CN108493205B - Method for eliminating reaction defect of aluminum pad and developing solution - Google Patents
Method for eliminating reaction defect of aluminum pad and developing solution Download PDFInfo
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- CN108493205B CN108493205B CN201810317807.6A CN201810317807A CN108493205B CN 108493205 B CN108493205 B CN 108493205B CN 201810317807 A CN201810317807 A CN 201810317807A CN 108493205 B CN108493205 B CN 108493205B
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 46
- 238000000034 method Methods 0.000 title claims abstract description 42
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 26
- 230000007547 defect Effects 0.000 title claims abstract description 19
- 238000006243 chemical reaction Methods 0.000 title claims abstract description 14
- 229920002120 photoresistant polymer Polymers 0.000 claims abstract description 58
- 238000005530 etching Methods 0.000 claims abstract description 36
- 230000004888 barrier function Effects 0.000 claims abstract description 20
- 239000000758 substrate Substances 0.000 claims abstract description 19
- 239000004065 semiconductor Substances 0.000 claims abstract description 16
- 238000000151 deposition Methods 0.000 claims abstract description 4
- 238000002360 preparation method Methods 0.000 claims abstract description 3
- MZLGASXMSKOWSE-UHFFFAOYSA-N tantalum nitride Chemical group [Ta]#N MZLGASXMSKOWSE-UHFFFAOYSA-N 0.000 claims description 8
- 238000000059 patterning Methods 0.000 claims description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 239000010703 silicon Substances 0.000 claims description 4
- 150000002576 ketones Chemical class 0.000 claims description 3
- 150000002632 lipids Chemical class 0.000 claims description 3
- 230000007935 neutral effect Effects 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims 1
- 239000000243 solution Substances 0.000 description 14
- 238000004519 manufacturing process Methods 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000012670 alkaline solution Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical group [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- CCEKAJIANROZEO-UHFFFAOYSA-N sulfluramid Chemical group CCNS(=O)(=O)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F CCEKAJIANROZEO-UHFFFAOYSA-N 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
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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
- G03F7/0035—Multiple processes, e.g. applying a further resist layer on an already in a previously step, processed pattern or textured surface
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- General Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Electromagnetism (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Solid State Image Pick-Up Elements (AREA)
Abstract
The invention provides a method for eliminating the reaction defect of an aluminum pad and a developing solution, which is applied to the preparation process of the aluminum pad of a CMOS image sensor, wherein a semiconductor substrate is provided, and the following steps are carried out on the semiconductor substrate: depositing an oxide layer on the surface of the semiconductor substrate; forming a groove structure at a preset position in the oxide layer; forming a contact hole at the bottom of the groove structure; covering an etching barrier layer above the oxide layer, and filling the etching barrier layer in the contact hole; forming an aluminum metal layer on the surface of the etching barrier layer; forming a photoresist layer on the surface of the aluminum metal layer; exposing the photoresist layer; developing the exposed photoresist layer by using a preset solution to form a process window; etching the aluminum metal layer and the etching barrier layer to form an aluminum pad; has the advantages that: on the premise of not increasing the number of layers and keeping the time of the existing flow, the developing process is optimized and the defects are prevented. Meanwhile, the yield can be improved, and the product is prevented from being scrapped.
Description
Technical Field
The invention relates to the field of semiconductor manufacturing, in particular to a method for eliminating reaction defects of an aluminum pad and a developing solution.
Background
In the manufacture process of a CMOS Image Sensor (CIS), an aluminum pad preparation process is included. The fabrication process typically includes forming an oxide layer on a silicon substrate. Next, a groove structure is formed in the oxide layer, and a contact hole is formed at the bottom of the groove structure. Next, a tantalum nitride layer is deposited on the oxide layer to fill the contact hole and cover the bottom and sidewall of the groove structure. Next, an aluminum metal layer is deposited on the tantalum nitride layer, and the aluminum metal layer is etched by using the photoresist as a mask to form an aluminum pad.
However, in the subsequent etching process, excessive tantalum nitride and oxide residues may occur, and finally, a ring shaped crater defect (volcano defect) as shown in fig. 1 is formed.
In order to avoid the above problems, it is now common to add an oxide layer on the aluminum pad to block the reaction between the developer and the aluminum, but the oxide on the aluminum pad must be opened subsequently, and a process is added, so that the product process is more complicated, and the time required for the whole process is increased.
Disclosure of Invention
In view of the above problems, the present invention provides a method for eliminating the reaction defect between an aluminum pad and a developer, which is applied to an aluminum pad fabrication process of a CMOS image sensor, wherein a semiconductor substrate is provided, and the following steps are performed on the semiconductor substrate:
step S1, depositing an oxide layer on the surface of the semiconductor substrate;
step S2, forming a trench structure at a first predetermined position in the oxide layer;
step S3, forming a contact hole at the bottom of the groove structure;
step S4, covering an etching barrier layer on the oxide layer, the bottom of the groove structure and the side wall of the groove structure, and filling the etching barrier layer in the contact hole;
step S5, forming an aluminum metal layer on the surface of the etching barrier layer;
step S6, forming a first photoresist layer on the surface of the aluminum metal layer;
step S7, exposing the first photoresist layer;
step S8, developing the exposed first photoresist layer with a predetermined solution to form a first process window;
and step S9, etching the aluminum metal layer and the etching barrier layer by taking the photoresist layer as a mask, removing the aluminum metal layer on the surface of the oxide layer and on the side wall of the groove structure, the etching barrier layer and the aluminum metal layer above the contact hole, and forming an aluminum pad.
Wherein the etching barrier layer is a tantalum nitride layer.
Wherein the step of forming the groove structure in step S2 includes:
step S21, forming a second photoresist layer on the oxide layer, patterning the second photoresist layer, and forming a second process window at a position where the groove structure is to be formed;
step S22, etching the oxide layer by taking the second photoresist layer as a mask to form the groove structure;
step S23, removing the second photoresist layer.
Wherein, in the step S3, the step of forming the contact hole includes:
step S31, forming a third photoresist layer on the surface of the oxide layer;
step S32, patterning the third photoresist layer, and forming a third process window in the contact hole forming region of the groove structure;
and step S33, etching the oxide layer by taking the third photoresist layer as a mask to form the contact hole.
Wherein the first photoresist layer and the barrier layer are removed after the step S9.
Wherein the thickness of the first photoresist layer is 20K-30K angstroms.
Wherein the critical dimension of the first photoresist layer is larger than 1 μm.
Wherein the predetermined solution is a lipid or ketone capable of dissolving the unexposed photoresist.
Wherein the semiconductor substrate is a silicon substrate.
Wherein the first photoresist layer is removed synchronously in the etching of the step S9, and the first photoresist layer is completely removed when the etching is finished
Has the advantages that: on the premise of not increasing the number of layers and maintaining the time of the existing flow, the developing process is optimized, the generation of defects is prevented, and the product yield is improved.
Drawings
FIG. 1 is a schematic diagram of a prior art annular crater defect;
FIG. 2 is a flow chart of an embodiment of a method for eliminating the reaction defect between an aluminum pad and a developer according to the present invention;
FIG. 3 is a flow chart of forming a recess structure according to an embodiment of the method for eliminating the reaction defect between an aluminum pad and a developer according to the present invention;
FIG. 4 is a flow chart of the contact hole formation in an embodiment of a method of eliminating the reaction defect of the aluminum pad and the developer solution according to the present invention;
FIGS. 5 a-5 c are schematic structural diagrams illustrating an embodiment of a method for eliminating the defect of the reaction between the aluminum pad and the developer according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.
As shown in fig. 2 and fig. 5 a-5 c, the present invention provides a method for eliminating the reaction defect between an aluminum pad and a developer, which is applied to the aluminum pad fabrication process of a CMOS image sensor, wherein a semiconductor substrate is provided, and the following steps are performed on the semiconductor substrate 1:
step S1, depositing an oxide layer 2 on the surface of the semiconductor substrate 1;
step S2, forming a groove structure 21 at a first predetermined position in the oxide layer 2;
step S3, forming a contact hole 22 at the bottom of the groove structure 21;
step S4, covering an etching barrier layer 3 on the oxide layer 2, the bottom of the groove structure 21, and the sidewall of the groove structure 21, and filling the contact hole with the etching barrier layer 3;
step S5, forming an aluminum metal layer 4 on the surface of the etching barrier layer 3;
step S6, forming a first photoresist layer 5 on the surface of the aluminum metal layer 4;
step S7, exposing the first photoresist layer 5;
step S8, developing the exposed first photoresist layer 5 with a predetermined solution to form a first process window;
step S9, etching the aluminum metal layer 4 and the etching stop layer 3 with the first photoresist layer 5 as a mask, and removing the aluminum metal layer 4, the etching stop layer 3, and the aluminum metal layer 4 above the contact hole on the surface of the oxide layer 2 and the sidewall of the groove structure 21 to form an aluminum pad.
The research shows that the aluminum can react with the alkaline developing solution to generate AlO2-And H2The large amount of gas generated may result in the formation of a ring crater defect. The chemical reaction formula is as follows:
secondly, AlO is generated due to the reactant2-Unlike the etch rate of Al, the etch results in a final tantalum nitride layer and partial oxide layer remaining. These residues block the optical signal of the CMOS Image Sensor (CIS), which affects the yield of the product.
According to the technical scheme, the neutral developing solution is used, so that the reaction of aluminum and the alkaline solution is avoided, partial residues of the tantalum nitride layer and the oxide layer caused by different surface etching rates are avoided, the developing process is optimized on the premise that the number of layers is not increased and the existing flow time is kept, the defects are prevented, and the product yield is improved.
In a preferred embodiment, the etch stop layer 4 is a tantalum nitride layer.
As shown in fig. 3 and fig. 5a to 5c, the step of forming the groove structure 21 in the step S2 includes:
step S21, forming a second photoresist layer on the oxide layer 2, patterning the second photoresist layer, and forming a second process window at a position where the groove structure 21 is to be formed;
step S22, etching the oxide layer with the second photoresist layer as a mask to form the groove structure 21;
step S23, removing the second photoresist layer.
As shown in fig. 4 and fig. 5a to 5c, in the step S3, the step of forming the contact hole includes:
step S31, forming a third photoresist layer on the surface of the oxide layer;
step S32, patterning the third photoresist layer, and forming a third process window in the contact hole forming region of the groove structure 21;
step S33, etching the oxide layer with the third photoresist layer as a mask to form the contact hole 22.
In the above technical solution, the first photoresist layer 5 may use a conventional I-Line photoresist, and the photoresist of the above type is a material well known to those skilled in the art, and therefore, details are not described again, and it should be noted that the I-Line photoresist used in this embodiment is only used to illustrate the feasibility of the technical solution, and does not limit the protection scope of the present invention.
In a preferred embodiment, the thickness of the first photoresist layer 5 is 20K-30K angstroms.
In the technical scheme, the thickness of the I-Line photoresist is generally between 7K and 30K angstroms, and the thickness of the I-Line photoresist is 20K to 30K angstroms, so that a better patterning effect can be ensured.
In a preferred embodiment, the critical dimension of the first photoresist layer 5 is larger than 1 μm.
In the technical scheme, when the critical dimension is larger than 1 mu m, the unexposed photoetching layer can be better removed.
In a preferred embodiment, the predetermined solution is a lipid or ketone that is capable of dissolving the unexposed photoresist.
In a preferred embodiment, the semiconductor substrate is a silicon substrate.
In summary, the alkaline developing solution used in the developing process is replaced by a neutral organic solution, so that the annular crater defect can be effectively avoided. The yield of the wafer is improved and the scrapping is reduced on the premise of not increasing the process time.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
Claims (9)
1. A method for eliminating the reaction defect of an aluminum pad and a developing solution is applied to the preparation process of the aluminum pad of a CMOS image sensor, and is characterized in that a semiconductor substrate is provided, and the following steps are carried out on the semiconductor substrate:
step S1, depositing an oxide layer on the surface of the semiconductor substrate;
step S2, forming a trench structure at a first predetermined position in the oxide layer;
step S3, forming a contact hole at the bottom of the groove structure;
step S4, covering an etching barrier layer on the oxide layer, the bottom of the groove structure and the side wall of the groove structure, and filling the etching barrier layer in the contact hole;
step S5, forming an aluminum metal layer on the surface of the etching barrier layer;
step S6, forming a first photoresist layer on the surface of the aluminum metal layer;
step S7, exposing the first photoresist layer;
step S8, developing the exposed first photoresist layer with a predetermined solution to form a first process window;
step S9, etching the aluminum metal layer and the etching barrier layer by taking the first photoresist layer as a mask, and removing the aluminum metal layer on the surface of the oxide layer and on the side wall of the groove structure, the etching barrier layer and the aluminum metal layer above the contact hole to form an aluminum pad;
the predetermined solution is a neutral solution, specifically a lipid or ketone substance capable of dissolving the unexposed photoresist.
2. The method of claim 1, wherein the etch stop layer is a tantalum nitride layer.
3. The method of claim 1, wherein the step of forming the groove structure in the step S2 comprises:
step S21, forming a second photoresist layer on the oxide layer, patterning the second photoresist layer, and forming a second process window at a position where the groove structure is to be formed;
step S22, etching the oxide layer by taking the second photoresist layer as a mask to form the groove structure;
step S23, removing the second photoresist layer.
4. The method according to claim 1, wherein in the step S3, the step of forming the contact hole comprises:
step S31, forming a third photoresist layer on the surface of the oxide layer;
step S32, patterning the third photoresist layer, and forming a third process window in the contact hole forming region of the groove structure;
and step S33, etching the oxide layer by taking the third photoresist layer as a mask to form the contact hole.
5. The method of claim 1, wherein the first photoresist layer and the barrier layer are removed after the step S9.
6. The method of claim 4, wherein the first photoresist layer has a thickness of 20K to 30K angstroms.
7. The method of claim 1, wherein the critical dimension of the first photoresist layer is greater than 1 μm.
8. The method of claim 1, wherein the semiconductor substrate is a silicon substrate.
9. The method of claim 1, wherein the first photoresist layer is removed simultaneously during the etching of step S9, and the first photoresist layer is completely removed at the end of the etching.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810317807.6A CN108493205B (en) | 2018-04-10 | 2018-04-10 | Method for eliminating reaction defect of aluminum pad and developing solution |
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| CN201810317807.6A CN108493205B (en) | 2018-04-10 | 2018-04-10 | Method for eliminating reaction defect of aluminum pad and developing solution |
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| CN108493205B true CN108493205B (en) | 2020-11-03 |
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Address after: 430205 No.18, Gaoxin 4th Road, Donghu Development Zone, Wuhan City, Hubei Province Patentee after: Wuhan Xinxin Integrated Circuit Co.,Ltd. Country or region after: China Address before: 430205 No.18, Gaoxin 4th Road, Donghu Development Zone, Wuhan City, Hubei Province Patentee before: Wuhan Xinxin Semiconductor Manufacturing Co.,Ltd. Country or region before: China |