 , in some embodiments, the sacrificial layer etching system for semiconductor devices further includes:
[0075] A separation chamber 6, the separation chamber 6 is connected to the reaction vessel 5 and has an incompletely isolated liquid layer and gas layer;
[0076] A gas recovery chamber 7, which is connected to the gas layer of the separation chamber 6; a condenser is arranged in the gas recovery chamber 7;
[0077] The liquid recovery chamber 8 is in communication with the liquid layer of the separation chamber 6.
[0078] Figure 5 The solid line in the figure is the reaction pipeline, and the dotted line is the direction of reusing after post-treatment. A pressure relief valve 10 is provided on the pipeline between the separation chamber and the reaction vessel 5. After etching, the mixed etching solution is depressurized and enters the separation chamber 6. In a low-pressure environment, supercritical carbon dioxide returns to a gas and naturally separates from the mixed solution, enters the gas layer, and then enters the gas recovery chamber 7. Then, post-treatment can be carried out for discharge, or pressurization and other treatments can be carried out to re-become liquid carbon dioxide and then enter the liquid carbon dioxide unit 1 for reuse. The remaining liquid part in the mixed etching solution enters the liquid layer. At the same time, the mixed solution carried out by the carbon dioxide gas escaped from the gas layer is re-condensed into liquid droplets and enters the liquid layer through the un-isolated part of the gas layer and the liquid layer, and enters the liquid recovery chamber 8 together with other liquids. Then, post-treatment can be carried out for discharge, or other separation and purification treatments can be carried out and then re-invested into the premixing unit 4 for reuse.
[0079] The sacrificial layer etching system for semiconductor devices provided by this application can realize the separation and recovery treatment of the used mixed etching solution through the settings of the separation chamber, the gas recovery chamber, and the liquid recovery chamber, and can recover the main etching reagent that is not fully used and the carbon dioxide that does not participate in the reaction at all for subsequent treatment steps, so as to carry out safe discharge or treatment and purification and then reuse.
[0080] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of this application.
Claims
1. A method for manufacturing a semiconductor device, including a step of releasing a suspended structure, characterized in that, The step of releasing the suspended structure includes the following steps: Providing a semiconductor substrate, the semiconductor substrate includes a substrate layer, a sacrificial layer located on the surface of the substrate layer, a layer to be released on the surface of the sacrificial layer facing away from the substrate layer, and a connection layer provided in the same layer as the sacrificial layer, connecting the layer to be released and the substrate layer; Etching the layer to be released to form a release hole; Using a mixed etching solution to etch and remove the sacrificial layer through the release hole; The mixed etching solution includes a main etching reagent and liquid carbon dioxide. Before entering the reaction vessel for removing the sacrificial layer, the mixed etching solution is heated and pressurized to convert the liquid carbon dioxide into supercritical fluid carbon dioxide, and then enters the reaction vessel for removing the sacrificial layer for the removal operation.
2. The method for manufacturing a semiconductor device according to claim 1, wherein When the sacrificial layer is silicon dioxide, the main etching reagent includes HF; When the sacrificial layer is silicon, the main etching reagent includes KOH; The volume ratio of the main etching reagent in the mixed etching solution is 1% - 40%.
3. The method for manufacturing a semiconductor device according to claim 2, wherein The mixed etching solution further includes: a solvent-based auxiliary agent to make the etching effect uniform; The solvent-based auxiliary agent is an alcohol, a ketone or an ether that does not react with the main etching reagent and does not react with any layer of the semiconductor substrate; The solvent-based auxiliary agent includes ethanol or isopropanol; The volume ratio of the solvent-based auxiliary agent in the mixed etching solution is 5% - 30%.
4. The method for manufacturing a semiconductor device according to claim 1, wherein In the step of removing the sacrificial layer: The operating pressure is 50 MPa - 200 MPa; The operating temperature is 30°C - 60°C; The operating time is 5 min - 20 min; The flow rate of the mixed etching solution is 15 L / min - 40 L / min.
5. The method for manufacturing a semiconductor device according to claim 1, wherein The step of etching the layer to be released to form a release hole includes: Forming a mask layer on the surface of the layer to be released on the side facing away from the sacrificial layer; Using the mask layer as a mask to etch the layer to be released to form the release hole; Then removing the mask layer; The mask layer is a silicon dioxide hard mask.
6. The method for manufacturing a semiconductor device according to claim 1, wherein, It further includes: After removing the sacrificial layer, depressurizing to separate carbon dioxide from the used mixed etching solution; Recycling the separated carbon dioxide for reuse.
7. The method for manufacturing a semiconductor device according to claim 6, wherein Using a condenser to condense and recover the remaining unreacted main etching reagent.
8. The method for manufacturing a semiconductor device according to claim 1, wherein In the step of removing the sacrificial layer, the reaction vessel is a stainless steel sealed tank body; The stainless steel sealed tank body includes at least one of a stirring structure, a vibration structure, and an ultrasonic generating structure.
9. The method for manufacturing a semiconductor device according to claim 8, wherein The stainless steel sealed tank body includes a plurality of spaced reaction units, and each reaction unit is adapted to simultaneously accommodate different semiconductor substrates respectively.
10. A sacrificial layer etching system for a semiconductor device, characterized in that, Comprising: A reagent supply unit, the reagent supply unit includes a liquid carbon dioxide unit and a main corrosion reagent unit; A premixing unit, which is respectively connected to the main corrosion reagent unit and the liquid carbon dioxide unit, and a reaction vessel, and is adapted to premix the liquid carbon dioxide and the main corrosion reagent before entering the reaction vessel; A reaction vessel, the reaction vessel includes a tank body, and a temperature control component and a pressure control component, and is adapted to convert the liquid carbon dioxide in the mixed corrosion liquid of the liquid carbon dioxide and the main corrosion reagent introduced into the reaction vessel into supercritical fluid carbon dioxide through the temperature control component and the pressure control component.
11. The semiconductor device sacrificial layer etching system according to claim 10, wherein The reaction vessel is a stainless steel sealed tank body; The stainless steel sealed tank body includes at least one of a stirring structure, a vibration structure, and an ultrasonic generating structure.
12. The semiconductor device sacrificial layer etching system according to claim 11, wherein The stainless steel sealed tank body includes a plurality of spaced reaction units, and each reaction unit is adapted to simultaneously accommodate different semiconductor substrates respectively.
13. The semiconductor device sacrificial layer etching system according to claim 10, characterized in that Further comprising: A separation chamber, the separation chamber is connected to the reaction vessel and has an incompletely isolated liquid layer and gas layer; A gas recovery chamber, which is connected to the gas layer of the separation chamber; a condenser is provided in the gas recovery chamber; A liquid recovery chamber, which is connected to the liquid layer of the separation chamber.