CN111128694A - Etching method - Google Patents
Etching method Download PDFInfo
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- CN111128694A CN111128694A CN201811289425.3A CN201811289425A CN111128694A CN 111128694 A CN111128694 A CN 111128694A CN 201811289425 A CN201811289425 A CN 201811289425A CN 111128694 A CN111128694 A CN 111128694A
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- layer
- etched
- etching
- photoacid generator
- material layer
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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
- H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
- H01L21/033—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising inorganic layers
- H01L21/0334—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising inorganic layers characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane
- H01L21/0337—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising inorganic layers characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/70216—Mask projection systems
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Drying Of Semiconductors (AREA)
Abstract
The invention provides an etching method, which comprises the following steps: 1) providing a substrate; 2) forming a material layer to be etched on a substrate, wherein the upper surface of the material layer to be etched has a height difference; 3) forming an anti-reflection layer on the upper surface of the material layer to be etched; 4) forming a photoacid generator layer on the upper surface of the anti-reflection layer; 5) exposing the photoacid generator layer to light such that an acidified region is formed on top of the exposed region of the photoacid generator layer; 6) processing the acidized region to enable the acidized region to be converted into a mask layer; 7) and etching the photoacid generator layer, the anti-reflection layer and the material layer to be etched in sequence according to the mask layer. In the etching method, the mask layer and the photoacid generator layer positioned below the mask layer are jointly used as the etching mask layer, the thickness of the photoacid generator layer does not need to be too thick to achieve a good etching blocking effect, and the problems of reduced resolution, poor etching blocking effect and the like are solved.
Description
Technical Field
The invention belongs to the technical field of wafer-level three-dimensional packaging, and particularly relates to an etching method.
Background
In the conventional semiconductor process, the upper surface of the material layer to be etched formed on the substrate has a height difference for various reasons, i.e., the upper surface of one part of the material layer to be etched is stepped higher than the height of the other part of the material layer to be etched. However, if the photoresist layer is directly formed on the upper surface of the material layer to be etched for photolithography, the existence of the step may cause many problems, such as defocusing (defocus), insufficient resolution (sub-resolution) in the photolithography process, and etch-stop effect (etch-prevention) of the photoresist in the etching process; particularly, as the process nodes are reduced and reach sub-28 nm nodes, the influence of steps is more obvious.
An existing improvement method is to form an anti-reflection layer on the upper surface of a material layer to be etched having a step, and the upper surface of the anti-reflection layer is a plane to offset the step of the material layer to be etched. However, this method is only suitable for the case that the step height of the material layer to be etched is small, and when the step height of the material layer to be etched exceeds a certain value, a thicker anti-reflection layer is required to maintain the flatness of the surface for forming the material layer to be etched, that is, a thicker anti-reflection layer is required to ensure the flatness of the upper surface of the anti-reflection layer. The photoresist is consumed in the process of opening the anti-reflection layer by etching, the thicker anti-reflection layer necessarily needs the thicker photoresist, and otherwise, the etching blocking effect of the photoresist in the etching process cannot be ensured; when the size of the pattern to be formed is small, the resolution is reduced due to the thick photoresist layer, thereby affecting the accuracy of the process.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide an etching method for solving the above-mentioned problems in the prior art.
In order to achieve the above and other related objects, the present invention provides an etching method, including the steps of:
1) providing a substrate;
2) forming a material layer to be etched on the substrate, wherein the upper surface of the material layer to be etched has a height difference;
3) forming an anti-reflection layer on the upper surface of the material layer to be etched;
4) forming a photoacid generator layer on the upper surface of the anti-reflection layer;
5) exposing the photoacid generator layer to light such that an acidified region is formed on top of the exposed region of the photoacid generator layer;
6) processing the acidized region to enable the acidized region to be converted into a mask layer;
7) and etching the photoacid generator layer, the anti-reflection layer and the material layer to be etched in sequence according to the mask layer.
Optionally, the following steps are further included between step 1) and step 2):
forming an etching barrier layer on the upper surface of the substrate;
forming a pattern structure on the upper surface of the etching barrier layer;
in the step 2), the material layer to be etched is formed on the upper surface of the etching barrier layer, and the etching material layer covers the pattern structure.
Optionally, the material layer to be etched comprises a region to be etched and a non-etched region, and the pattern structure is located in the non-etched region; the height of the upper surface of the non-etching area of the material layer to be etched is higher than that of the upper surface of the area of the material layer to be etched.
Optionally, step 6) comprises the steps of:
6-1) baking the acidified region to allow the acidified region to catalytically react to form a polymer ionically reactive with the silicon-containing gas;
6-2) reacting the polymer with a silicon-containing gas to form the mask layer.
Optionally, the temperature for baking the acidified region in step 6-1)) is 100 ℃ to 150 ℃.
Optionally, the silicon-containing gas comprises monosilane.
Optionally, the mask layer comprises a silicon oxide layer.
Optionally, the photoacid generator layer, the anti-reflection layer, and the material layer to be etched are sequentially etched by using a reactive ion etching process.
Optionally, the thickness of the acidified region formed in step 5) and the thickness of the mask layer formed in step 6) are both less than the thickness of the photoacid generator layer.
Optionally, after step 7), the method further comprises the step of removing the mask layer, the photoacid generator layer and the antireflection layer.
As described above, the etching method of the present invention has the following beneficial effects:
according to the etching method, the patterned mask layer is formed on the upper portion of the photoacid generator layer, the mask layer and the photoacid generator layer below the mask layer are used as the etching mask layer, namely a hard mask is added, when a material layer to be etched with a high step is etched, the thickness of the photoacid generator layer does not need to be too thick, a good etching blocking effect can be achieved, and the problems of low resolution, poor etching blocking effect and the like cannot exist.
Drawings
Fig. 1 shows a flow chart of an etching method provided by the present invention.
Fig. 2 to 12 are schematic cross-sectional structures of structures obtained in the steps of the etching method according to the present invention.
Description of the element reference numerals
10 base
11 layer of material to be etched
111 region to be etched
112 non-etched area
12 anti-reflection layer
13 photo acid generator layer
14 acidizing region
15 mask layer
16 etch stop layer
17 pattern structure
18 Polymer
19 photo mask
20 light ray
S1-S7
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.
Please refer to fig. 1 to 12. It should be noted that the drawings provided in the present embodiment are only schematic and illustrate the basic idea of the present invention, and although the drawings only show the components related to the present invention and are not drawn according to the number, shape and size of the components in actual implementation, the form, quantity and proportion of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.
Referring to fig. 1, the present invention provides an etching method, including the following steps:
1) providing a substrate;
2) forming a material layer to be etched on the substrate, wherein the upper surface of the material layer to be etched has a height difference;
3) forming an anti-reflection layer on the upper surface of the material layer to be etched;
4) forming a photoacid generator layer on the upper surface of the anti-reflection layer;
5) exposing the photoacid generator layer to light such that an acidified region is formed on top of the exposed region of the photoacid generator layer;
6) processing the acidized region to enable the acidized region to be converted into a mask layer;
7) and etching the photoacid generator layer, the anti-reflection layer and the material layer to be etched in sequence according to the mask layer.
In step 1), please refer to step S1 in fig. 1 and fig. 2, a substrate 10 is provided.
By way of example, the substrate 10 may be any substrate that can support the material layer 11 to be etched later, such as a semiconductor substrate, a glass substrate, and the like, and preferably, the substrate 10 may include, but is not limited to, a semiconductor substrate, and the substrate 10 may be a bare wafer or a wafer with a device structure formed therein, and the like.
As an example, as shown in fig. 3, the following steps are further included between step 1) and step 2):
forming an etching barrier layer 16 on the upper surface of the substrate 10;
a patterned structure 14 is formed on the upper surface of the etch stop layer 16.
As an example, the etch stop layer 16 may be a material layer having a high selectivity ratio with any material layer to be etched that is formed later, that is, under the same etching condition, the etch removal rate of the material layer to be etched is much greater than the etch removal rate of the etch stop layer 16. The material of the etch stop layer 16 may be selected according to the material of the material layer to be etched, and when the material layer to be etched is a polysilicon layer, the etch stop layer 16 may include, but is not limited to, a titanium nitride layer.
In step 2), referring to step S2 in fig. 1 and fig. 4, a material layer 11 to be etched is formed on the substrate 10, and the upper surface of the material layer 11 to be etched has a height difference.
It should be noted that, when the etch stop layer 16 and the pattern structure 17 are not formed on the substrate 10, the material layer to be etched 11 may be directly formed on the upper surface of the substrate 10. At this time, a structure such as a groove may be formed in the substrate 10, so that the material layer 11 to be etched is directly formed on the upper surface of the substrate 10, and then the upper surface of the material layer 11 to be etched has a height difference.
It should be further noted that, when the etching stop layer 16 and the pattern structure 17 are formed on the upper surface of the substrate 10, the material layer 11 to be etched is formed on the upper surface of the etching stop layer 16, and the etching material layer 11 covers the pattern structure 17, as shown in fig. 4.
As an example, the material layer to be etched 11 includes an area to be etched 111 and an area not to be etched 112, and the pattern structure 17 is located in the area not to be etched 112; due to the fact that the pattern structure 17 is formed in the non-etching region 112, the height of the upper surface of the non-etching region 112 of the material layer 11 to be etched is higher than the height of the upper surface of the region 111 of the material layer 11 to be etched, that is, the upper surface of the material layer 11 to be etched is in a step-shaped abrupt change at the boundary of the etching region 111 and the non-etching region 112.
As an example, the material layer to be etched 11 may include a polysilicon layer or a dielectric layer, etc.
In step 3), referring to step S3 in fig. 1 and fig. 5, an anti-reflection layer (BARC)12 is formed on the upper surface of the material layer 11 to be etched.
As an example, after the anti-reflection layer 12 is formed on the upper surface of the material layer 11 to be etched, the maximum thickness of the anti-reflection layer 12 is greater than the height difference of the upper surface of the material layer 11 to be etched, so that the upper surface of the anti-reflection layer 12 is a plane.
In step 4), referring to step S4 in fig. 1 and fig. 6, a photo-acid generator layer 13 is formed on the upper surface of the anti-reflection layer 12.
As an example, the material of the photoacid generator layer 13 is a photosensitive compound that decomposes under irradiation of light to generate an acid (H)+) During the post exposure bake process, the exposed regions may undergo a catalytic reaction.
In step 5), referring to step S5 in fig. 1 and fig. 7, the photoacid generator layer 13 is exposed to form an acidified region 14 on top of the exposed region of the photoacid generator layer 13.
As an example, a photomask 19 is placed above the photoacid generator layer 13, an opening is formed in the photomask 19, and an exposed region below the opening is an exposed region of the photoacid generator layer 13; the photoacid generator layer 13 is exposed using exposure light 20 under the shadow of the photomask 19. In the exposure process, since the exposure light 20 does not reach the region blocked by the photomask 19, only the region not blocked by the photomask 19 (i.e., the exposed region of the photoacid generator layer 13) is exposed to the exposure light 20 to generate the acidified region 14.
As an example, the thickness of the acidified region 14 is less than the thickness of the photoacid generator layer 13.
In step 6), referring to step S6 in fig. 1 and fig. 8 to 9, the acidified region 14 is processed to convert the acidified region 14 into the mask layer 15.
As an example, step 6) comprises the following steps:
6-1) baking the acidified region to allow the acidified region to catalytically react to form a polymer ionically reactive with the silicon-containing gas;
6-2) reacting the polymer with a silicon-containing gas to form the mask layer.
As an example, in step 6-1), the structure obtained in step 5) may be placed in a baking device (such as a baking oven) to be baked, so that the acidified region 14 undergoes a catalytic reaction, and the temperature of baking the acidified region 14 may be 100 ℃ to 150 ℃.
As an example, the thickness of the polymer 18 is less than the thickness of the photoacid generator layer 13.
As an example, in step 6-2), the structure obtained in step 6-1) may be placed in a reaction chamber, and a silicon-containing gas may be introduced into the reaction chamber under reaction conditions to perform a reaction.
By way of example, the silicon-containing gas may include, but is not limited to, monosilane.
By way of example, the mask layer 15 may include, but is not limited to, a silicon oxide layer.
As an example, the thickness of the mask layer 15 is smaller than the thickness of the photoacid generator layer 13.
In step 7), referring to step S7 in fig. 1 and fig. 10 to 11, the photo-acid generator layer 13, the anti-reflection layer 12 and the material layer to be etched 11 are sequentially etched according to the mask layer 15.
As an example, the photo acid generator layer 13, the anti-reflection layer 12 and the material layer to be etched 11 are sequentially etched by, but not limited to, a Reactive Ion Etching (RIE) process. In the etching process, the photoacid generator layer 13, the anti-reflection layer 12 and the material layer 11 to be etched covered by the mask layer 15 are retained, and the photoacid generator layer 13, the anti-reflection layer 12 and the material layer 11 to be etched exposed by the mask layer 15 are etched and removed. In the etching process, the mask layer 15 and the reserved photoacid generator layer 13 are jointly used as an etching mask layer, the existence of the mask layer 15 is equivalent to the addition of a hard mask, when the material layer 11 to be etched with a high step is etched, the thickness of the photoacid generator layer 13 does not need to be too thick so as to achieve a good etching blocking effect, and the problems of reduced resolution, poor etching blocking effect and the like are avoided.
As an example, as shown in fig. 12, after the step 7), a step of removing the mask layer 15, the photoacid generator layer 13, and the anti-reflection layer 12 is further included. The specific method for removing the mask layer 15, the photoacid generator layer 13, and the anti-reflective layer 12 is known to those skilled in the art and will not be described herein.
In summary, the etching method of the present invention includes the following steps: 1) providing a substrate; 2) forming a material layer to be etched on the substrate, wherein the upper surface of the material layer to be etched has a height difference; 3) forming an anti-reflection layer on the upper surface of the material layer to be etched; 4) forming a photoacid generator layer on the upper surface of the anti-reflection layer; 5) exposing the photoacid generator layer to light such that an acidified region is formed on top of the exposed region of the photoacid generator layer; 6) processing the acidized region to enable the acidized region to be converted into a mask layer; 7) and etching the photoacid generator layer, the anti-reflection layer and the material layer to be etched in sequence according to the mask layer. According to the etching method, the patterned mask layer is formed on the upper portion of the photoacid generator layer, the mask layer and the photoacid generator layer below the mask layer are used as the etching mask layer, namely a hard mask is added, when a material layer to be etched with a high step is etched, the thickness of the photoacid generator layer does not need to be too thick, a good etching blocking effect can be achieved, and the problems of low resolution, poor etching blocking effect and the like cannot exist.
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 (10)
1. An etching method is characterized by comprising the following steps:
1) providing a substrate;
2) forming a material layer to be etched on the substrate, wherein the upper surface of the material layer to be etched has a height difference;
3) forming an anti-reflection layer on the upper surface of the material layer to be etched;
4) forming a photoacid generator layer on the upper surface of the anti-reflection layer;
5) exposing the photoacid generator layer to light such that an acidified region is formed on top of the exposed region of the photoacid generator layer;
6) processing the acidized region to enable the acidized region to be converted into a mask layer;
7) and etching the photoacid generator layer, the anti-reflection layer and the material layer to be etched in sequence according to the mask layer.
2. The etching method according to claim 1, further comprising the following steps between the step 1) and the step 2):
forming an etching barrier layer on the upper surface of the substrate;
forming a pattern structure on the upper surface of the etching barrier layer;
in the step 2), the material layer to be etched is formed on the upper surface of the etching barrier layer, and the etching material layer covers the pattern structure.
3. The etching method according to claim 2, wherein the material layer to be etched comprises an area to be etched and a non-etched area, and the pattern structure is located in the non-etched area; the height of the upper surface of the non-etching area of the material layer to be etched is higher than that of the upper surface of the area of the material layer to be etched.
4. Etching method according to claim 1, characterized in that step 6) comprises the steps of:
6-1) baking the acidified region to allow the acidified region to catalytically react to form a polymer ionically reactive with the silicon-containing gas;
6-2) reacting the polymer with a silicon-containing gas to form the mask layer.
5. Etching method according to claim 4, wherein the temperature for baking the acidified region in step 6-1)) is 100 ℃ to 150 ℃.
6. The etching method of claim 4, wherein the silicon-containing gas comprises monosilane.
7. The etching method according to claim 4, wherein the mask layer comprises a silicon oxide layer.
8. The etching method according to claim 4, wherein the photoacid generator layer, the anti-reflection layer, and the material layer to be etched are sequentially etched by a reactive ion etching process.
9. The etching method according to claim 1, wherein a thickness of the acidified region formed in step 5) and a thickness of the mask layer formed in step 6) are smaller than a thickness of the photoacid generator layer.
10. The etching method according to claim 1, further comprising a step of removing the mask layer, the photoacid generator layer, and the anti-reflection layer after step 7).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811289425.3A CN111128694A (en) | 2018-10-31 | 2018-10-31 | Etching method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811289425.3A CN111128694A (en) | 2018-10-31 | 2018-10-31 | Etching method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111128694A true CN111128694A (en) | 2020-05-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811289425.3A Withdrawn CN111128694A (en) | 2018-10-31 | 2018-10-31 | Etching method |
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| Country | Link |
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| CN (1) | CN111128694A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023037746A1 (en) * | 2021-09-07 | 2023-03-16 | 株式会社Ｓｃｒｅｅｎホールディングス | Substrate processing apparatus and substrate processing method |
-
2018
- 2018-10-31 CN CN201811289425.3A patent/CN111128694A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023037746A1 (en) * | 2021-09-07 | 2023-03-16 | 株式会社Ｓｃｒｅｅｎホールディングス | Substrate processing apparatus and substrate processing method |
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