CN115148643A - Wet etching equipment and wet etching method - Google Patents
Wet etching equipment and wet etching method Download PDFInfo
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- CN115148643A CN115148643A CN202210938351.1A CN202210938351A CN115148643A CN 115148643 A CN115148643 A CN 115148643A CN 202210938351 A CN202210938351 A CN 202210938351A CN 115148643 A CN115148643 A CN 115148643A
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Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67017—Apparatus for fluid treatment
- H01L21/67063—Apparatus for fluid treatment for etching
- H01L21/67075—Apparatus for fluid treatment for etching for wet etching
- H01L21/67086—Apparatus for fluid treatment for etching for wet etching with the semiconductor substrates being dipped in baths or vessels
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31105—Etching inorganic layers
- H01L21/31111—Etching inorganic layers by chemical means
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- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Weting (AREA)
Abstract
The invention provides wet etching equipment and a wet etching method, the wet etching equipment comprises an etching chamber and an adsorption module, one end of the adsorption module is communicated with a liquid outlet of the etching chamber and/or the adsorption module is arranged in the etching chamber, the etching chamber is used for wet etching of silicon oxide, silicon or silicon nitride on a substrate, the adsorption module is provided with an adsorption substance for adsorbing an etching product silicon compound, etching liquid in the etching process of the silicon oxide, silicon or silicon nitride material in the etching chamber flows through the adsorption module, and the etching product silicon compound is adsorbed and removed by the adsorption module, so that the regeneration of the etching liquid is realized. According to the wet etching equipment, the adsorption module capable of adsorbing the silicon compound is arranged on the circulating path of the etching solution, so that the service life of the etching solution can be effectively prolonged, the use cost is reduced, the environmental pollution caused by the discharge of the waste liquid of the etching solution is reduced, the frequency of replacing the etching solution is reduced, and the production efficiency is improved.
Description
Technical Field
The invention relates to the technical field of semiconductor manufacturing, in particular to a wet etching technology, and especially relates to wet etching equipment and a wet etching method.
Background
Integrated circuits are the foundation of the information industry, and integrated circuit fabrication is an important part of the integrated circuit industry. In semiconductor manufacturing, wet etching is a common process for removing dielectric materials such as silicon, silicon oxide, or silicon nitride compounds on a substrate. The mechanism of corrosion of silicon and/or inorganic compound materials thereof on the substrate in the etching solution is greatly different, so that the service life of the etching solution is influenced by multiple factors. Among them, the increase of the concentration of the etching products in the etching solution is one of the most important factors affecting the service life of the etching solution. How to remove the etching products in the etching solution, prolong the service life of the etching solution, reduce the cost, save the resources and improve the production efficiency is an important subject. One of the etching products of silicon and/or its inorganic compound material on the substrate in the etching solution is a compound containing silicon element, which is hereinafter referred to as a silicon compound. The invention absorbs the etching product silicon compound on the absorbing substance through the action of the absorbing substance and the etching product silicon compound so as to achieve the aim of removing the etching product silicon compound, effectively prolong the service life of the etching solution to reduce the cost and reduce the operation of replacing the etching solution to improve the production efficiency.
Taking wet etching of silicon nitride as an example, the wet etching of silicon nitride is usually performed by etching with an etching solution containing phosphoric acid, and the chemical reaction equation occurs as follows:
3Si 3 N 4 +4H 3 PO 4 +36H 2 O＝4(NH 4 ) 3 PO 4 +9Si(OH) 4 ，
wherein, phosphoric acid mainly plays a catalytic role, the consumption is less, and the main substance component reacting with silicon nitride is water. With the progress of the silicon nitride etching reaction, the etching product of silicon nitride in the phosphoric acid etching solution is silicon compound Si (OH) 4 The content rises when Si (OH) 4 When the concentration is increased to exceed a certain solubility, the etching reaction of silicon nitride may be gradually stopped and silicon oxide particles may be formed on the substrate, which may lead to the productThe yield of the process is greatly affected.
Taking wet etching of silicon oxide film as an example, the commonly used etching solution is diluted hydrofluoric acid solution (DHF) or buffered oxide etching solution (BOE), in which the basic chemical reaction equation is as follows:
SiO 2 +6HF＝H 2 SiF 6 +3H 2 O
taking the wet etching of silicon as an example, the isotropic wet etching of silicon is performed by using a mixed solution of nitric acid, hydrofluoric acid and water, and the basic chemical equation is as follows:
Si+HNO 3 +6HF＝H 2 SiF 6 +HNO 2 +H 2 O+H 2 ↑
anisotropic wet etching of silicon uses alkali species such as KOH, where the basic chemical reaction equation is as follows:
Si+4H 2 O＝Si(OH) 4 +2H 2 ↑
the etching products contain silicon compounds, and all the silicon compounds enter the etching solution along with the progress of the etching reaction. As the etching process of silicon and/or its inorganic compound material in the etching solution proceeds, the content of the silicon compound in the etching solution gradually increases, and when the content of the silicon compound increases to a certain concentration, the silicon compound may precipitate, which affects the etching effect.
In view of the above problems, there is no effective solution to replace the fresh etching solution partially or completely to reduce the concentration of silicon compounds in the etching solution, and then the next batch of substrates can be processed. Therefore, the service life of the etching solution is short, the consumption is large, resources are wasted, the cost is high, the production efficiency is low, and the environment pollution is caused by the discharge of a large amount of waste liquid.
Although efforts have been made to remove the silicon compound, which is an etching product in the etching solution, to maximize the life of the etching solution, the existence of the silicon compound in the etching solution is complicated, and the treatment method of heating the etching solution and adding the solution to react with the etching solution is inefficient, and thus the silicon compound cannot be effectively removed. The invention utilizes the adsorption module to adsorb, and the efficiency is obviously improved.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a wet etching apparatus and a wet etching method, which are used to solve the problems in the prior art that, when performing a wet etching process of silicon and/or inorganic compound materials thereof on a substrate, it is difficult to effectively remove silicon compounds, which are etching products in an etching solution, by adding water and heating liquid, and the like, so that the etching solution cannot be recycled, and only the etching solution can be frequently replaced, which results in short service life and large usage amount of the etching solution, and thus increases production cost, reduces production efficiency, and causes environmental pollution.
In order to achieve the above and other related objects, the present invention provides a wet etching apparatus, which includes an etching chamber and an adsorption module, wherein one end of the adsorption module is communicated with a liquid outlet of the etching chamber and/or the adsorption module is disposed in the etching chamber; the etching chamber accommodates a substrate to be processed and an etching solution, and the etching solution is in contact with the substrate to etch a material on the substrate and generate an etching product silicon compound, wherein the material on the substrate comprises any one of silicon, silicon oxide and silicon nitride; the adsorption module is provided with an adsorbent, etching liquid in the etching chamber enters the adsorption module, and etching product silicon compounds are removed by the adsorbent in the adsorption module.
Optionally, the adsorbent comprises one or more of ion exchange resin, alumina, zirconia, titania, silica and organosilicon compound, or a modified substance of surface groups of any one or more of the adsorbents, wherein the group modification is performed by one or more of fluorine group, sulfonic acid group, carboxyl group, cyclohexyl group, trimethyl aminopropyl group, benzene sulfonic acid propyl group, ethylenediamine-N-propyl group and surface groups of the adsorbents.
Optionally, the adsorbent comprises silicon, silicon carbide, a silicic acid polymer, a hydroxyl group-containing polymer, a carboxyl group-containing polymer, and a fluorine-based modifying material of any one or more of the foregoing adsorbents.
Optionally, the adsorption module further comprises a filtration unit, by which the adsorbent is prevented from flowing out of the adsorption module.
Optionally, the wet etching apparatus further comprises a monitoring module for detecting the concentration of the silicon compound.
Optionally, the wet etching apparatus further comprises a regeneration module of the adsorbent.
Optionally, the wet etching apparatus further comprises one or more of a circulation line, a pump, a filter, a heater, a heat exchanger, a liquid replenishing module, and an automatic control module.
The invention also provides a wet etching method, which comprises the following steps:
step S1, exposing one or a combination of silicon, silicon oxide or silicon nitride materials on a substrate to an etching solution for etching process to generate an etching product silicon compound;
step S2: and adsorbing a silicon compound by using an adsorbent, and separating the adsorbent from the etching solution to realize the cyclic utilization of the etching solution.
Optionally, the etching solution includes one or more of a phosphoric acid-containing solution, a hydrofluoric acid-containing solution, a tetramethylammonium hydroxide-containing solution, a potassium hydroxide-containing solution, and a sodium hydroxide-containing solution.
Optionally, the adsorbent comprises one or more of ion exchange resin, alumina, zirconia, titania, silica and organosilicon compound, or a modified substance of surface groups of any one or more of the adsorbents, wherein the group modification is performed by one or more of sulfonic acid group, carboxyl group, cyclohexyl group, trimethyl aminopropyl group, benzenesulfonic acid propyl group, ethylenediamine-N-propyl group and surface groups of the adsorbents.
Optionally, the adsorbent comprises silicon, silicon carbide, silicic acid polymers, hydroxyl group-containing polymers, carboxyl group-containing polymers, and fluorine surface modifying materials of any one or more of the foregoing adsorbents.
Optionally, the method for separating the adsorbent from the etching solution comprises one or more of filtering, cooling and precipitating.
Optionally, the method comprises adjusting the adsorption of the silicon compound on the surface of the adsorbent to adjust the concentration of the silicon compound in the etching solution, wherein the adjusting method comprises one or a combination of adjusting the temperature of the etching solution, adjusting the concentration of the etching solution and adjusting the temperature of the adsorbent.
Optionally, step S2 further includes adding an adsorption accelerator, where the adsorption accelerator includes one or a combination of water, hydrofluoric acid, ammonium fluoride and ammonium bifluoride.
As described above, the wet etching apparatus and the wet etching method provided by the present invention have the following beneficial effects: according to the wet etching equipment and the wet etching method, the adsorption module capable of adsorbing the silicon compound is arranged on the circulating path of the etching solution, so that the concentration of the etching product silicon compound in the etching solution can be effectively reduced, the service life of the etching solution is prolonged, the use cost is reduced, the environmental pollution caused by the discharge of waste liquid of the etching solution is reduced, the frequency of replacing the etching solution can be reduced, and the production efficiency is improved. The wet etching method provided by the invention is beneficial to improving the etching efficiency and reducing the etching cost.
Drawings
Fig. 1 to 3 are schematic structural diagrams illustrating a wet etching apparatus according to various embodiments of the present invention.
FIG. 4 is a schematic diagram of a monolithic etching chamber according to the present invention.
Fig. 5 illustrates a process flow diagram of the wet etching method of the present invention.
Description of the element reference numerals
11. Circulation pipeline
12. Adsorption module
13. Pump and method of operating the same
14. Filter
15. Heating device
16. Valve gate
17. Liquid supplementing module
20. Etching chamber
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. As in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the device structures are not partially enlarged in general scale for convenience of illustration, and the schematic views are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.
For convenience in description, spatial relational terms such as "below," "beneath," "below," "under," "over," "upper," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatial relationship terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.
In the context of this application, a structure described as a first feature being "on" a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.
It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated. In order to keep the drawings as compact as possible, not all structures are labeled in the figures.
The invention provides wet etching equipment, which comprises an etching chamber and an adsorption module, wherein one end of the adsorption module is communicated with a liquid outlet of the etching chamber and/or the adsorption module is arranged in the etching chamber; the etching chamber accommodates a substrate to be processed and an etching solution, and the etching solution is in contact with the substrate to etch a material on the substrate and generate an etching product silicon compound, wherein the material on the substrate comprises any one or combination of silicon, silicon oxide and silicon nitride; the adsorption module is provided with an adsorbent, etching liquid in the etching chamber enters the adsorption module, and etching product silicon compounds are removed by the adsorbent in the adsorption module.
It should be noted that the materials to be etched, i.e., silicon oxide and silicon nitride, may be silicon, silicon oxide and silicon nitride in a general sense, or may be the above materials doped with some elements.
It should be noted that the etching product silicon compound is generally a compound dissolved in the etching solution. If the silicon compound is not dissolved in the etching solution, for example, the concentration of the silicon compound exceeds the solubility in the etching solution to form insoluble substances, the insoluble substances can be removed by a filter, and the etching product in a dissolved form can be removed by an adsorption module. Therefore, the etching product in the invention, which is dissolved or not dissolved in the etching solution, can be removed by the adsorption module.
Next, in this specification, the wet etching apparatus and method of the present invention will be described with emphasis on the silicon nitride etching apparatus and method as an example, but the kind and application of the wet etching apparatus and method are not limited thereto.
Specifically, as shown in fig. 1, the present invention provides a wet etching apparatus, which includes an etching chamber 20 and an adsorption module 12, wherein one end of the adsorption module 12 is communicated with a liquid discharge port of the etching chamber 20. In this embodiment, the adsorption module 12 is located outside the etching chamber 20, and in other examples, the adsorption module 12 may also be located inside the etching chamber 20, or a part of the adsorption module 12 is located inside the etching chamber 20 and a part of the adsorption module is located outside the etching chamber 20. In this embodiment, the etching chamber 20 is illustrated as being used for wet etching of a silicon nitride material on a substrate, the adsorption module 12, or silicon removal module, is provided with an adsorption substance for adsorbing a silicon nitride etching product, i.e., a silicon compound, and an etching solution flowing out of the etching chamber 20 during or after etching flows through the adsorption module 12, wherein the silicon nitride etching product, i.e., the silicon compound, of the silicon nitride material is removed by the adsorption module 12.
Based on the fact that the wet etching apparatus is a silicon nitride wet etching apparatus, the etching chamber 20 is used for containing an etching solution containing phosphoric acid and a substrate to be etched containing silicon nitride, so as to etch silicon nitride materials. The etching chamber 20 comprises an etching liquid outlet and an etching liquid inlet, the adsorption module 12 is used for adsorbing silicon oxide compounds of silicon nitride etching products, namely, adsorbents including but not limited to solid adsorbents, and the etching liquid after the silicon nitride etching flows through the adsorption module 12, wherein the etching liquid refers to etching liquid containing phosphoric acid, and the silicon compounds of the silicon nitride etching products are removed by the adsorption module 12. In a further example, the other end of the adsorption module 12 is communicated with the liquid inlet of the etching chamber 20, so that the phosphoric acid liquid with the silicon compound removed by the adsorption module 12 is re-conveyed back to the etching chamber 20, and online processing can be realized, which helps to further simplify the equipment structure, improve the production efficiency and reduce the production cost.
In a further example, the wet etching apparatus may further include several of the circulation line 11, the pump 13, the filter 14, the heater 15, the fluid infusion module 17, and the automatic control module, for example, the above structures may be provided, or portions may be provided according to needs, which is not limited herein.
In this embodiment, one end of the circulation pipeline 11 is communicated with the liquid discharge port of the etching chamber 20, or the adsorption module 12 is communicated with the liquid discharge port of the etching chamber 20 through the circulation pipeline 11, and the other end of the circulation pipeline may be communicated with the liquid inlet of the etching chamber 20, the adsorption module 12, the pump 13, the filter 14 and the heater 15 are all disposed on the circulation pipeline 11 and communicated with the circulation pipeline 11, the pump 13 is used for providing power to promote the flow of the etching liquid, for example, to promote the flow of the etching liquid in the whole circulation pipeline 11, wherein more than one pump 13 may be disposed on the whole circulation pipeline 11, and a plurality of pumps 13 may be disposed at different positions, for example, the pump 13 may be disposed between the liquid discharge port and the adsorption module 12, and may also be disposed between the adsorption module 12 and the filter 14; the heater 15 is disposed between the filter 14 and the liquid inlet of the etching chamber 20, and is configured to heat the phosphoric acid etching liquid finally conveyed into the etching chamber 20, and the water content and the temperature of the phosphoric acid etching liquid are adjusted to the water content and the temperature required by the etching process by the liquid replenishing module 17, such as the water replenishing module, and the heater 15, so as to maintain the water content and the temperature of the phosphoric acid etching liquid finally entering the etching chamber 20 within a certain range, so as to enable the processed etching liquid to be directly used for etching silicon nitride, and certainly, the liquid replenishing module 17 may not be disposed as required, and directly replenish water into the etching chamber 20, which is not limited excessively here.
The adsorption module 12 is provided with an adsorbent (also called as an adsorption substance or called as a silicon removal substance) for adsorbing silicon nitride etching product silicon compounds, when etching liquid containing the silicon nitride etching product silicon compounds flows through the adsorption module 12, the silicon compounds can be adsorbed on the adsorbent to reduce the concentration of the silicon compounds in phosphoric acid etching liquid, and the adsorbent can comprise a solid, liquid or gel-like adsorbent, wherein the adsorbent can comprise any one or more of ion exchange resin, aluminum oxide, zirconium oxide, titanium oxide, silicon oxide and organic silicon compounds, or a substance obtained by modifying any one or more surface groups of the adsorbent, and the group modification refers to modification by using one or more of fluorine groups, sulfonic acid groups, carboxyl groups, cyclohexyl groups, trimethyl aminopropyl groups, benzene sulfonic acid propyl groups, ethylene diamine-N-propyl groups and surface groups of the adsorbent.
By way of example, the adsorbent may include silicon, silicon carbide, silicic acid polymers, hydroxyl group-containing polymers, carboxyl group-containing polymers, and fluorine-based modified materials of any one or more of the foregoing adsorbents.
Specifically, the adsorbent may be solid or liquid at normal temperature, for example, 25 ℃. When the adsorbent is a solid adsorbent, the solid adsorbent may be in a form, for example, surface modified, porous, crystalline, or other form. When the adsorbent is a solid adsorbent, it may include various shapes such as a sheet shape. When the adsorbent is a solid adsorbent, the adsorbent can be formed by partially or completely wrapping a non-adsorbent material with an adsorbent material. As an example, the adsorbent may be loaded in the adsorption module 12 in the following manner. Firstly, the adsorbent is placed in the adsorption module 12, and the adsorbent is prevented from moving out of the adsorption module 12 by arranging filtering devices with different shapes in the adsorption module 12; secondly, the adsorbent is processed into a different shape of unitary filter structure, which is placed in the adsorption module 12.
As an example, the adsorbent can be provided to the adsorption module by an adsorbent supply module, which is connected to the adsorption module and is not shown here.
As an example, the operation modes of the adsorption module 12 include a continuous type and a batch type for continuously and batch-wise removing the etching product silicon compound in the etching solution, respectively. Specifically, as shown in fig. 1 and fig. 2, this embodiment illustrates a diagram that the adsorption module 12 is suitable for batch-type work, wherein when the adsorption module 12 works, the valve 16, such as a three-way valve, is adjusted to enable the section a of the pipe segment to be in a closed state, when the adsorption module 12 needs to be replaced, such as cleaned, the valve 16 is used to enable the section a of the pipe segment to be in an open state and the section B of the pipe segment to be in a closed state, so as to suspend the adsorption process of the adsorption module 12 and avoid stagnation of the whole etching apparatus, and when the adsorption module 12 can work, the valve 16 can be adjusted again to enable the section B of the pipe segment to be in an open state, and specific settings can be selected according to needs. Of course, the adsorption module 12 may be selected for a continuous mode of operation, in which case the section a is removed with reference to fig. 3.
In order to prevent the adsorbent from flowing out of the adsorption module 12, it is preferable that a filtering unit (not shown) is further disposed in the adsorption module 20 to filter the adsorbent through the filtering unit to separate the adsorbent from the etching solution, wherein the method for separating the adsorbent from the etching solution may include methods such as filtering, cooling, and precipitation, and it is preferable that the particle size of the adsorbent is larger than the filtering precision of the filtering unit to prevent the adsorbent from entering the circulation line.
After the etching solution discharged from the liquid discharge port of the etching chamber 20 is removed from the adsorption module 12, the phosphoric acid etching solution after the primary treatment is conveyed to the filter 14 by the aid of the pump 13 for further filtering treatment, and then is subjected to liquid replenishment, such as water replenishment, by the liquid replenishment module 17 and the heater 15, so as to adjust the water content of the phosphoric acid etching solution, and is heated to reach a preset process temperature, and finally is conveyed to the etching chamber. The replenishment module 17 may also directly replenish the etching chamber 20 with water. Because the silicon compound is removed, the workload of the filter on the etching equipment can be reduced, and the service life of the filter can be prolonged.
In one example, the circulation line 11 may be in direct communication with the etch chamber 20.
By way of example, the etch chamber 20 may comprise a multi-piece etch chamber or a single piece etch chamber.
Specifically, as shown in fig. 1 to 3, the etching chamber 20 is a multi-piece etching chamber, such as a tank type etching chamber, for simultaneously etching a plurality of substrates, an outer tank for collecting the discharged etching solution is disposed between the etching chamber 20 and the adsorption module 12, and the etching chamber 20 may also include an inner tank for etching silicon nitride, for example, and an outer tank for collecting the phosphoric acid etching solution overflowing in a circulation manner, and the phosphoric acid etching solution in use overflows from the inner tank, is collected by the outer tank, is transported to the circulation pipeline 11, and is processed and then transported back to the inner tank. Of course, the etching chamber 20 may be a single-wafer type etching chamber as shown in FIG. 4 to meet the requirement of single-wafer processing.
In this embodiment, the etching chamber 20 is a circulating overflow tank, the outer tank is located outside the inner tank, the phosphoric acid etching solution overflowing from the inner tank after etching silicon nitride is discharged into the outer tank, and then is conveyed to the circulating pipeline 11, and the processed etching solution enters the inner tank to etch the silicon nitride substrate. Of course, in other examples, the outer tank may be disposed at the bottom of the inner tank, or the inner tank and the outer tank may be disposed at different positions, which is not limited to this.
As an example, the number of the adsorption modules 12 may be single or multiple, and when there are multiple adsorption modules 12, the multiple adsorption modules 12 may be all connected in series or all connected in parallel, and the adsorption modules 12 may also be partially connected in series or partially connected in parallel, which is not limited strictly. The wet etching apparatus may further include an adsorbent regeneration module (not shown), the regeneration module is connected to the adsorption module 12, for example, the regeneration module includes a flushing pipeline, when the adsorption module 12 needs to be cleaned, the control valves at two ends of the adsorption module 12 are closed, the flushing pipeline is started to clean the adsorption module 12, and the waste liquid after cleaning is directly discharged. The regeneration module can be either cleaned when needed or the adsorption module 12 can be activated and regenerated by introducing a special liquid when needed.
In one example, as shown in fig. 1, the wet etching apparatus further includes a temperature adjustment module (not shown) for adjusting the temperature of the phosphoric acid etching solution, and the adsorption effect of the adsorption module 12 can be adjusted by the temperature adjustment. The temperature adjusting module can be connected with the adsorption module 12 and/or arranged on the circulation pipeline 11 between the outer tank and the adsorption module 12 (i.e. the temperature adjusting module can be single or more than two). The temperature adjusting module may be a heat exchanger, and the heat exchanger may be disposed on the circulation pipeline 11 between the liquid discharge port of the etching chamber 20 and the adsorption module 12 to control the temperature of the phosphoric acid etching solution in the circulation pipeline 11. Of course, in other examples, the temperature adjusting module may also directly act on the adsorption module 12, for example, by using a heating unit or a cooling unit in the temperature control module to control the temperature of the adsorbent in the adsorption module 12.
In order to accurately control the component proportion of the treated phosphoric acid etching solution and improve the treatment effect, as an example, the wet etching apparatus further includes a monitoring module disposed on the circulation pipeline 11 or the adsorption module 12 to sample and analyze the phosphoric acid etching solution in the circulation pipeline 11. The monitoring module may include, but is not limited to, an inductively coupled plasma emission spectrometer and infrared spectroscopy for detecting the concentration of silicon compounds in the phosphoric acid etching solution. The monitoring module may be single or multiple, such as at least two, one is disposed on the circulation line 11 between the adsorption module 12 and the outer tank, and one is disposed on the circulation line 11 between the adsorption module 12 and the filter 14, so as to analyze the etching solution before and after adsorption by the adsorption module 12, for example, phosphoric acid etching solution. Of course, in other examples, a sampling pipeline may also be separately provided, the two ends of the sampling pipeline are connected to the circulation pipeline 11, the pipe diameter of the sampling pipeline is far smaller than the pipe diameter of the circulation pipeline 11 (for example, less than one fourth of the pipe diameter of the circulation pipeline 11), the monitoring module is disposed on the sampling pipeline, and the front end and the rear end of the monitoring module may also be provided with valves for sampling. The advantage that sets up the sample pipeline lies in, firstly avoids influencing because of the sample the liquid flow in the circulating line 11, secondly the sample pipeline of miniflow is more convenient for sample analysis. The extracted etching solution sample passes through a sample processing unit in the analysis module, for example, is mixed with a certain amount of ultrapure water for quantitative dilution, and enters an analysis instrument for detection.
As an example, the wet etching apparatus may further include a flow control module (not shown) that may be disposed on the circulation line 11 between the adsorption module 12 and the outer tank to monitor the liquid flow in the circulation line 11 in real time. The flow control module may be plural, and another flow control module may be provided on the circulation line 11 between the heater 15 and the inner tank. The circulation pipeline 11 may further include a temperature detection module (not shown), which may be disposed on the circulation pipeline 11 between the adsorption module 12 and an outer tank (i.e., a liquid outlet of the etching chamber) to detect the temperature of the phosphoric acid etching solution in real time; or the temperature detection module and the flow control module may be integrated into the same module and disposed on the circulation line 11 between the outer tank and the adsorption module 12.
The filter 14 may be a high efficiency filter, and the number thereof may be single or plural. When there are a plurality of filters 14, the plurality of filters 14 may be connected in series, or connected in parallel, or partially connected in series. Preferably, a plurality of the filters 14 are arranged in parallel to form at least two pipelines, so that when the filter 14 on one of the flow paths fails, the other flow path can be started in time, and the stability of the wet etching equipment is improved.
As an example, the wet etching apparatus further comprises an automatic control module, such as a controller, to implement automatic control of the wet etching apparatus. The controller may be electrically connected to the aforementioned modules with detection functions, such as a monitoring module, a heater, etc., to control the operations of the respective modules according to the respective detection results.
In another example, as shown in fig. 2, the wet etching apparatus is a silicon oxide etching apparatus, the etching chamber 20 is configured to contain a silicon oxide etching solution and a substrate to be etched containing silicon oxide for silicon oxide etching, the silicon oxide etching apparatus further includes one or more of a circulation pipeline 11, a pump 13, a filter 14 and a monitoring module, preferably all of the foregoing structures, one end of the circulation pipeline 11 is communicated with a liquid outlet of the etching chamber 20, the other end of the circulation pipeline is communicated with a liquid inlet of the etching chamber 20, and the adsorption module 12, the pump 13, the filter 14 and the monitoring module are communicated with the circulation pipeline. More specifically, the pump 13, the adsorption module 12 and the filter 14 are sequentially arranged on the circulation pipeline between the liquid outlet and the liquid inlet of the etching chamber 20 in a direction away from the liquid outlet, and the number of the monitoring modules is two, one is arranged on the circulation pipeline 11 between the pump 13 and the adsorption module 12, and the other is arranged on the circulation pipeline 11 between the adsorption module 12 and the filter 14, so that the concentration of the silicon compound before and after the etching solution discharged from the etching chamber 20 flows through the adsorption module 12 can be detected. The functional roles of the modules are referred to the above description, and are not repeated for brevity. The silicon oxide etching equipment can also be provided with an automatic control module such as a controller, and the controller is connected with the monitoring module and other modules with detection functions so as to control the operation of other modules according to the detection result of each module and improve the automation level of the equipment.
In another example, as shown in fig. 3, the wet etching apparatus is a silicon etching apparatus, the etching chamber 20 is used for containing a silicon etching solution and a silicon substrate to be etched to perform silicon oxide etching, the silicon etching apparatus further includes one or more of a circulation pipeline 11, a pump 13, a filter 14, a heating module 15 and a monitoring module, preferably all of the above structures, one end of the circulation pipeline is communicated with a liquid outlet of the etching chamber 20, the other end of the circulation pipeline is communicated with a liquid inlet of the etching chamber 20, and the adsorption module 12, the pump 13, the filter 14, the heater module 15 and the monitoring module are communicated with the circulation pipeline. More specifically, the pump 13, the adsorption module 12, the filter 14 and the heater module 15 are sequentially arranged on the circulation pipeline between the liquid outlet and the liquid inlet of the etching chamber 20 in a direction away from the liquid outlet, and the number of the monitoring modules is two, one is arranged on the circulation pipeline between the pump 13 and the silicon removal module 12, and the other is arranged on the circulation pipeline between the silicon removal module 12 and the filter 14, so that the concentration of the silicon compound before and after the etching solution discharged from the etching chamber passes through the adsorption module 12 can be detected. The functional roles of the modules are referred to the above description, and are not repeated for brevity. The silicon etching equipment can also be provided with a controller, and the controller is connected with the modules with detection functions, such as the monitoring module, so that the operation of other modules can be controlled according to the detection result of each module, and the automation level of the equipment is improved.
As shown in fig. 1 to fig. 3, the wet etching apparatus may be a multi-piece processing apparatus, such as a slot type, that is, etching processing may be performed on tens of substrates at the same time, and the etching apparatus has the advantages of high etching efficiency, etc., and a conventional multi-piece wet etching apparatus needs to frequently replace a new etching solution. Of course, the wet etching apparatus may also be a single wafer processing apparatus, as shown in fig. 4, in this case, a stage for placing the substrate is usually further disposed in the etching chamber, and the processed etching solution is sprayed into the etching chamber through a nozzle. The wet etching equipment is simultaneously suitable for the two etching modes, can effectively remove the etching product silicon compound in the etching solution, is beneficial to improving the etching efficiency and the yield, and is beneficial to reducing the etching cost and improving the equipment output rate through the cyclic recycling of the etching solution.
The present invention further provides a wet etching method, which can be performed by the wet etching apparatus in any of the above schemes, but is not limited thereto, and for the introduction of the wet etching apparatus, reference is made to the foregoing, and details are not repeated for the sake of brevity.
The wet etching method may include the steps of:
step S1: exposing one or a combination of silicon, silicon oxide or silicon nitride materials on the substrate to an etching solution for etching process to generate an etching product silicon compound;
step S2: and adsorbing a silicon compound by using an adsorbent, and separating the adsorbent from the etching solution to realize the cyclic utilization of the etching solution.
Specifically, the flow of the wet etching method can refer to fig. 5, wherein the wet etching method can be any one or a combination of a silicon wet etching method, a silicon nitride wet etching method and a silicon oxide wet etching method.
In particular, after the silicon compound in the etching solution is adsorbed by the adsorbent, the adsorbent is generally separated from the etching solution, and if the adsorption is not separated, the adsorbent contacts the substrate being processed, which affects the quality of the substrate surface, such as a solid adsorbent. In special cases, the adsorbent and the etching solution may not need to be separated, for example, the adsorbent is a liquid adsorbent, and when the adsorbent and the etching solution form a homogeneous system, the adsorbent and the etching solution may not need to be separated.
When the wet etching is performed, the etching solution may include one or more of a phosphoric acid-containing solution, a hydrofluoric acid-containing solution, a tetramethylammonium hydroxide-containing solution, a potassium hydroxide-containing solution, and a sodium hydroxide-containing solution. The adsorbent can comprise one or more of ion exchange resin, alumina, zirconia, titania, silica and organic silicon compounds, or a substance obtained by modifying the surface groups of one or more of the adsorbents, wherein the group modification refers to modification by one or more of sulfonic acid group, carboxyl group, cyclohexyl group, trimethyl aminopropyl group, benzenesulfonic acid propyl group, ethylenediamine-N-propyl group and the surface groups of the adsorbents. For example, the adsorbent may comprise silicon, silicon carbide, silicic acid polymers, hydroxyl group-containing polymers, carboxyl group-containing polymers, and fluorine-based modified materials of any one or more of the foregoing adsorbents. The method for separating the adsorbent from the etching solution can comprise one or more of filtration, temperature reduction and precipitation.
Different materials to be etched have different etching products and different silicon compounds in different etching solutions. For example, the silicon nitride material is etched in a phosphoric acid solution to generate a silicon oxide compound, the silicon oxide material is etched in a hydrofluoric acid solution to generate a silicon fluoride compound, the silicon material is etched in an acidic etching solution, such as a mixed solution of hydrofluoric acid and nitric acid, to generate a fluorosilicic acid compound, and the silicon material is etched in an alkaline etching solution, such as a sodium hydroxide solution, to generate a silicon oxide compound. According to different etching product silicon compounds, different groups on the surface of the adsorbent, such as hydroxyl, carboxyl, fluorine, cyclohexyl and the like, are utilized to form hydrogen bonds, van der Waals forces or chemical bond acting forces with etching product silicon compound groups in the etching solution, and the silicon compounds are adsorbed out of the etching solution and are retained on the surface of the adsorbent material, so that the etching product silicon compounds in the etching solution are removed. For example, silicon-oxygen compounds generated from silicon nitride in a phosphoric acid solution and silicon-oxygen compounds generated from silicon in an alkaline etching solution form silicon-oxygen-silicon or carbon-oxygen-silicon bonds with groups on the surface of the adsorbent, such as silicon hydroxyl groups and carboxyl groups, so as to be adsorbed on the surface of the adsorbent.
Wherein the concentration of the silicon compound in the etching solution is adjusted by adjusting the adsorption of the silicon compound on the surface of the adsorbent, and the adjusting method may include one or a combination of adjusting the temperature of the etching solution, adjusting the concentration of the etching solution, and adjusting the temperature of the adsorbent.
Furthermore, when the adsorbent is used for adsorbing the silicon compound, an adsorption accelerator, such as one or a combination of water, hydrofluoric acid, ammonium fluoride and ammonium bifluoride, can be provided to accelerate the speed of the silicon compound adsorbed on the surface of the adsorbent, so as to accelerate the removal of the silicon compound and improve the efficiency.
The wet etching method is carried out by adopting the wet etching equipment, and after the silicon-containing film is etched in the etching chamber, for example, the used etching solution or the etching solution in the silicon nitride material etching process, for example, the etching solution containing phosphoric acid flows through the adsorption module, and the silicon compound contained in the silicon nitride wet etching product is removed by the adsorption module. Under the condition that the water replenishing module and the heater module are arranged, the phosphoric acid etching solution can be treated by adjusting the concentration and the temperature, and the phosphoric acid etching solution can be directly used for etching the silicon nitride film, so that the etching efficiency can be improved, the use amount of the phosphoric acid etching solution can be effectively reduced, the replacement frequency of the etching solution is reduced, and the etching cost can be effectively reduced.
In summary, the present invention provides a wet etching apparatus and a wet etching method. The invention provides wet etching equipment which comprises an etching chamber and an adsorption module, wherein the adsorption module capable of absorbing silicon compounds is arranged on a recovery path of etching liquid, so that the service life of the etching liquid can be effectively prolonged, the use cost is reduced, the environmental pollution caused by the discharge of waste liquid of the etching liquid is reduced, the frequency of replacing the etching liquid can be reduced, and the production efficiency is improved. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (14)
1. The wet etching equipment is characterized by comprising an etching chamber and an adsorption module, wherein one end of the adsorption module is communicated with a liquid outlet of the etching chamber and/or the adsorption module is arranged in the etching chamber; the etching chamber accommodates a substrate to be processed and an etching solution, and the etching solution is in contact with the substrate to etch a material on the substrate and generate an etching product silicon compound, wherein the material on the substrate comprises any one or combination of silicon, silicon oxide and silicon nitride; the adsorption module is provided with an adsorbent, etching liquid in the etching chamber enters the adsorption module, and etching product silicon compounds are removed by the adsorbent in the adsorption module.
2. The wet etching apparatus of claim 1, wherein the adsorbent comprises one or more of ion exchange resin, alumina, zirconia, titania, silica, and an organosilicon compound, or a surface group-modified material of one or more of the foregoing adsorbents, wherein the group modification is modification using one or more of fluorine group, sulfonic acid group, carboxyl group, cyclohexyl group, trimethylaminopropyl group, benzenesulfonic acid propyl group, ethylenediamine-N-propyl group, and a surface group of the foregoing adsorbents.
3. The wet etching apparatus of claim 1, wherein the adsorbent comprises silicon, a silicic acid polymer, silicon carbide, a hydroxyl group-containing polymer, a carboxyl group-containing polymer, and a fluorine-based modified material of any one or more of the foregoing adsorbents.
4. The wet etching apparatus of claim 1, wherein the adsorption module further comprises a filtering unit, by which the adsorbent is prevented from flowing out of the adsorption module.
5. The wet etching apparatus of claim 1, further comprising a monitoring module that detects a concentration of the silicon compound.
6. The wet etching apparatus of claim 1, further comprising a regeneration module for the sorbent.
7. The wet etching apparatus of any one of claims 1 to 6, further comprising one or more of a circulation line, a pump, a filter, a heater, a heat exchanger, a fluid replacement module, and an automatic control module.
8. A wet etching method, comprising the steps of:
step S1, exposing one or a combination of silicon, silicon oxide or silicon nitride materials on a substrate to an etching solution for etching process to generate an etching product silicon compound;
step S2: and adsorbing a silicon compound by using an adsorbent, and separating the adsorbent from the etching solution to realize the cyclic utilization of the etching solution.
9. The wet etching method of claim 8, wherein the etching solution comprises one or more of a phosphoric acid-containing solution, a hydrofluoric acid-containing solution, a tetramethylammonium hydroxide-containing solution, a potassium hydroxide-containing solution, and a sodium hydroxide-containing solution.
10. The wet etching method according to claim 8, wherein the adsorbent comprises one or more of ion exchange resin, alumina, zirconia, titania, silica, and an organic silicon compound, or a modified surface group of one or more of the adsorbents, and the group modification is modification with one or more of a sulfonic acid group, a carboxyl group, a cyclohexyl group, a trimethylaminopropyl group, a benzenesulfonylpropyl group, an ethylenediamine-N-propyl group, and a surface group of the adsorbent.
11. The wet etching method of claim 8, wherein the adsorbent comprises silicon, silicon carbide, a silicic acid polymer, a hydroxyl group-containing polymer, a carboxyl group-containing polymer, and a fluorine-based modified material of any one or more of the foregoing adsorbents.
12. The wet etching method of claim 8, wherein the method for separating the adsorbent from the etching solution comprises one or more of filtering, cooling and precipitating.
13. The wet etching method according to claim 8, wherein the concentration of the silicon compound in the etching solution is adjusted by adjusting adsorption of the silicon compound on the surface of the adsorbent, wherein the adjustment method comprises one or a combination of adjusting the temperature of the etching solution, adjusting the concentration of the etching solution, and adjusting the temperature of the adsorbent.
14. The wet etching method according to claim 8, further comprising adding an adsorption accelerator in step S2, wherein the adsorption accelerator comprises one or a combination of water, hydrofluoric acid, ammonium fluoride and ammonium bifluoride.
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| PCT/CN2022/125313 WO2023071826A1 (en) | 2021-10-27 | 2022-10-14 | Wet etching device and wet etching method |
| TW111140972A TW202329240A (en) | 2021-10-27 | 2022-10-27 | Wet etching equipment and wet etching method |
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| CN2021112549950 | 2021-10-27 | ||
| CN202111254995 | 2021-10-27 |
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| CN (1) | CN115148643A (en) |
| TW (1) | TW202329240A (en) |
| WO (1) | WO2023071826A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023071826A1 (en) * | 2021-10-27 | 2023-05-04 | 中国科学院上海微系统与信息技术研究所 | Wet etching device and wet etching method |
| CN116837466A (en) * | 2023-08-31 | 2023-10-03 | 合肥晶合集成电路股份有限公司 | Phosphoric acid etching solution recovery method and etching method |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6207068B1 (en) * | 1998-11-18 | 2001-03-27 | Advanced Micro Devices, Inc. | Silicon nitride etch bath system |
| TWI233157B (en) * | 2002-09-17 | 2005-05-21 | M Fsi Ltd | Regeneration process of etching solution, etching process, and etching system |
| CN100399518C (en) * | 2004-06-22 | 2008-07-02 | 茂德科技股份有限公司 | Etching system and treatment of etching agent |
| SG11202109069WA (en) * | 2019-02-20 | 2021-09-29 | Weimin Li | Need for si3n4 selective removal by wet chemistry |
| CN115148643A (en) * | 2021-10-27 | 2022-10-04 | 中国科学院上海微系统与信息技术研究所 | Wet etching equipment and wet etching method |
-
2022
- 2022-08-05 CN CN202210938351.1A patent/CN115148643A/en active Pending
- 2022-10-14 WO PCT/CN2022/125313 patent/WO2023071826A1/en unknown
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2023071826A1 (en) * | 2021-10-27 | 2023-05-04 | 中国科学院上海微系统与信息技术研究所 | Wet etching device and wet etching method |
| CN116837466A (en) * | 2023-08-31 | 2023-10-03 | 合肥晶合集成电路股份有限公司 | Phosphoric acid etching solution recovery method and etching method |
| CN116837466B (en) * | 2023-08-31 | 2023-12-08 | 合肥晶合集成电路股份有限公司 | Phosphoric acid etching solution recovery method and etching method |
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| TW202329240A (en) | 2023-07-16 |
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