CN111968914B - Thick aluminum etching method - Google Patents

Thick aluminum etching method Download PDF

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CN111968914B
CN111968914B CN201910419724.2A CN201910419724A CN111968914B CN 111968914 B CN111968914 B CN 111968914B CN 201910419724 A CN201910419724 A CN 201910419724A CN 111968914 B CN111968914 B CN 111968914B
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thick aluminum
etching
buffer layer
boron trichloride
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CN111968914A (en
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朱文明
黄仁瑞
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CSMC Technologies Fab2 Co Ltd
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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
    • H01L21/32135—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 vapour etching only
    • H01L21/32136—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 vapour etching only using plasmas
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/02—Local etching
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/10—Etching compositions
    • C23F1/12—Gaseous compositions
    • 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
    • H01L21/32139—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer using masks
    • 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
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors

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Abstract

The invention relates to a thick aluminum etching method, which comprises the following steps: forming a metal interconnection structure on the wafer, wherein the metal interconnection structure comprises a first buffer layer, a thick aluminum layer and a second buffer layer which are sequentially arranged on the wafer, and a photoresist layer is formed on the second buffer layer; patterning the photoresist layer, and etching the second buffer layer according to the pattern of the photoresist layer; etching the thick aluminum layer with the first proportional thickness by using nitrogen, chlorine and boron trichloride; keeping the pressure of the cavity unchanged, reducing the flow of nitrogen and boron trichloride, and etching the remaining thick aluminum layer with the thickness of the second proportion and the first buffer layer. By comprehensively controlling parameters such as cavity pressure, reaction gas types and flow, the etching rate of the reaction gas to the photoresist is reduced, and finally the selection ratio of the thick aluminum layer to the photoresist layer reaches 3-3.5.

Description

Thick aluminum etching method
Technical Field
The invention relates to the field of semiconductors, in particular to a thick aluminum etching method.
Background
In semiconductor devices, aluminum is the most common interconnect metal material. When forming the metal interconnection line of the semiconductor device, an etching technology is adopted to etch aluminum to form the connecting line. Generally, in order to ensure the line precision of the connecting line, the aluminum line is etched by adopting a dry etching technology, and the photoresist is used as a mask for etching.
The inventor finds that the selection ratio of aluminum to high-resolution photoresist in the traditional process is usually less than 2, and the effective residual photoresist thickness cannot be achieved by using the photoresist as an etching barrier layer, so that a semiconductor device cannot meet the process requirement. It may be considered to form a hard mask layer as a supplementary barrier layer prior to forming the photoresist to prevent photoresist starvation. However, the addition of one more hard mask layer not only makes the fabrication process complicated, but also increases the cost of the semiconductor device.
Disclosure of Invention
Therefore, it is necessary to provide a thick aluminum etching method for solving the problem that the semiconductor device cannot meet the process requirements due to the small selection of aluminum and photoresist.
A thick aluminum etching method comprises the following steps:
forming a metal interconnection structure on a wafer, wherein the metal interconnection structure comprises a first buffer layer, a thick aluminum layer and a second buffer layer which are sequentially arranged on the wafer, and a photoresist layer is formed on the second buffer layer;
patterning the photoresist layer, and etching the second buffer layer according to the pattern of the photoresist layer;
etching the thick aluminum layer with a first proportional thickness by using nitrogen, chlorine and boron trichloride;
and keeping the pressure of the cavity unchanged, reducing the flow of the nitrogen and the boron trichloride, and etching the thick aluminum layer and the first buffer layer with the residual second proportional thickness, wherein the second proportional thickness is smaller than the first proportional thickness.
In one embodiment, the method further comprises the step of forming an anti-reflection layer on the second buffer layer, wherein the photoresist layer is formed on the anti-reflection layer;
the patterning the photoresist layer and etching the second buffer layer according to the pattern of the photoresist layer include:
and patterning the photoresist layer, and sequentially etching the anti-reflection layer and the second buffer layer according to the pattern of the photoresist layer.
In one embodiment, the etching gas for etching the anti-reflection layer is chlorine and trifluoromethane, and the flow ratio of the chlorine to the trifluoromethane is 6: 1-6.5: 1;
the etching gas for etching the second buffer layer is chlorine and boron trichloride, and the flow ratio of the chlorine to the boron trichloride is 0.9: 1-1: 1.
In one embodiment, when the thick aluminum layer with the first proportional thickness is etched, the cavity pressure of the reaction chamber is 12mTorr to 20mTorr, the flow rate of nitrogen is 12sccm, and the flow rate ratio of chlorine to boron trichloride is 1:1.
In one embodiment, the flow rates of the chlorine gas and the boron trichloride are both 85sccm to 90 sccm.
In one embodiment, the reducing the flow of the nitrogen gas and the boron trichloride to etch the remaining thick aluminum layer and the first buffer layer with the second proportional thickness includes:
and reducing the flow of the nitrogen and the boron trichloride until the gas flow of the nitrogen is 7 sccm-9 sccm, the gas flow of the boron trichloride is 70 sccm-90 sccm, and etching the thick aluminum layer with the rest second proportional thickness and the first buffer layer.
In one embodiment, the first proportional thickness is 90% to 95% of the thick aluminum layer and the second proportional thickness is 5% to 10% of the thick aluminum layer.
In one embodiment, the wafer further comprises an insulating layer;
reducing the nitrogen gas with the flow of boron trichloride, the thick aluminium layer that the remaining second proportion thickness of sculpture still includes after the first buffer layer:
exchanging the proportion of the chlorine gas and the boron trichloride, wherein the flow proportion of the chlorine gas and the boron trichloride is 1:1.2, reducing the flow of the nitrogen gas, and etching the insulating layer.
In one embodiment, the first buffer layer and the second buffer layer comprise a titanium metal layer and/or a titanium nitride layer; when the first buffer layer comprises the metal titanium layer and the titanium nitride layer, the metal titanium layer is arranged on the titanium nitride layer, and the thick aluminum layer is arranged on the metal titanium layer;
when the second buffer layer comprises the metal titanium layer and the titanium nitride layer, the metal titanium layer is arranged on the thick aluminum layer, and the titanium nitride layer is arranged on the metal titanium layer.
In one embodiment, the thickness of the thick aluminum layer is greater than or equal to 0.46um to 3 um.
According to the method, in the main etching process of the thick aluminum layer, the etching rate of the reaction gas to the metal aluminum is higher than that to the photoresist by controlling the flow of the reaction gas. By adopting an end point detection mechanism, when the etching end point of the thick aluminum layer is approached, the flow of reaction gas is reduced, the reaction rate can be reduced, and the selection ratio of the thick aluminum layer to the photoresist layer can be improved by adjusting parameters.
Drawings
FIG. 1 is a flowchart of a thick aluminum etching method according to an embodiment of the present application;
fig. 2A to 2C are schematic cross-sectional views of the semiconductor device fabricated according to the method of fig. 1.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
As described in the background art, the selection ratio of aluminum and photoresist in the conventional technology is low, so that the residual photoresist thickness cannot meet the process requirements when the photoresist is used as an etching barrier layer, and the prepared semiconductor device cannot meet the requirements. Typically, a hard mask layer is formed as a supplemental barrier layer before the photoresist is formed in order to make the remaining photoresist thick to meet the process requirements. However, the addition of a hard mask layer makes the fabrication process more complicated, increases the chip cost, and is not suitable for mass production.
In view of the above problems, an embodiment of the present invention provides a thick aluminum etching method, referring to fig. 1, the method includes the following steps:
s100: a metal interconnection structure is formed on the wafer and comprises a first buffer layer, a thick aluminum layer and a second buffer layer which are sequentially arranged on the wafer, and a photoresist layer is formed on the second buffer layer.
S200: and patterning the photoresist layer, and etching the second buffer layer according to the pattern of the photoresist layer.
S300: and etching the thick aluminum layer with the first proportional thickness by using nitrogen, chlorine and boron trichloride.
S400: keeping the pressure of the cavity unchanged, reducing the gas flow of nitrogen and boron trichloride, and etching the remaining thick aluminum layer with the thickness of the second proportion and the first buffer layer, wherein the second proportion is smaller than the first proportion.
Referring to fig. 2A, a front-end process of a semiconductor device is first completed on a wafer 100 to form a circuit structure of a chip. Metal interconnect structures are then formed on the wafer 100. The metal interconnection structure includes a first buffer layer 110, a thick aluminum layer 120, and a second buffer layer 130 sequentially disposed on the wafer 100. A photoresist layer 140 is also formed on the second buffer layer 130 for the patterning process.
Specifically, in this embodiment, after the circuit structure of the chip is formed on the wafer 100, the first buffer layer 110, the thick aluminum layer 120, and the second buffer layer 130 may be formed on the wafer 100 by sputtering, and the photoresist layer 140 may be coated on the second buffer layer 130. Then, the photoresist layer 140 is patterned, and the photoresist layer 140 is used as a mask to etch each film layer to form the connection lines. In this embodiment, the thickness of the thick aluminum layer 120 may be 0.46um to 3 um.
In one embodiment, with continued reference to fig. 2A, in order to protect the pattern of the photoresist layer 140 and prevent the reflected light from affecting the pattern size of the photoresist layer 140, an anti-reflection layer 150 may be further deposited on the second buffer layer 130, and a photoresist layer may be deposited on the anti-reflection layer 150. The anti-reflection layer 150 may absorb light reflected during photolithography to prevent a deviation in the pattern size of the photoresist layer 140. In this embodiment, the anti-reflective layer 150 may be a dielectric anti-reflective layer. The material of the dielectric antireflective layer may be silicon nitride or other nitrogen-containing compounds. Of course, the material of the dielectric antireflection layer may also be a nitrogen-free dielectric material, and the user may select the material according to the requirement.
Referring to fig. 2B, after forming the layers of the metal interconnect structure, the photoresist layer 140 is patterned to perform an etching step. In this embodiment, the photoresist of the photoresist layer 140 may be a positive photoresist or a negative photoresist. The photoresist layer 140 is exposed and developed, so that the pattern on the reticle can be transferred to the photoresist layer 140.
The anti-reflection layer 150 and the second buffer layer 130 are then sequentially etched according to the pattern of the photoresist layer 140. Wherein, when the anti-reflection layer 150 is etched, the pressure of the cavity can be set to 12 mTorr-20 mTorr. If the chamber pressure is less than 12mTorr, the lower the chamber pressure, the greater the etch rate of the photoresist layer 140, and thus, when the chamber pressure is less than 12mTorr, the faster etch rate of the photoresist layer 140 will decrease the etch selectivity. Therefore, in this embodiment, the cavity pressure can be set to 122mTorr to 20mTorr, the higher the cavity pressure is, the smaller the etching rate of the photoresist layer 140 is, and the faster the reaction rate of the etching gas to the anti-reflection layer 150 is, so as to achieve the etching selectivity meeting the requirement. The etching gas is chlorine (Cl) 2 ) And trifluoromethane (CHF) 3 ) And Cl 2 And CHF 3 The gas flow ratio of (A) is 6: 1-6.5: 1.
Next, the second buffer layer 130 is etched while maintaining the chamber pressure of the reaction chamber. In this embodiment, the second buffer layer 130 may be a titanium layer or a titanium nitride layer. In order to enhance the adhesion of the thick aluminum layer 120 to the upper layer structure, the second buffer layer 130 may also include a metal titanium layer disposed on the thick aluminum layer 120, and a titanium nitride layer disposed on the metal titanium layer, wherein gold is usedThe titanium layer may increase adhesion between the aluminum layer 120 and the titanium nitride layer. Correspondingly, the first buffer layer 110 may be a titanium layer or a titanium nitride layer, and of course, the first buffer layer 110 may also include a titanium layer and a titanium nitride layer, wherein the titanium nitride layer is disposed on the wafer, and the titanium layer is disposed between the titanium nitride layer and the thick aluminum layer 120 to increase the adhesion between the thick aluminum layer 120 and the titanium nitride layer. In this embodiment, the first buffer layer 110 and the second buffer layer 130 both include a titanium metal layer and a titanium nitride layer. When the second buffer layer 130 includes a titanium metal layer and a titanium nitride layer, chlorine gas and boron trichloride (BCl) are introduced into the reaction chamber 3 ) And Cl 2 And BCl 3 The gas flow ratio of the titanium nitride layer to the reaction chamber is 0.9: 1-1: 1, the etching time and the power of the reaction chamber are controlled according to the thicknesses of the titanium nitride layer and the titanium nitride layer, and the titanium nitride layer are etched in sequence.
After the second buffer layer 130 is etched, the thick aluminum layer 120 is subjected to main etching. Firstly, stabilize the cavity pressure, keep the cavity pressure unchanged, and use nitrogen (N) 2 ) The etching gas consisting of chlorine and boron trichloride performs a main etch to etch a major portion of the thick aluminum layer 120. Wherein N is 2 Flow rate of (2) sccm, Cl 2 And BCl 3 The gas flow ratio of (1: 1), specifically, Cl 2 And BCl 3 The gas flow rate of the gas source can be 85sccm to 120 sccm. In the etching process, because the reaction gas and the aluminum can emit light, whether the etching position is close to the end point or not is judged by detecting the luminous intensity. When the light emission intensity becomes weak and reaches a predetermined value, it can be determined that the etching position is close to the end point of the thick aluminum layer 120, i.e., the thick aluminum layer 120 of the first specific thickness is etched away. Since the remaining thick aluminum layer 120 is thinner, N is reduced near the end point 2 And BCl 3 Of gas flow of (2) so that N 2 The gas flow rate of (1) is 7sccm to 9sccm, BCl 3 The gas flow rate of (a) is 70sccm to 90sccm and the remaining thick aluminum layer 120 of the second proportional thickness is etched. Wherein, the second proportional thickness is smaller than the first proportional thickness, the first proportional thickness can be 90% -95% of the thick aluminum layer, and the second proportional thickness can be 5% -10% of the thick aluminum layer. In this embodiment, etchingThe time taken for the second proportional thickness thick aluminum layer 120 is less than the time taken to etch the first proportional thickness thick aluminum layer. The etching time can be controlled by controlling the flow of etching gas, the pressure of the cavity, the power of the cavity and the like.
After etching the remaining thick aluminum layer 120 with the second proportional thickness, the first buffer layer 110 is etched using the same reaction conditions (cavity pressure, etching gas and its proportion, chamber power).
Referring to fig. 2C, since the surface of the wafer 100 is covered with the insulating layer, the insulating layer on the surface of the wafer 100 needs to be etched. Due to Cl 2 And BCl 3 Different from the reaction rate of the insulating layer, so that Cl in the previous step is exchanged 2 And BCl 3 Gas flow rate ratio of (i.e. BCl) 3 ：Cl 2 The gas flow ratio of (1.2): 1, by increasing BCl 3 The etching rate of the insulating layer is improved.
In the method provided by the embodiment, during the etching process of each film layer, the etching rate of the reaction gas to the photoresist is reduced by comprehensively controlling parameters such as the pressure of the cavity, the type and the flow of the reaction gas, and the like, so that the selection ratio of the thick aluminum layer 120 to the photoresist layer 140 is finally 3-3.5. Compared with the traditional technology in which an etching barrier layer is added, the etching selection ratio of the thick aluminum layer to the photoresist layer 140 is adjusted by adjusting the process parameters in the etching process, so that damage to the thick aluminum layer caused by insufficient blocking of the photoresist is prevented, the process flow is simplified, and the product quality is improved.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A thick aluminum etching method is characterized by comprising the following steps:
forming a metal interconnection structure on a wafer, wherein the metal interconnection structure comprises a first buffer layer, a thick aluminum layer and a second buffer layer which are sequentially arranged on the wafer, and a photoresist layer is formed on the second buffer layer;
patterning the photoresist layer, and etching the second buffer layer according to the pattern of the photoresist layer;
etching the thick aluminum layer with a first proportional thickness by using nitrogen, chlorine and boron trichloride;
keeping the pressure of the cavity in the step of etching the thick aluminum layer with the first proportional thickness unchanged, reducing the flow of the nitrogen and the boron trichloride, and etching the thick aluminum layer with the remaining second proportional thickness and the first buffer layer, wherein the second proportional thickness is smaller than the first proportional thickness.
2. The thick aluminum etching method according to claim 1, further comprising a step of forming an anti-reflection layer on the second buffer layer, the photoresist layer being formed on the anti-reflection layer;
the patterning the photoresist layer and etching the second buffer layer according to the pattern of the photoresist layer include:
and patterning the photoresist layer, and sequentially etching the anti-reflection layer and the second buffer layer according to the pattern of the photoresist layer.
3. The thick aluminum etching method according to claim 2, wherein etching gases for etching the anti-reflection layer are chlorine and trifluoromethane, and the flow ratio of the chlorine to the trifluoromethane is 6: 1-6.5: 1;
the etching gas for etching the second buffer layer is chlorine and boron trichloride, and the flow ratio of the chlorine to the boron trichloride is 0.9: 1-1: 1.
4. The thick aluminum etching method as claimed in claim 1, wherein when the thick aluminum layer with the first proportional thickness is etched, the cavity pressure of the reaction chamber is 12mTorr to 20mTorr, the nitrogen flow rate is 12sccm, and the flow ratio of the chlorine gas to the boron trichloride is 1:1.
5. The thick aluminum etching method of claim 4, wherein the flow rates of the chlorine gas and the boron trichloride are both 85sccm to 90 sccm.
6. The method of claim 5, wherein reducing the flow of nitrogen and boron trichloride to etch the remaining second proportional thickness of the thick aluminum layer and the first buffer layer comprises:
and reducing the flow of the nitrogen and the boron trichloride until the gas flow of the nitrogen is 7 sccm-9 sccm, the gas flow of the boron trichloride is 70 sccm-90 sccm, and etching the thick aluminum layer with the rest second proportional thickness and the first buffer layer.
7. The thick aluminum etching method of claim 6, wherein the first proportional thickness is 90% to 95% of the thick aluminum layer and the second proportional thickness is 5% to 10% of the thick aluminum layer.
8. The thick aluminum etching method of claim 7, wherein the wafer further comprises an insulating layer;
reducing the nitrogen gas with the flow of boron trichloride, the thick aluminium layer that the remaining second proportion thickness of sculpture still includes after the first buffer layer:
exchanging the flow ratio of the chlorine gas to the boron trichloride, wherein the flow ratio of the chlorine gas to the boron trichloride is 1:1.2, reducing the flow of the nitrogen gas, and etching the insulating layer.
9. The thick aluminum etching method of claim 1, wherein the first buffer layer and the second buffer layer comprise a metal titanium layer and/or a titanium nitride layer; when the first buffer layer comprises the metal titanium layer and the titanium nitride layer, the metal titanium layer is arranged on the titanium nitride layer, and the thick aluminum layer is arranged on the metal titanium layer;
when the second buffer layer comprises the metal titanium layer and the titanium nitride layer, the metal titanium layer is arranged on the thick aluminum layer, and the titanium nitride layer is arranged on the metal titanium layer.
10. The thick aluminum etching method of claim 1, wherein the thickness of the thick aluminum layer is greater than or equal to 0.46um to 3 um.
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Publication number Priority date Publication date Assignee Title
CN103325678A (en) * 2013-05-20 2013-09-25 扬州晶新微电子有限公司 IC two- micrometer-thick aluminum etching process method
CN103730412A (en) * 2014-01-07 2014-04-16 上海华虹宏力半导体制造有限公司 Metal interconnecting wire formation method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103325678A (en) * 2013-05-20 2013-09-25 扬州晶新微电子有限公司 IC two- micrometer-thick aluminum etching process method
CN103730412A (en) * 2014-01-07 2014-04-16 上海华虹宏力半导体制造有限公司 Metal interconnecting wire formation method

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