CN117219648A - Etching method applied to back-end process - Google Patents
Etching method applied to back-end process Download PDFInfo
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- CN117219648A CN117219648A CN202311281572.7A CN202311281572A CN117219648A CN 117219648 A CN117219648 A CN 117219648A CN 202311281572 A CN202311281572 A CN 202311281572A CN 117219648 A CN117219648 A CN 117219648A
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- Prior art keywords
- layer
- aluminum
- etching
- hard mask
- target area
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- 238000000034 method Methods 0.000 title claims abstract description 46
- 238000005530 etching Methods 0.000 title claims abstract description 45
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 52
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 52
- 239000000460 chlorine Substances 0.000 claims abstract description 22
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000010937 tungsten Substances 0.000 claims abstract description 22
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 22
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 21
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 21
- FAQYAMRNWDIXMY-UHFFFAOYSA-N trichloroborane Chemical compound ClB(Cl)Cl FAQYAMRNWDIXMY-UHFFFAOYSA-N 0.000 claims abstract description 20
- 239000012495 reaction gas Substances 0.000 claims abstract description 13
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229920002120 photoresistant polymer Polymers 0.000 claims abstract description 12
- 239000000758 substrate Substances 0.000 claims abstract description 8
- 238000001259 photo etching Methods 0.000 claims abstract description 4
- 239000010410 layer Substances 0.000 claims description 90
- 239000012790 adhesive layer Substances 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000004411 aluminium Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 230000000295 complement effect Effects 0.000 description 2
- 239000003292 glue Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
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- Drying Of Semiconductors (AREA)
Abstract
The application discloses an etching method applied to a back-end process, which comprises the following steps: forming a hard mask layer on the top adhesion layer, the top adhesion layer being formed on the aluminum layer, the aluminum layer being formed on the bottom adhesion layer, the bottom adhesion layer being formed on the tungsten layer, the tungsten layer being formed over the substrate; covering a photoresist on the hard mask layer through a photoetching process, exposing other areas except a target area, wherein the target area is an area corresponding to the liner structure; removing the top adhesion layer and the hard mask layer in areas other than the target area; carrying out first aluminum etching, wherein the reaction gas introduced in the etching process comprises boron trichloride and chlorine; performing secondary aluminum etching to remove the aluminum layer and the bottom bonding layer in other areas except the target area, wherein the reaction gas introduced in the etching process comprises boron trichloride, chlorine and methane; the photoresist and the remaining hard mask layer are removed.
Description
Technical Field
The application relates to the technical field of semiconductor integrated circuit manufacturing, in particular to an etching method applied to a back-end process.
Background
In the semiconductor integrated circuit manufacturing process, a pad structure formed in a back end of line (BEOL) is generally made of aluminum (Al), and the pad structure is generally a sandwich structure including, in order, a top adhesion layer (glue layer), an aluminum layer, and a bottom adhesion layer (glue layer), wherein the adhesion layer may include titanium nitride (TiN) and/or titanium (Ti).
In the related art, for some semiconductor device products, such as backside illuminated complementary metal oxide semiconductor image sensor (backside illumination complementary metal-oxide semiconductor contact image sensor, BSI CIS) devices, a liner structure may be formed by etching through a photolithography process after sequentially forming a bottom adhesion layer, an aluminum layer, and a top adhesion layer over a substrate.
However, in the etching method provided in the related art, the reaction gas introduced in the etching process includes boron trichloride and chlorine, so that the etching rate is too high, and overetching of the metal tungsten (W) layer below the bottom bonding layer is easily caused, which affects the yield of the product.
Disclosure of Invention
The application provides an etching method applied to a back-end process, which can solve the problem that the aluminum etching method provided in the related art is easy to cause over-etching of tungsten below an adhesive layer, and comprises the following steps:
forming a hard mask layer on a top adhesion layer, the top adhesion layer being formed on an aluminum layer, the aluminum layer being formed on a bottom adhesion layer, the bottom adhesion layer being formed on a tungsten layer, the tungsten layer being formed over a substrate;
covering a photoresist on the hard mask layer through a photoetching process, and exposing other areas except for a target area, wherein the target area is an area corresponding to a liner structure;
removing the top adhesive layer and the hard mask layer in other areas except the target area;
carrying out first aluminum etching, wherein the reaction gas introduced in the etching process comprises boron trichloride and chlorine;
performing secondary aluminum etching to remove the aluminum layer and the bottom bonding layer of other areas except the target area, wherein the reaction gas introduced in the etching process comprises boron trichloride, chlorine and methane;
the photoresist and the remaining hard mask layer are removed.
In some embodiments, the flow ratio of boron trichloride to chlorine is 1:1 during the first aluminum etch.
In some embodiments, the power ranges from 100 watts to 600 watts during the first aluminum etch.
In some embodiments, the flow ratio of boron trichloride to chlorine is 2:1 during the second aluminum etch.
In some embodiments, the source power ranges from 500 watts to 1500 watts during the second aluminum etch.
In some embodiments, the bias power ranges from 0 watts to 150 watts during the second aluminum etch.
In some embodiments, the pressure ranges from 15 mtorr to 25 mtorr during the second aluminum etch.
The technical scheme of the application at least comprises the following advantages:
through in the back end of the line, through twice etching metal aluminium layer, the reaction gas that lets in the aluminium etching of first time includes boron trichloride and chlorine, and the reaction gas that lets in the aluminium etching of second time includes boron trichloride, chlorine and methane, can reduce the loss of the tungsten layer of bottom adhesive layer below in the etching process, improve the yield of device product to a certain extent.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present application, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of an etching method applied in a back-end-of-line process according to an exemplary embodiment of the present application;
fig. 2 to 3 are schematic diagrams illustrating an etching method applied to a back-end process according to an exemplary embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made more apparent and fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the application are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In the description of the present application, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, or can be communicated inside the two components, or can be connected wirelessly or in a wired way. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.
In addition, the technical features of the different embodiments of the present application described below may be combined with each other as long as they do not collide with each other.
Referring to fig. 1, a flowchart of an etching method applied in a back-end process according to an exemplary embodiment of the present application is shown, where the method may be applied in a BSI CIS device manufacturing process, as shown in fig. 1, and the method includes:
step S1, forming a hard mask layer on a top bonding layer, wherein the top bonding layer is formed on an aluminum layer, the aluminum layer is formed on a bottom bonding layer, the bottom bonding layer is formed on a tungsten layer, and the tungsten layer is formed above a substrate.
And S2, covering the photoresist on the hard mask layer through a photoetching process, and exposing other areas except for a target area, wherein the target area is an area corresponding to the liner structure.
Referring to fig. 2, a schematic cross-sectional view is shown after a photoresist is coated on the hard mask layer. As shown in fig. 2, a tungsten layer 220 is formed over a substrate 210, a bottom adhesion layer 231 is formed on the tungsten layer 220, an aluminum layer 232 is formed on the bottom adhesion layer 231, and a top adhesion layer 233, a hard mask layer 240 and a photoresist 300 are formed on the aluminum layer 232, wherein a region covered by the photoresist 300 is a target region. Wherein the hard mask layer 240 includes a silicon oxynitride (SiON) layer and silicon dioxide (SiO) 2 ) The layers, top adhesion layer 233 and bottom adhesion layer 231 include a titanium nitride layer and/or a titanium layer.
An adhesion layer 211, a metal barrier layer 212, and a tungsten seed layer 213 are formed between the substrate 210 and the tungsten layer 220 in this order from top to bottom. The substrate 210 is also formed therein with a trench 201 and a via 202, and an adhesion layer 211, a metal barrier layer 212, a tungsten seed layer 213, and a tungsten layer 220 in the via 202 constitute a contact hole (via).
And S3, removing the top adhesive layer and the hard mask layer in other areas except the target area.
And S4, performing first aluminum etching, wherein the reaction gas introduced in the etching process comprises boron trichloride and chlorine.
Wherein during the first aluminum etching, boron trichloride (BCl) 3 ) And chlorine (Cl) 2 ) The flow ratio of the aluminum etching solution is 1:1, the power (power) is 100 watts (W) to 600W, the first aluminum etching speed is high, and most of the aluminum layer and the bottom bonding layer can be removed.
And S5, performing secondary aluminum etching to remove the aluminum layer and the bottom bonding layer in other areas except the target area, wherein the reaction gas introduced in the etching process comprises boron trichloride, chlorine and methane.
In the second aluminum etching process, the flow ratio of boron trichloride to chlorine is 2:1, the value range of source power (source power) is 500-1500 watts, the value range of bias power (bias power) is 0-150 watts, the value range of pressure is 15 millitorr (mTorr) to 25 millitorr, the first aluminum etching speed is slower, and meanwhile, the chlorine is introduced, the chlorine can react with tungsten to protect the side wall and the surface of the tungsten layer, so that over etching of the tungsten layer is avoided.
And S6, removing the photoresist and the residual hard mask layer.
Referring to fig. 3, a schematic cross-sectional view is shown after two aluminum etches and removes the photoresist and remaining hard mask layer. Illustratively, as shown in fig. 3, the aluminum layer and the bottom adhesion layer are removed in areas other than the target area, and the tungsten layer is not over-etched.
In summary, in the embodiment of the application, in the back-end process, the metal aluminum layer is etched twice, the reaction gas introduced in the first aluminum etching includes boron trichloride and chlorine, and the reaction gas introduced in the second aluminum etching includes boron trichloride, chlorine and methane, so that the loss of the tungsten layer below the bottom bonding layer in the etching process can be reduced, and the yield of device products is improved to a certain extent.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the application.
Claims (7)
1. An etching method applied to a back-end process, comprising:
forming a hard mask layer on a top adhesion layer, the top adhesion layer being formed on an aluminum layer, the aluminum layer being formed on a bottom adhesion layer, the bottom adhesion layer being formed on a tungsten layer, the tungsten layer being formed over a substrate;
covering a photoresist on the hard mask layer through a photoetching process, and exposing other areas except for a target area, wherein the target area is an area corresponding to a liner structure;
removing the top adhesive layer and the hard mask layer in other areas except the target area;
carrying out first aluminum etching, wherein the reaction gas introduced in the etching process comprises boron trichloride and chlorine;
performing secondary aluminum etching to remove the aluminum layer and the bottom bonding layer of other areas except the target area, wherein the reaction gas introduced in the etching process comprises boron trichloride, chlorine and methane;
the photoresist and the remaining hard mask layer are removed.
2. The method of claim 1, wherein the flow ratio of boron trichloride to chlorine is 1:1 during the first aluminum etch.
3. The method of claim 2, wherein the power is in the range of 100 watts to 600 watts during the first aluminum etch.
4. The method of claim 2, wherein the flow ratio of boron trichloride to chlorine is 2:1 during the second aluminum etch.
5. The method of claim 4, wherein the source power is in the range of 500 watts to 1500 watts during the second aluminum etch.
6. The method of claim 5, wherein the bias power has a value in the range of 0 watts to 150 watts during the second aluminum etch.
7. The method of claim 6, wherein the pressure ranges from 15 mtorr to 25 mtorr during the second aluminum etching.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311281572.7A CN117219648A (en) | 2023-09-28 | 2023-09-28 | Etching method applied to back-end process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311281572.7A CN117219648A (en) | 2023-09-28 | 2023-09-28 | Etching method applied to back-end process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117219648A true CN117219648A (en) | 2023-12-12 |
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ID=89037009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311281572.7A Pending CN117219648A (en) | 2023-09-28 | 2023-09-28 | Etching method applied to back-end process |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117219648A (en) |
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2023
- 2023-09-28 CN CN202311281572.7A patent/CN117219648A/en active Pending
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