CN117680420A - Wafer cleaning method based on liquid drop impact - Google Patents
Wafer cleaning method based on liquid drop impact Download PDFInfo
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- CN117680420A CN117680420A CN202311856109.0A CN202311856109A CN117680420A CN 117680420 A CN117680420 A CN 117680420A CN 202311856109 A CN202311856109 A CN 202311856109A CN 117680420 A CN117680420 A CN 117680420A
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- Prior art keywords
- liquid
- wafer
- cleaning
- impact
- liquid film
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- 239000007788 liquid Substances 0.000 title claims abstract description 108
- 238000004140 cleaning Methods 0.000 title claims abstract description 59
- 238000000034 method Methods 0.000 title claims abstract description 27
- 239000003344 environmental pollutant Substances 0.000 claims abstract description 23
- 231100000719 pollutant Toxicity 0.000 claims abstract description 23
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 6
- 238000005507 spraying Methods 0.000 claims abstract description 6
- 239000007921 spray Substances 0.000 claims description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 239000008367 deionised water Substances 0.000 claims description 5
- 229910021641 deionized water Inorganic materials 0.000 claims description 5
- 239000000919 ceramic Substances 0.000 claims description 2
- 230000003247 decreasing effect Effects 0.000 claims description 2
- 239000011261 inert gas Substances 0.000 claims description 2
- 238000007664 blowing Methods 0.000 claims 1
- 238000001035 drying Methods 0.000 claims 1
- 235000012431 wafers Nutrition 0.000 abstract description 47
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000005108 dry cleaning Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Landscapes
- Cleaning Or Drying Semiconductors (AREA)
Abstract
The invention provides a wafer cleaning method based on liquid drop impact, which comprises the following steps: in the wafer rotating process, spraying a first cleaning solution to the surface of the wafer to form a continuous liquid film, so that pollutants are desorbed from the surface of the wafer into the liquid film; and continuously dripping liquid drops formed by the second cleaning liquid on the surface of the wafer, lifting up pollutants in the liquid film by continuous impact of the liquid drops, and separating from the wafer along with the flow of the liquid film, wherein the diameter of the liquid drops is 14-30 microns. In the invention, during cleaning, liquid drops with the diameter of 14-30 microns formed by the second cleaning liquid are continuously dropped on the surface of the wafer, and pollutants in the liquid film, especially small-diameter pollutants positioned at the bottom layer of the liquid film, are lifted up by the impact of the liquid drops, so that the pollutants are separated from the wafer along with the flow of the liquid film, the damage to micro patterns on the surface of the wafer caused by the mode of spraying a large amount of high-pressure nitrogen to the cleaning liquid in the prior art is avoided, and the cleaning liquid is suitable for cleaning applications of wafers with the diameter of 14nm and below.
Description
Technical Field
The invention belongs to the technical field of semiconductor cleaning, and particularly relates to a wafer cleaning method based on liquid drop impact.
Background
If the wafer is polluted by dust particles and metal in the manufacturing process, the functions of the internal circuits of the chip are easily damaged, short circuit or open circuit is formed, and the integrated circuit is invalid, so that wet cleaning or dry cleaning work is required except that external pollution sources such as high-temperature diffusion, ion implantation and the like are eliminated.
Wet cleaning is a process in which impurities adsorbed on the surface of an object to be cleaned are desorbed (desorbed) from the surface of the object to be cleaned by chemical reaction or dissolution of various chemical reagents with impurities and oil stains, and then rinsed, thereby obtaining a clean surface.
During flushing, the cleaning liquid is atomized and sprayed out by high-pressure and high-flow nitrogen to flush the surface of the wafer, so that the method has good cleaning effect and slight wafer damage, and can meet the cleaning requirement of the wafer with the diameter of more than 28 nm. However, the pattern structure on the surface of a wafer of 14nm or less is more complicated and fragile, and the pattern structure is easily damaged by the conventional method.
Disclosure of Invention
In view of the above, a method for cleaning a wafer based on droplet impact is provided.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention provides a wafer cleaning method based on liquid drop impact, which comprises the following steps:
in the wafer rotating process, spraying a first cleaning solution to the surface of the wafer to form a continuous liquid film, so that pollutants are desorbed from the surface of the wafer into the liquid film;
and continuously dripping liquid drops formed by the second cleaning liquid on the surface of the wafer, lifting up pollutants in the liquid film by continuous impact of the liquid drops, and separating from the wafer along with the flow of the liquid film, wherein the diameter of the liquid drops is 14-30 microns.
In the invention, during cleaning, liquid drops with the diameter of 14-30 microns formed by the second cleaning liquid are continuously dropped on the surface of the wafer, and pollutants in the liquid film, especially small-diameter pollutants positioned at the bottom layer of the liquid film, are lifted up by the impact of the liquid drops, so that the pollutants are separated from the wafer along with the flow of the liquid film, the damage to micro patterns on the surface of the wafer caused by the mode of spraying a large amount of high-pressure nitrogen to the cleaning liquid in the prior art is avoided, and the cleaning liquid is suitable for cleaning applications of wafers with the diameter of 14nm and below.
Drawings
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a schematic diagram of a spray head according to the present invention;
fig. 3 is a schematic diagram of a spray head of the present invention.
Detailed Description
Embodiments of the present invention will be described below with reference to the drawings. The embodiments described in the present specification are not intended to be exhaustive or to represent the only embodiments of the present invention. The following examples are presented for clarity of illustration of the invention of the present patent and are not intended to limit the embodiments thereof. It will be apparent to those skilled in the art that various changes and modifications can be made in the embodiment described, and that all the obvious changes or modifications which come within the spirit and scope of the invention are deemed to be within the scope of the invention.
As shown in fig. 1, the embodiment of the application provides a wafer cleaning method based on droplet impact, which is used for cleaning wafers with the diameter of 14nm and below, and the pattern structure of the surface of the wafer with the diameter of 14nm and below becomes more complex, is weaker, has larger pattern density and smaller size, provides higher challenges for the cleaning process, protects the patterns from being damaged, and is the most basic requirement of the cleaning process. The specific flow of the method in the embodiment of the application is as follows:
s101, in the wafer rotation process, spraying a first cleaning solution to the surface of the wafer to form a continuous liquid film, so that pollutants in the liquid film are desorbed from the surface of the wafer into the liquid film.
S102, continuously dripping liquid drops formed by the second cleaning liquid on the surface of the wafer, lifting up pollutants in the liquid film through continuous impact of the liquid drops, and separating from the wafer along with flow of the liquid film.
It should be noted that, in the wafer rotation process, the flow velocity of the top layer of the liquid film is the largest, the flow velocity is smaller as the top layer is far away, the bottom layer of the liquid film can be regarded as static, on the basis, the large-diameter pollutant can be separated from the wafer along with the flow of the liquid film due to the larger volume of the pollutant, and the pollutant with small diameter, especially the pollutant with small diameter, which is positioned at the bottom layer of the liquid film and is close to static, is difficult to separate from the wafer. Therefore, in the embodiment of the application, the liquid drops continuously drop into the liquid film to impact the liquid film, so that pollutants in the liquid film, especially the pollutants with small diameter at the bottom layer of the liquid film, are raised, and are separated from the wafer along with the flow of the liquid film, and the liquid drops drop into the liquid film to not impact the micro-image on the surface of the wafer and damage the micro-image on the surface of the wafer.
Wherein the diameter of the liquid drop is 14-30 micrometers, and the second cleaning liquid is extruded by continuous vibration force to form uniform and controllable liquid drops through the liquid drop holes on the spray head.
Specifically, as shown in fig. 2 and 3, the spray head includes a spray head body 110, a flow channel 111 is provided in the spray head body 110, and the spray head body 110 is provided with a liquid inlet 112, a liquid outlet 113, a mounting cavity 114 and a plurality of liquid dropping holes 115 located on the lower end surface thereof.
The flow channel 111 is a flat sandwich.
Illustratively, the flow channel 111 may have a U-shaped vertical cross section with a horizontal section 111a passing horizontally from the inside of the lower end of the nozzle body 110, and is communicated with the plurality of drip holes 115 by the horizontal section 111a, see FIG. 3.
As shown in fig. 2, the liquid inlet 112 and the liquid outlet 113 are both located on the upper end surface of the nozzle body 110 and are connected to two ends of the flow channel 111.
As shown in fig. 3, the mounting cavity 114 is located at the upper side of the horizontal segment 111a, in which the vibration source 120 is provided, the vibration source 120 is used to apply a continuous vibration force on the upper side of the horizontal segment 111a, the second cleaning liquid 3 flowing through the horizontal segment 111a is pressed by the vibration force, so that the second cleaning liquid 3 forms the liquid droplets 4 through the liquid droplet holes 115, and the mounting cavity 114 may be a blind hole extending downward from the upper surface of the nozzle body 110 to the horizontal segment 111a, which is concentric with the nozzle body 110, and the vibration source 120 may be a piezoelectric ceramic vibration member circumscribing the frequency generator 2 (such as an ultrasonic generator) and converting the electrical signal of the frequency generator 2 into the continuous vibration force.
The drip holes 115 have a diameter of 6-30 μm, which is a tapered hole with a radius gradually decreasing from top to bottom, for the purpose of increasing the flow rate of the liquid, and a plurality of drip holes 115 may be arranged in a circular array.
In order to ensure that the spray head is in a clean environment, when the spray head does not work, the spray head is soaked in a water tank of deionized water; before cleaning, after the spray head is taken out from the water tank, the residual liquid can cover a plurality of liquid drop holes 115 on the lower surface of the spray head due to surface tension, so that liquid drops cannot be independently formed in each liquid drop hole 115 during cleaning, and therefore, the lower surface of the spray head needs to be purged and dried by nitrogen or inert gas, and the residual liquid on the lower surface of the spray head is blown and dried; after the cleaning operation is completed, the spray head is soaked in deionized water in the water tank again.
Wherein, the first cleaning liquid adopts a conventional cleaning liquid such as deionized water or SC1 (a mixture of ammonia water, hydrogen peroxide and water), the second cleaning liquid adopts deionized water or diluted SC1, and the spray head adopts a material compatible with the second cleaning liquid such as quartz or plastics.
From the above, in the embodiment of the application, when the wafer is cleaned, the droplets with the diameter of 14-30 micrometers formed by the second cleaning liquid are continuously dropped onto the surface of the wafer, and the pollutants in the liquid film, especially the pollutants with the small diameter at the bottom layer of the liquid film, are lifted up by the impact of the droplets, so that the pollutants are separated from the wafer along with the flow of the liquid film, the damage to the micropattern on the surface of the wafer caused by the mode of jetting the cleaning liquid by a large amount of high-pressure nitrogen in the prior art is avoided, and the method is suitable for the cleaning application of the wafer with the diameter of 14nm or below.
It will be apparent to those skilled in the art that the above embodiments are provided for illustration only and not for limitation of the invention, and that variations and modifications of the above described embodiments are intended to fall within the scope of the claims of the invention as long as they fall within the true spirit of the invention.
Claims (9)
1. A method of cleaning a wafer based on droplet impact, comprising:
in the wafer rotating process, spraying a first cleaning solution to the surface of the wafer to form a continuous liquid film, so that pollutants are desorbed from the surface of the wafer into the liquid film;
and continuously dripping liquid drops formed by the second cleaning liquid on the surface of the wafer, lifting up pollutants in the liquid film by continuous impact of the liquid drops, and separating from the wafer along with the flow of the liquid film, wherein the diameter of the liquid drops is 14-30 microns.
2. The method of claim 1, wherein the continuously dropping droplets of the second cleaning liquid onto the surface of the wafer further comprises:
and extruding the second cleaning liquid through continuous vibration force to form the liquid drops through the liquid drop holes on the spray head.
3. The wafer cleaning method based on liquid drop impact according to claim 2, wherein the nozzle comprises a nozzle body, a flow channel is arranged in the nozzle body, a liquid inlet, a liquid outlet and a mounting cavity are arranged on the nozzle body, the flow channel is provided with a horizontal section horizontally passing through the inner part of the lower end of the nozzle body, the liquid inlet and the liquid outlet are respectively connected with two ends of the flow channel, the mounting cavity is positioned on the upper side of the horizontal section, a vibration source for applying continuous vibration force above the horizontal section is arranged in the mounting cavity, a plurality of liquid drop holes communicated with the horizontal section are formed on the lower end face of the nozzle body, and the diameter of each liquid drop hole is 6-30 microns.
4. A method of cleaning a wafer based on droplet impact as claimed in claim 3, wherein the droplet orifice is a tapered orifice with a gradually decreasing radius from top to bottom.
5. The wafer cleaning method based on liquid drop impact according to claim 3, wherein the vertical section of the flow channel is U-shaped, and the liquid inlet and the liquid outlet are both positioned on the upper end face of the nozzle body.
6. A method of cleaning a wafer based on droplet impact as claimed in claim 3, wherein the flow channel is a flat sandwich.
7. A method of cleaning a wafer based on droplet impact as claimed in claim 3, wherein the mounting cavity is a blind hole extending downwardly from the upper surface of the showerhead body to the horizontal section, the blind hole being concentric with the showerhead body.
8. A method of cleaning a wafer based on droplet impact as claimed in claim 3, wherein the vibration source is a piezoelectric ceramic vibration member with an external frequency generator.
9. A method of cleaning a wafer based on droplet impact according to any one of claims 3-8, further comprising:
before cleaning, taking out the spray head from the water tank, and blowing and drying nitrogen or inert gas on the lower surface of the spray head;
after the cleaning work is completed, the spray head is soaked in deionized water in the water tank.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311856109.0A CN117680420A (en) | 2023-12-29 | 2023-12-29 | Wafer cleaning method based on liquid drop impact |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311856109.0A CN117680420A (en) | 2023-12-29 | 2023-12-29 | Wafer cleaning method based on liquid drop impact |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117680420A true CN117680420A (en) | 2024-03-12 |
Family
ID=90135335
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311856109.0A Pending CN117680420A (en) | 2023-12-29 | 2023-12-29 | Wafer cleaning method based on liquid drop impact |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117680420A (en) |
-
2023
- 2023-12-29 CN CN202311856109.0A patent/CN117680420A/en active Pending
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