CN114242585A - Method and device for removing polycrystalline silicon sacrificial gate in gate-last process - Google Patents

Method and device for removing polycrystalline silicon sacrificial gate in gate-last process Download PDF

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Publication number
CN114242585A
CN114242585A CN202010943482.XA CN202010943482A CN114242585A CN 114242585 A CN114242585 A CN 114242585A CN 202010943482 A CN202010943482 A CN 202010943482A CN 114242585 A CN114242585 A CN 114242585A
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supply line
polysilicon
gate
chemical
etchant
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李春雨
胡艳鹏
卢一泓
李琳
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Institute of Microelectronics of CAS
Zhenxin Beijing Semiconductor Co Ltd
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Institute of Microelectronics of CAS
Zhenxin Beijing Semiconductor Co Ltd
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Priority to CN202010943482.XA priority Critical patent/CN114242585A/en
Publication of CN114242585A publication Critical patent/CN114242585A/en
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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
    • H01L21/02—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
    • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
    • H01L21/321—After treatment
    • H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
    • H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
    • H01L21/32134—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by liquid etching only
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409—Unipolar field-effect transistors
    • H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H01L29/66545—Unipolar field-effect transistors with an insulated gate, i.e. MISFET using a dummy, i.e. replacement gate in a process wherein at least a part of the final gate is self aligned to the dummy gate

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Ceramic Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Weting (AREA)

Abstract

The invention discloses a method and a device for removing a polycrystalline silicon sacrificial gate in a gate-last process, belongs to the technical field of semiconductors, and solves the problem that polycrystalline silicon residue is generated in the bottom area of a gate trench in the prior art. The method for removing the polysilicon sacrificial gate adopts a polysilicon etching agent to carry out wet etching on polysilicon to form a groove without polysilicon residue, wherein the polysilicon etching agent contains isopropanol. The polysilicon etching agent containing isopropanol can obviously reduce the surface tension, so that the polysilicon etching agent is fully contacted with the residual polysilicon at the bottom of the gate trench, and the reaction is enhanced, thereby solving the residual problem of the polysilicon.

Description

Method and device for removing polycrystalline silicon sacrificial gate in gate-last process
Technical Field
The invention belongs to the technical field of semiconductors, and particularly relates to a method and a device for removing a polycrystalline silicon sacrificial gate in a gate-last process.
Background
The main devices in integrated circuits, especially very large scale integrated circuits, are Metal Oxide Semiconductor (MOS) field effect transistors, referred to as MOS transistors for short. Since the invention of MOS transistors, their geometries have been shrinking. In this situation, various practical and fundamental limitations and technical challenges begin to emerge, and further scaling down of device dimensions is becoming increasingly difficult. In the process of shrinking the transistor device, the gate leakage current is higher due to the reduction of the thickness of the gate oxide layer. To this end, solutions have been proposed to replace the conventional heavily doped polysilicon gate and silicon dioxide (or silicon oxynitride) gate dielectric with a metal gate and a high dielectric constant (K) gate dielectric layer.
In the process of replacing a polysilicon gate with a metal gate in a gate-last semiconductor process to improve the performance of a device, a dummy polysilicon gate needs to be removed first, and then the metal gate is used for replacement.
In the existing pseudo polysilicon gate removing process adopting alkali liquor to carry out wet etching, polysilicon residue is generated in the bottom area of a gate groove, and as shown in figure 1, the conductivity of a semiconductor device is influenced. Even if the time of the pseudo polysilicon gate removal process is increased, the problem cannot be effectively reduced, and even the problem of over-etching of the gate oxide layer can be caused.
Disclosure of Invention
In view of the above analysis, the present invention aims to provide a method and an apparatus for removing a polysilicon sacrificial gate in a gate-last process, which solves the problem in the prior art that polysilicon residue is generated in the bottom region of a gate trench.
The purpose of the invention is mainly realized by the following technical scheme:
the invention provides a method for removing a polysilicon sacrificial gate in a gate-last process, which adopts a polysilicon etching agent to carry out wet etching on polysilicon to form a groove without polysilicon residue, wherein the polysilicon etching agent contains isopropanol.
In one possible design, the polysilicon etching agent further contains an alkali solution, wherein the alkali solution is ammonia water or tetramethyl ammonium hydroxide, and the alkali solution is diluted by deionized water.
In one possible design, the alkali liquor, the isopropanol and the deionized water are respectively added into a chemical mixing tank and uniformly mixed, and then enter an etchant supply line.
In one possible design, the alkali solution and the deionized water are added into a chemical mixing tank and are uniformly mixed, then the mixture enters an etchant supply line, and isopropanol is added into the etchant supply line.
In one possible design, the chemicals in the chemical mixing tank are circulated to the chemical mixing tank after entering the heater and the filter in sequence through the circulating pump.
In one possible design, the volume ratio of lye to deionized water is 1: 2-1: 10; the volume of the isopropanol is 0.5-5% of the volume of the mixed solution of the alkali liquor and the water.
In one possible design, the etching temperature of the etchant is 30-80 ℃.
In one possible design, the flow rate of the etchant is 600-2500 ml/min.
The invention also provides a device for removing the polycrystalline silicon sacrificial gate in the gate-last process, which comprises a chemical mixing tank, a chemical supply line, a chemical heating and filtering circulating pipeline and an etchant supply line;
the upper part of the chemical mixing tank is provided with a whole or partial chemical supply line;
a medicine heating and filtering circulation pipeline is arranged on one side of the chemical mixing tank; the chemical agent is used for heating and filtering the chemical agent required by the polysilicon etching agent; along the circulation direction, a circulation pump, a heater and a filter are sequentially arranged on the medicine heating and filtering circulation pipeline;
an etchant supply line is arranged at the bottom of the chemical mixing tank and used for supplying etchant; when part of the chemical supply lines are arranged at the upper part of the chemical mixing tank, the rest of the chemical supply lines are arranged on the etching agent supply lines.
In one possible design, the medicine supply line comprises a deionized water supply line, an alkali liquor supply line and an isopropanol supply line; the deionized water supply line, the alkali liquor supply line and the isopropanol supply line are respectively arranged at the upper part of the chemical mixing tank.
In one possible design, the medicine supply line comprises a deionized water supply line, an alkali liquor supply line and an isopropanol supply line; the deionized water supply line and the alkali liquor supply line are respectively arranged at the upper part of the chemical mixing tank, and the isopropanol supply line is arranged on the etchant supply line.
Compared with the prior art, the invention can at least realize one of the following technical effects:
1) the polysilicon etching agent adopted by the wet etching comprises isopropyl alcohol (IPA), and the IPA can obviously reduce the surface tension of the polysilicon etching agent, so that the IPA can be fully contacted with the residual polysilicon at the bottom of the gate trench, and the reaction is enhanced, thereby solving the residual problem of the polysilicon. And the thickness of the gate oxide layer is not reduced because the etching time needs to be prolonged.
2) The upper part of the chemical mixing tank is provided with a whole or partial chemical supply line; the isopropanol supply line is arranged on the etchant supply line, and when the etching process does not need IPA, the IPA supply is stopped without integrally replacing the solution in the chemical mixing tank; or the isopropanol supply line sets up on chemical blending tank upper portion, adopts chemical blending tank can make the medicine mix more evenly, and it is more accurate to add IPA dosage control, and polysilicon remove device's simple structure cost is lower.
3) A medicine heating and filtering circulation pipeline is arranged on one side of the chemical mixing tank; along the circulation direction, a circulation pump, a heater and a filter are sequentially arranged on the medicine heating and filtering circulation pipeline. The heater heats the etchant to achieve an ideal reaction rate, so that an ideal etching effect is achieved; the filter can filter particles in the etchant and prevent impurities from blocking the etchant supply line during etching.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.
FIG. 1 is a schematic diagram illustrating the effect of removing polysilicon in the prior art;
FIG. 2 is a schematic diagram illustrating the effect of removing polysilicon according to the present invention;
FIG. 3 is a first schematic view of an apparatus for removing polysilicon according to the present invention;
FIG. 4 is a second schematic view of a polysilicon removal apparatus according to the present invention;
FIG. 5 is a schematic view of an apparatus for removing polysilicon in comparative example 1.
Reference numerals
1-a semiconductor substrate; 2-an interfacial layer; 3-a sacrificial gate; 4-a dielectric layer; 5-side wall; 6-chemical mixing tank; 7-deionized water supply line; 8-supplying alkali liquor; a 9-isopropanol feed line; 10-etchant supply line; 11-a circulation pump; 12-a heater; 13-filter.
Detailed Description
Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is illustrative only and is not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure.
Various structural schematics according to embodiments of the present disclosure are shown in the figures. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers, and relative sizes and positional relationships therebetween shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, as actually required.
In the context of the present disclosure, when a layer/element is referred to as being "on" another layer/element, it can be directly on the other layer/element or intervening layers/elements may be present. In addition, if a layer/element is "on" another layer/element in one orientation, then that layer/element may be "under" the other layer/element when the orientation is reversed.
The embodiment of the application is applied to the removal of the polysilicon sacrificial gate in the gate-last process. How to remove the sacrificial gate by using the technical scheme of the invention will be described according to one embodiment of the invention.
As shown in fig. 1 and fig. 2, the formation of the sacrificial gate and the source and drain in the replacement gate process has been completed on the semiconductor substrate 1. An interface layer 2, and in some embodiments a gate dielectric layer (not shown), is formed on the semiconductor substrate 1. A sacrificial gate 3, a side wall 5 surrounding the sacrificial gate 3 and a dielectric layer 4 on the semiconductor substrate 1 are arranged on the interface layer 2. In addition, source/drain regions, not shown, are formed on the semiconductor substrate 1.
Each part of the transistor in fig. 2 may be formed according to a conventional technique, for example, a gate dielectric layer and a sacrificial gate layer may be formed on the semiconductor substrate 1, then the sacrificial gate layer is etched to form a sacrificial gate, a sidewall is formed on the outer side of the sacrificial gate, and then a source-drain region is formed. And finally, depositing an interlayer dielectric layer on the whole semiconductor substrate, and performing CMP until the top of the sacrificial gate is exposed. The embodiments of the present invention are not limited thereto.
The sacrificial gate 3 is a polysilicon sacrificial gate, and in order to remove residual polysilicon in the bottom region of the gate trench, the wettability (wettability) of a polysilicon etching agent in wet etching needs to be improved. Wettability refers to the ability or propensity of a liquid to spread on a solid surface. The contact angle theta is at its minimum 0 deg. and at its maximum 180 deg.. The smaller the contact angle, the better the wettability. And theta is 0, the liquid completely wets the solid surface, the liquid spreads on the solid surface, the smaller the liquid surface tension is, the better the wetting performance is, the larger the liquid-solid contact area is, the more sufficient the reaction is. Microstructuring one surface will amplify the surface tension. A hydrophobic surface (having a contact angle greater than 90 °) will become more hydrophobic after microstructuring, and its new contact angle will increase compared to the original. However, a hydrophilic surface (having a contact angle less than 90 °) becomes more hydrophilic after microstructuring, and its new contact angle will be reduced from the original. The polysilicon has hydrophobicity, and the residual polysilicon at the bottom of the gate trench is more hydrophobic after the microstructure is amplified, so that the residual polysilicon is more difficult to contact and react with a polysilicon etching agent.
The polysilicon etching agent adopted by the wet etching method of the invention contains Isopropanol (IPA), which can obviously reduce the surface tension of the polysilicon etching agent, so that the IPA can be fully contacted with the residual polysilicon at the bottom of the gate trench, and the reaction is enhanced, thereby solving the residual problem of the polysilicon, as shown in figure 2.
The polysilicon etching agent also comprises an alkali liquor, wherein the alkali liquor is ammonia water (ammonia) or tetramethyl ammonium hydroxide (TMAH), and the alkali liquor is diluted by deionized water.
Specifically, the volume ratio of the alkali liquor to the deionized water is 1: 2-1: 10, as shown in 1: 4,1: 6,1: 8, etc.; the isopropanol is 0.5-5% (volume fraction) of the mixed solution of alkali liquor and water, such as 1%, 3%, etc. If the proportion of the alkali liquor is too low, the etching can not be carried out, and if the proportion of the alkali liquor is too high, the problem of poor etching consistency can be caused. If the content of isopropyl alcohol is too low, the effect of adding isopropyl alcohol cannot be achieved, and if the content is too high, the etching capability is reduced, and the cost is too high.
The temperature of the polysilicon etching agent is 30-80 ℃, the process time is prolonged when the temperature is too low, the productivity is reduced, and the consistency is deteriorated when the temperature is too high. The flow rate of the polycrystalline silicon etchant is 600-2500 ml/min during etching, if the flow rate is too low, the problem of poor consistency is caused when the whole wafer is processed, and the process time is prolonged; if the flow rate is too high, the cost is increased, and the control effect between the components such as the valve is likely to be different, thereby causing poor uniformity.
The adding method of the isopropanol comprises the following steps: directly adding alkali liquor, isopropanol and deionized water into a chemical mixing tank 6 and mixing uniformly. Adopt chemical blending tank 6 can make the medicine mix more evenly, it is more accurate to add IPA dosage control, and polysilicon remove device's simple structure cost is lower. However, when the liquid is changed, the liquid needs to be changed integrally, that is, when the process does not need IPA, the liquid in the chemical mixing tank 6 needs to be changed integrally.
Another method for adding isopropanol is: firstly, adding alkali liquor and deionized water into a chemical mixing tank 6, uniformly mixing, then connecting an isopropanol supply line to an etchant supply line 10, and mixing in real time during etching. IPA injection etchant supply line 10 is mixed in real time, an independent flow meter or a quantitative valve is needed to control the supply amount of IPA, and the IPA injection etchant supply line and the etchant are cooperatively controlled, so that the system is complex; however, when the etching process does not require IPA, the supply of IPA may be stopped without replacing the entire solution in the chemical mixing tank 6.
After the etching of the sacrificial gate is completed, a metal gate may be formed in the gate trench by conventional techniques, thereby completing the replacement gate process. Illustratively, the dummy gate may be directly filled with metal and excess metal removed by CMP to form a metal gate. According to some embodiments of the present invention, a gate dielectric layer, a work function metal layer and a gate conductor layer may be formed in the gate trench.
The invention also discloses a device for removing the polysilicon, which can be used for removing the polysilicon in a gate replacement process, and comprises a chemical mixing tank 6, a chemical supply line and an etchant supply line 10, as shown in fig. 3 and 4; the chemical mixing tanks 6 are used for processing the chemicals used by the polysilicon etchant, each chemical supply line is used for inputting one chemical to the chemical mixing tank 6 or the etchant supply line 10, and the etchant supply line 10 is used for outputting the etchant.
The medicine supply line comprises a deionized water supply line 7, an alkali liquor supply line 8 and an isopropanol supply line 9. The deionized water supply line 7 and the alkali liquor supply line 8 are both arranged on the chemical mixing tank 6. There are two methods of setting up the isopropanol feed line 9: one is arranged on the chemical mixing tank 6; the other is provided on the etchant supply line 10.
A chemical heating and filtering circulation pipeline is arranged on the chemical mixing tank 6, and a circulation pump 11, a heater 12 and a filter 13 are arranged on the chemical heating and filtering circulation pipeline in sequence; the circulation pump 11 is used to draw the liquid in the chemical mixing tank 6 from the bottom and re-flow it from above, on the one hand to promote the mixing of the chemicals used in the etchant, and on the other hand to draw the etchant from the chemical mixing tank 6 into the circulation pipe to filter and heat the etchant. The filtering of the etchant is to prevent impurities which cannot be dissolved in the chemicals from existing, the etchant supply line 10 is blocked during etching, and if the etchant is recycled, the filtering is needed even for multiple times, and particles in the solution are filtered and removed. The heating is to heat the etchant to a set temperature, so that the etching achieves a desired reaction rate and etching effect. The chemical reaction is temperature dependent, and generally the higher the temperature the faster the reaction, the faster the reaction rate can be obtained by heating the etchant, but in semiconductor processes the rate is not as fast as possible and needs to be controlled at a suitable temperature. The temperature of the polysilicon etching agent is controlled to be 30-80 ℃, the process time is prolonged when the temperature is too low, the productivity is reduced, and the consistency is poor when the temperature is too high. The heater can control heating temperature, and the precision is 0.5, and the filter can filter the granule more than 0.2 um.
When the isopropyl alcohol supply line 9 is provided on the etchant supply line 10, in order to prevent the temperature of the etchant from being lowered by the addition of isopropyl alcohol, thereby affecting the reaction rate, a second heater is provided on the isopropyl alcohol supply line 9. At this time, a quantitative valve or a flow meter is further provided on the isopropyl alcohol supply line 9 for adjusting the amount of IPA fed into the etchant supply line 10. The amount of IPA injected is controlled by a metering valve or flow meter.
Example 1
The polysilicon etching agent comprises isopropanol, ammonia water and deionized water, wherein the isopropanol is added from the upper part of a chemical mixing tank 6, and the volume ratio of the alkali liquor to the deionized water is 1: 2; the isopropanol accounts for 5 percent (volume fraction) of the mixed solution of the alkali liquor and the water; the temperature of the polysilicon etching agent is 30 ℃, and the flow rate of the etching agent during etching is 1000 ml/min.
In the pseudo-polysilicon gate removing process of wet etching, the bottom region of the gate trench is etched without polysilicon residue, and the problem of over-etching of the gate oxide layer is avoided.
Example 2
The polysilicon etching agent comprises isopropanol, ammonia water and deionized water, wherein the isopropanol is added from an etching agent supply line 10, and the volume ratio of the alkali liquor to the deionized water is 1: 10; the isopropanol accounts for 0.5 percent (volume fraction) of the mixed solution of the alkali liquor and the water; the temperature of the polysilicon etching agent is 80 ℃, and the flow rate of the etching agent during etching is 2000 ml/min.
In the pseudo-polysilicon gate removing process of wet etching, the bottom region of the gate trench is etched without polysilicon residue, and the problem of over-etching of the gate oxide layer is avoided.
Example 3
The polysilicon etching agent comprises isopropanol, TMAH and deionized water, wherein the isopropanol is added from the upper part of the chemical mixing tank 6, and the volume ratio of the alkali liquor to the deionized water is 1: 5; the isopropanol accounts for 3 percent (volume fraction) of the mixed solution of the alkali liquor and the water; the temperature of the polysilicon etching agent is 50 ℃, and the flow rate of the etching agent during etching is 1500 ml/min.
In the pseudo-polysilicon gate removing process of wet etching, the bottom region of the gate trench is etched without polysilicon residue, and the problem of over-etching of the gate oxide layer is avoided.
Example 4
The volume ratio of the alkali liquor to the deionized water is 1: 8; the isopropanol is 2 percent (volume fraction) of the mixed solution of the alkali liquor and the water. Adding the isopropanol, the ammonia water and the deionized water into a chemical mixing tank in proportion from an isopropanol supply line, an alkali liquor supply line and a deionized water supply line respectively for mixing. The liquid in the chemical mixing tank is pumped out from the bottom by the circulating pump, and then enters the chemical mixing tank again after being heated and filtered. The polysilicon etchant in the chemical mixing tank is mixed uniformly and heated to 60 ℃.
During etching, polysilicon etchant is fed from the etchant supply line over the polysilicon to be etched. The flow rate of the etchant during etching is 1800 ml/min.
In the pseudo-polysilicon gate removing process of wet etching, the bottom region of the gate trench is etched without polysilicon residue, and the problem of over-etching of the gate oxide layer is avoided.
In the above description, the technical details of patterning, etching, and the like of each layer are not described in detail. It will be appreciated by those skilled in the art that layers, regions, etc. of the desired shape may be formed by various technical means. In addition, in order to form the same structure, those skilled in the art can also design a method which is not exactly the same as the method described above. In addition, although the embodiments are described separately above, this does not mean that the measures in the embodiments cannot be used in advantageous combination.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims (10)

1. A method for removing a polysilicon sacrificial gate in a gate-last process is characterized in that a polysilicon etching agent is adopted to carry out wet etching on polysilicon to form a groove without polysilicon residue, and the polysilicon etching agent contains isopropanol.
2. The method for removing polysilicon sacrificial gate in gate last process as claimed in claim 1, wherein the polysilicon etchant further comprises an alkali solution, the alkali solution is ammonia or tetramethylammonium hydroxide, and the alkali solution is diluted with deionized water.
3. The method as claimed in claim 2, wherein the alkali solution, the isopropyl alcohol and the deionized water are respectively added into the chemical mixing tank and mixed uniformly, and then enter the etchant supply line.
4. The method as claimed in claim 2, wherein the alkali solution and the deionized water are added into the chemical mixing tank and mixed uniformly, and then enter the etchant supply line, and the isopropyl alcohol is added into the etchant supply line.
5. The method for removing the polysilicon sacrificial gate in the gate last process according to claim 3 or 4, wherein the chemicals in the chemical mixing tank sequentially enter the heater and the filter through the circulating pump and then circulate to the chemical mixing tank.
6. The method for removing the polysilicon sacrificial gate in the gate last process as claimed in claim 2, wherein the volume ratio of the alkali solution to the deionized water is 1: 2-1: 10; the volume of the isopropanol is 0.5-5% of the volume of the mixed solution of the alkali liquor and the water.
7. The method as claimed in claim 2, wherein the etching temperature of the etchant is 30-80 ℃.
8. The method as claimed in claim 2, wherein the flow rate of the etchant is 600-2500 ml/min.
9. A device for removing a polycrystalline silicon sacrificial gate in a gate-last process is characterized by comprising a chemical mixing tank, a chemical supply line, a chemical heating and filtering circulating line and an etchant supply line;
the upper part of the chemical mixing tank is provided with a whole or partial chemical supply line;
a medicine heating and filtering circulation pipeline is arranged on one side of the chemical mixing tank; the chemical agent is used for heating and filtering the chemical agent required by the polysilicon etching agent; along the circulation direction, a circulation pump, a heater and a filter are sequentially arranged on the medicine heating and filtering circulation pipeline;
an etchant supply line is arranged at the bottom of the chemical mixing tank and used for supplying etchant; when part of the chemical supply lines are arranged at the upper part of the chemical mixing tank, the rest of the chemical supply lines are arranged on the etching agent supply lines.
10. The apparatus for removing polysilicon sacrificial gate in gate last process as claimed in claim 9, wherein the chemical supply line comprises a deionized water supply line, a lye supply line and an isopropyl alcohol supply line;
the deionized water supply line, the alkali liquor supply line and the isopropanol supply line are respectively arranged at the upper part of the chemical mixing tank;
or the deionized water supply line and the alkali liquor supply line are respectively arranged at the upper part of the chemical mixing tank, and the isopropanol supply line is arranged on the etchant supply line.
CN202010943482.XA 2020-09-09 2020-09-09 Method and device for removing polycrystalline silicon sacrificial gate in gate-last process Pending CN114242585A (en)

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CN202010943482.XA CN114242585A (en) 2020-09-09 2020-09-09 Method and device for removing polycrystalline silicon sacrificial gate in gate-last process

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Application Number Priority Date Filing Date Title
CN202010943482.XA CN114242585A (en) 2020-09-09 2020-09-09 Method and device for removing polycrystalline silicon sacrificial gate in gate-last process

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CN114242585A true CN114242585A (en) 2022-03-25

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