CN112003582A - Forming process of surface acoustic wave filter - Google Patents
Forming process of surface acoustic wave filter Download PDFInfo
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- CN112003582A CN112003582A CN202010754883.0A CN202010754883A CN112003582A CN 112003582 A CN112003582 A CN 112003582A CN 202010754883 A CN202010754883 A CN 202010754883A CN 112003582 A CN112003582 A CN 112003582A
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- photoresist
- metal film
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- forming
- acoustic wave
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- 238000000034 method Methods 0.000 title claims abstract description 39
- 230000008569 process Effects 0.000 title claims abstract description 37
- 238000010897 surface acoustic wave method Methods 0.000 title claims abstract description 15
- 229920002120 photoresistant polymer Polymers 0.000 claims abstract description 50
- 239000002184 metal Substances 0.000 claims abstract description 28
- 238000005530 etching Methods 0.000 claims abstract description 23
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 17
- 239000001301 oxygen Substances 0.000 claims abstract description 17
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 17
- TXEYQDLBPFQVAA-UHFFFAOYSA-N tetrafluoromethane Chemical compound FC(F)(F)F TXEYQDLBPFQVAA-UHFFFAOYSA-N 0.000 claims abstract description 14
- 238000001312 dry etching Methods 0.000 claims abstract description 7
- 239000003292 glue Substances 0.000 claims abstract description 7
- 239000004065 semiconductor Substances 0.000 claims abstract description 6
- 238000000151 deposition Methods 0.000 claims abstract description 5
- 239000000758 substrate Substances 0.000 claims abstract description 5
- 238000010926 purge Methods 0.000 claims abstract description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 18
- 238000010438 heat treatment Methods 0.000 claims description 16
- 125000004430 oxygen atom Chemical group O* 0.000 claims description 16
- 230000005684 electric field Effects 0.000 claims description 10
- 229910052757 nitrogen Inorganic materials 0.000 claims description 9
- 230000000704 physical effect Effects 0.000 claims description 4
- 238000013461 design Methods 0.000 abstract description 7
- 238000000465 moulding Methods 0.000 abstract description 5
- 238000006243 chemical reaction Methods 0.000 description 6
- 238000011161 development Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000009471 action Effects 0.000 description 2
- 238000010295 mobile communication Methods 0.000 description 2
- 239000004480 active ingredient Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005243 fluidization Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/25—Constructional features of resonators using surface acoustic waves
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
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- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Micromachines (AREA)
- Photosensitive Polymer And Photoresist Processing (AREA)
Abstract
The invention discloses a forming process of a surface acoustic wave filter, which comprises the following steps: s1, depositing a metal film layer on the upper surface of the semiconductor substrate; s2, forming photoresist on the upper surface of the metal film layer and carrying out pre-baking treatment; s3, exposing the photoresist by using a mask; s4, developing the photoresist to form a photoresist pattern the same as the device image; s5, carrying out postbaking treatment on the product; s6, carrying out micro-etching on the gummosis at the bottom of the side wall of the photoresist pattern in a plasma environment by using oxygen and tetrafluoromethane; s7, forming a metal film pattern which is the same as the photoresist pattern after etching the metal film layer by using a dry etching process; s8, removing the photoresist on the upper surface of the metal film to obtain a filter device; and S9, purging the surface of the filter device by using an ion blower. The molding process can carry out micro-etching on the flowing glue, thereby producing the surface acoustic wave filter with lines meeting the requirements of a design layout.
Description
Technical Field
The invention relates to a forming process of a surface acoustic wave filter, belonging to a forming process of a semiconductor device.
Background
A surface acoustic wave filter (SAWF, hereinafter referred to as acoustic surface) is widely applied to radio frequency mobile communication, and along with the development of communication technology, the frequency band to which the saw filter is applied is increasing. A mobile phone at least needs to support requirements of 2G, 3G, 4G, 5G, WiFi, GPS, and the like, so that a sound table with different frequencies is needed to meet different requirements, high frequency is a trend requirement for development of mobile communication sound table devices, but the higher the frequency is, the thinner the line width (hereinafter referred to as line width) of the internal structure of the sound table is, and the requirement for the production process is higher and higher. Under the existing technical conditions, especially for manufacturing submicron or even deep submicron line width acoustic surface devices, photoresist is deformed at a certain temperature to generate fluidization to form gummosis, so that part of a metal film layer after exposure and development is covered by the gummosis, and under the dry etching action, the part which needs to be etched originally is not effectively removed due to the covering of the gummosis, and finally, the burr on the edge of the etched line is far away from the line width required by design, so that the performance of the product is further influenced, how to ensure that the line width meets the design requirement is further ensured, and further ensuring that the electrical performance of the device becomes an important process consideration.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the forming process of the surface acoustic wave filter can be used for micro-etching the flowing glue, so that the surface acoustic wave filter with lines meeting the design layout requirement is produced.
In order to solve the technical problems, the technical scheme of the invention is as follows: a molding process of a surface acoustic wave filter comprises the following steps:
s1, depositing a metal film layer on the upper surface of the semiconductor substrate;
s2, forming a layer of photoresist on the upper surface of the metal film layer and carrying out pre-baking treatment;
s3, exposing the photoresist by using a mask;
s4, developing the photoresist by utilizing a developing process to form a photoresist pattern which is the same as the device image;
s5, carrying out postbaking treatment on the product;
s6, carrying out micro-etching on the gummosis at the bottom of the side wall of the photoresist pattern in a plasma environment by using oxygen and tetrafluoromethane;
s7, forming a metal film pattern which is the same as the photoresist pattern after etching the metal film layer by using a dry etching process;
s8, removing the photoresist on the upper surface of the metal film to obtain a filter device;
and S9, purging the surface of the filter device by using an ion blower.
As a preferable scheme, the specific process flow of step S6 is as follows:
s61, introducing oxygen and tetrafluoromethane into a vacuum chamber with 100Pa according to the flow ratio of 50: 1;
s62, ionizing oxygen into oxygen atoms by using a 13.56Mhz radio frequency power supply;
s63, applying a radio frequency electric field of 200W to the vacuum cavity, enabling oxygen atoms to move in the direction vertical to the metal film layer under the physical action of the radio frequency electric field, and enabling the oxygen atoms to react with the flowing glue at the bottom of the side wall of the photoresist pattern to carry out micro-etching, wherein the micro-etching time is 31-35 seconds;
and S64, introducing nitrogen of 50SCCM to clean the vacuum cavity after the photoresist is removed, and continuously vacuumizing to ensure that the vacuum degree in the cavity is 100 Pa.
Preferably, the oxygen flow rate in step S61 is 1000SCCM, and the corresponding tetrafluoromethane is 20 SCCM.
Preferably, a step of post-exposure baking S3-4 is added between step S3 and step S4 of the molding process, the step S3-4 is to place the exposed product above a hot plate for non-contact heating, the heating temperature is 105 ℃, a gap of 5-10 microns is arranged between the bottom of the product and the hot plate, the heating time is 90S, and nitrogen protection is filled during heating.
After the technical scheme is adopted, the invention has the effects that: the forming process is added with the step S6 on the basis of the original forming process, and the flowing glue at the bottom of the side wall of the photoresist pattern is subjected to micro etching by utilizing oxygen and tetrafluoromethane under the plasma environment; therefore, the lines of the photoresist pattern are clear, the metal strip width manufacturing process in the submicron lines is improved, and the breakthrough of the acoustic surface device to higher frequency (thinner line width) is realized.
The specific process flow of the step S6 is as follows:
s61, introducing oxygen and tetrafluoromethane into a vacuum chamber with 100Pa according to the flow ratio of 50: 1;
s62, ionizing oxygen into oxygen atoms by using a 13.56Mhz radio frequency power supply;
s63, applying a radio frequency electric field of 200W to the vacuum cavity, enabling oxygen atoms to move in the direction vertical to the metal film layer under the physical action of the radio frequency electric field, and enabling the oxygen atoms to react with the flowing glue at the bottom of the side wall of the photoresist pattern to carry out micro-etching, wherein the micro-etching time is 31-35 seconds;
s64, after photoresist is removed, 50SCCM nitrogen is introduced to clean the vacuum cavity, and vacuum is continuously pumped to ensure that the vacuum degree in the cavity is 100Pa, therefore, the micro-etching process utilizes tetrafluoromethane as a catalyst, and utilizes ionized oxygen atoms as an etching medium, the oxygen atoms vertically move under the action of a radio frequency electric field to contact with the flowing photoresist and generate micro-etching reaction, and simultaneously controls the intensity of the radio frequency electric field to enable the oxygen atoms to react with the flowing photoresist and simultaneously reduce the reaction of the oxygen atoms with other photoresists except the flowing photoresist, so that the clearness and regularity of photoresist lines are further ensured, and the lines of the photoresist directly influence the clearness and regularity of metal lines after dry etching, and the line precision of the surface acoustic wave filter is higher, and thinner lines can be manufactured to meet the use condition of higher frequency.
And because the step of post-exposure baking S3-4 is added between the step S3 and the step S4 of the molding process, the step S3-4 places the exposed product above a hot plate for non-contact heating, the heating temperature is 105 ℃, a gap of 5-10 microns is arranged between the bottom of the product and the hot plate, the heating time is 90S, and nitrogen protection is filled during heating, the purpose is to reduce the influence of standing wave effect and enable the chemical reaction to be more sufficient. During exposure, standing wave effect will occur at the boundary between the exposed area and the non-exposed area, and the standing wave effect will form transition areas with different intensity near the boundary between the two areas, which will affect the size and resolution of the pattern formed after development. Meanwhile, the chemical reaction of the exposed light is not completely finished, the reaction is completely finished through the post-baking operation, and simultaneously, the active ingredients generated through the light reaction are diffused in the process, so that the latent image generated by light intensity distribution is enhanced through a chemical method, and the pattern appearance is more accurately controlled.
Drawings
The invention is further illustrated with reference to the following figures and examples.
FIG. 1 is a process flow diagram of an embodiment of the invention;
FIG. 2 is a bar width aspect of a filter taken under a scanning electron microscope;
Detailed Description
The present invention is described in further detail below with reference to specific examples.
As shown in fig. 1, a process for forming a surface acoustic wave filter includes the steps of:
s1, depositing a metal film layer on the upper surface of the semiconductor substrate, wherein the metal film layer is formed on the semiconductor substrate by adopting a deposition mode;
s2, forming a layer of photoresist on the upper surface of the metal film layer and carrying out pre-baking treatment;
s3, exposing the photoresist by using a mask;
s4, developing the photoresist by utilizing a developing process to form a photoresist pattern which is the same as the device image;
s5, carrying out postbaking treatment on the product; the photoresist can fluidize after post-baking, so that the photoresist can flow to the bottom of a photoresist graph to form flowing photoresist, and the conventional process can cause serious lateral corrosion due to the flowing photoresist when dry etching is carried out, the etched lines are aggravated in deformation and generally are inverted trapezoidal lines, so that the performance of a device is also changed, the difference between theoretical design and actual manufacture is large, and the process can not realize the design requirement.
S6, carrying out micro-etching on the gummosis at the bottom of the side wall of the photoresist pattern in a plasma environment by using oxygen and tetrafluoromethane;
the specific process flow of step S6 is as follows:
s61, introducing oxygen and tetrafluoromethane into a vacuum chamber with 100Pa according to the flow ratio of 50: 1; it is generally preferred that the flow rate of oxygen be 1000SCCM and the flow rate of tetrafluoromethane be 20 SCCM.
S62, ionizing oxygen into oxygen atoms by using a 13.56Mhz radio frequency power supply;
s63, applying a radio frequency electric field of 200W to the vacuum cavity, enabling oxygen atoms to move in the direction vertical to the metal film layer under the physical action of the radio frequency electric field, enabling the oxygen atoms to react with the flowing glue at the bottom of the side wall of the photoresist pattern to carry out micro-etching, wherein the micro-etching time is 31-35 seconds, and the preferable micro-etching time is 33 seconds;
s64, introducing 50SCCM nitrogen to clean the vacuum cavity after the photoresist is removed, continuously vacuumizing to ensure that the vacuum degree in the cavity is 100Pa, replacing oxygen and tetrafluoromethane in the vacuum cavity by using the nitrogen, and then keeping the vacuum degree to a certain degree, thereby facilitating subsequent treatment.
S7, forming a metal film pattern which is the same as the photoresist pattern after etching the metal film layer by using a dry etching process;
s8, removing the photoresist on the upper surface of the metal film to obtain a filter device;
and S9, purging the surface of the filter device by using an ion blower.
And adding a step of post-exposure baking S3-4 between the step S3 and the step S4 of the molding process, wherein the step S3-4 is to place the exposed product above a hot plate for non-contact heating, the heating temperature is 105 ℃, a gap of 5-10 microns, preferably a gap of 5 microns, is arranged between the bottom of the product and the hot plate, the heating time is 90S, and nitrogen protection is filled during heating.
As shown in fig. 2, fig. 2 is a width of a filter device produced by the process, which is photographed under a scanning electron microscope, and it can be found from the figure that the uniformity of the width of the filter device is relatively consistent, and the shape of the filter device completely meets the design requirements.
The above-mentioned embodiments are merely descriptions of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and various modifications and alterations made to the technical solution of the present invention without departing from the spirit of the present invention are intended to fall within the scope of the present invention defined by the claims.
Claims (4)
1. A forming process of a surface acoustic wave filter is characterized in that: the method comprises the following steps:
s1, depositing a metal film layer on the upper surface of the semiconductor substrate;
s2, forming a layer of photoresist on the upper surface of the metal film layer and carrying out pre-baking treatment;
s3, exposing the photoresist by using a mask;
s4, developing the photoresist by utilizing a developing process to form a photoresist pattern which is the same as the device image;
s5, carrying out postbaking treatment on the product;
s6, carrying out micro-etching on the gummosis at the bottom of the side wall of the photoresist pattern in a plasma environment by using oxygen and tetrafluoromethane;
s7, forming a metal film pattern which is the same as the photoresist pattern after etching the metal film layer by using a dry etching process;
s8, removing the photoresist on the upper surface of the metal film to obtain a filter device;
and S9, purging the surface of the filter device by using an ion blower.
2. A process for forming a surface acoustic wave filter as set forth in claim 1, wherein: the specific process flow of the step S6 is as follows:
s61, introducing oxygen and tetrafluoromethane into a vacuum chamber with 100Pa according to the flow ratio of 50: 1;
s62, ionizing oxygen into oxygen atoms by using a 13.56Mhz radio frequency power supply;
s63, applying a radio frequency electric field of 200W to the vacuum cavity, enabling oxygen atoms to move in the direction vertical to the metal film layer under the physical action of the radio frequency electric field, and enabling the oxygen atoms to react with the flowing glue at the bottom of the side wall of the photoresist pattern to carry out micro-etching, wherein the micro-etching time is 31-35 seconds;
and S64, introducing nitrogen of 50SCCM to clean the vacuum cavity after the photoresist is removed, and continuously vacuumizing to ensure that the vacuum degree in the cavity is 100 Pa.
3. A process for forming a surface acoustic wave filter as set forth in claim 2, wherein: the oxygen flow rate in step S61 was 1000SCCM, and the corresponding tetrafluoromethane was 20 SCCM.
4. A process for forming a surface acoustic wave filter as set forth in claim 3, wherein: and adding a post-exposure baking step S3-4 between the step S3 and the step S4 of the forming process, wherein the step S3-4 is to place the exposed product above a hot plate for non-contact heating, the heating temperature is 105 ℃, a gap of 5-10 microns is arranged between the bottom of the product and the hot plate, the heating time is 90S, and nitrogen protection is filled during heating.
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| CN202010754883.0A CN112003582B (en) | 2020-07-31 | 2020-07-31 | Forming process of surface acoustic wave filter |
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| CN202010754883.0A CN112003582B (en) | 2020-07-31 | 2020-07-31 | Forming process of surface acoustic wave filter |
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| CN112003582B CN112003582B (en) | 2024-06-11 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1174750A (en) * | 1997-08-29 | 1999-03-16 | Kyocera Corp | Surface acoustic wave device and its manufacture |
| JP3417502B2 (en) * | 1995-03-24 | 2003-06-16 | ティーディーケイ株式会社 | Manufacturing method of surface acoustic wave device |
| CN102694518A (en) * | 2012-05-24 | 2012-09-26 | 台州欧文电子科技有限公司 | Manufacturing method for acoustic surface wave element |
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2020
- 2020-07-31 CN CN202010754883.0A patent/CN112003582B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3417502B2 (en) * | 1995-03-24 | 2003-06-16 | ティーディーケイ株式会社 | Manufacturing method of surface acoustic wave device |
| JPH1174750A (en) * | 1997-08-29 | 1999-03-16 | Kyocera Corp | Surface acoustic wave device and its manufacture |
| CN102694518A (en) * | 2012-05-24 | 2012-09-26 | 台州欧文电子科技有限公司 | Manufacturing method for acoustic surface wave element |
Non-Patent Citations (1)
| Title |
|---|
| 维克多·索菲尔（VICTOR A. SOIFER） 等: "衍射光学元件的计算机设计方法", 上海科学技术出版社, pages: 213 - 224 * |
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| CN112003582B (en) | 2024-06-11 |
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