CN215357898U - Coarse polishing equipment for recycled wafers - Google Patents
Coarse polishing equipment for recycled wafers Download PDFInfo
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- CN215357898U CN215357898U CN202121737676.0U CN202121737676U CN215357898U CN 215357898 U CN215357898 U CN 215357898U CN 202121737676 U CN202121737676 U CN 202121737676U CN 215357898 U CN215357898 U CN 215357898U
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Abstract
The utility model discloses a rough polishing device for a recycled wafer, which comprises: the device comprises a polishing machine, a liquid storage container, a silica sol container, a chelating agent container and a PH container, wherein the silica sol container is connected with the liquid storage container through a first metering pump, the chelating agent container is connected with the liquid storage container through a second metering pump, the PH container is connected with the liquid storage container through a third metering pump, and an online PH meter and an online conductivity meter are arranged in the liquid storage container; the online PH meter is in control connection with the third metering pump, and the online conductivity meter is in control connection with the second metering pump; the liquid inlet end of the polishing machine is connected with the liquid storage container through a fourth metering pump, and the liquid storage end of the polishing machine is communicated with the liquid storage container. The technical scheme of the utility model aims to control the concentration of metal ions in the circulating polishing solution and the pH value of the polishing solution, reduce the metal ion pollution on the surface of the silicon wafer and improve the polishing quality and yield of the silicon wafer.
Description
Technical Field
The utility model relates to the technical field of chemical mechanical polishing, in particular to rough polishing equipment for a recycled wafer.
Background
The general polishing step of the recycled wafer can be divided into 3 steps of rough polishing, fine polishing, etc., wherein the rough polishing solution of the rough polishing is recycled for reducing the production cost. However, in the rough polishing process of the recycled wafer, two problems are caused by the recycling of the polishing solution, namely, the problem (1) that the recycled polishing solution may absorb carbon dioxide in the air to cause the pH value of the polishing solution to drift along with the increase of the polishing time so as to influence the polishing rate of the silicon wafer, and the problem (2) that along with the increase of the number of the recycled wafers to be polished, more and more heavy metal ions are generated in the recycled polishing solution and have the opportunity of being deposited on the surface of the silicon wafer and permeating into the silicon wafer in the polishing process so as to seriously influence the quality of the silicon wafer. Therefore, new pH regulators and chelating agents also need to be added into the recycled polishing solution to stabilize the pH and capture the impurity metal ions, especially, as the recycled polishing time of the recycled wafer is prolonged, the water-soluble chelating agents will be gradually consumed by the metal ions, and new water-soluble chelating agent solution needs to be supplemented into the polishing solution in time, which previously needs the production personnel to measure the concentration of the chelating agents in the polishing solution by HPLC or uv absorption spectrophotometer at regular time, which is time-consuming and inconvenient to operate, and cannot be continuously detected and controlled in real time.
SUMMERY OF THE UTILITY MODEL
The utility model mainly aims to provide rough polishing equipment for a recycled wafer, which aims to detect the change of the conductivity and the pH value of a polishing solution in real time, so that the addition of a chelating agent and a pH regulator can be automatically adjusted through a metering pump, the concentration of metal ions in the circulating polishing solution and the pH value of the polishing solution can be controlled in time, the metal ion pollution on the surface of a silicon wafer is greatly reduced, the polishing rate of the polishing solution is stabilized, and the polishing quality and the yield of the silicon wafer are improved.
In order to achieve the above object, the present invention provides a rough polishing apparatus for reclaiming wafers, comprising: the device comprises a polishing machine, a liquid storage container, a silica sol container, a chelating agent container and a PH container, wherein the silica sol container is connected with the liquid storage container through a first metering pump, the chelating agent container is connected with the liquid storage container through a second metering pump, the PH container is connected with the liquid storage container through a third metering pump, and an online PH meter and an online conductivity meter are arranged in the liquid storage container; the online PH meter is in control connection with the third metering pump, and the online conductivity meter is in control connection with the second metering pump; the liquid inlet end of the polishing machine is connected with the liquid storage container through a fourth metering pump, and the liquid storage end of the polishing machine is communicated with the liquid storage container.
Preferably, a filter is connected between the liquid inlet end of the polishing machine and the fourth metering pump.
Preferably, a stirring device is arranged in the liquid storage container.
Preferably, the burnishing machine includes tray, polishing pad, polishing aircraft nose, ceramic dish and drain pipe, the drain pipe with the filter is connected, the play liquid end of tray with stock solution container connects, the polishing pad sets up on the tray, the polishing aircraft nose sets up with liftable the tray top, the ceramic dish sets up the bottom of polishing aircraft nose, the drain pipe sets up polishing aircraft nose's side just is located directly over the tray.
Preferably, the end of the liquid outlet pipe is provided with a spraying head.
Preferably, the polishing pad is made of non-woven fabrics.
Compared with the prior art, the utility model has the beneficial effects that: the online pH meter and the online conductivity meter are installed in the liquid storage container for circulating the polishing solution, so that the polishing solution can be regulated and controlled in long-time circulating operation, the obvious change of the pH value of the polishing solution is prevented, the concentration of the chelating agent is kept, the polishing rate is effectively kept, the surface quality of the polished wafer is improved, the use amount of silica sol is effectively reduced, and the cost of the process for roughly polishing the regenerated wafer is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic view of the structure of the polishing machine of the present invention;
the implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
The rough polishing apparatus for recycling wafers according to the present embodiment, as shown in fig. 1 and fig. 2, includes: the polishing machine 100, a liquid storage container 200, a silica sol container 300, a chelating agent container 400 and a PH container 500, wherein the silica sol container 300 is connected with the liquid storage container 200 through a first metering pump 310, the chelating agent container 400 is connected with the liquid storage container 200 through a second metering pump 410, the PH container 500 is connected with the liquid storage container 200 through a third metering pump 510, and an online PH meter 210 and an online conductivity meter 220 are arranged in the liquid storage container 200; the online pH meter 210 is in control connection with the third metering pump 510, and the online conductivity meter 220 is in control connection with the second metering pump 410; the liquid inlet end of the polishing machine 100 is connected with the liquid storage container 200 through a fourth metering pump 600, and the liquid storage end of the polishing machine 100 is communicated with the liquid storage container 200.
Further, a filter 700 is connected between the liquid inlet end of the polishing machine 100 and the fourth metering pump 600.
Further, a stirring device 230 is disposed in the liquid storage container 200.
Further, the polishing machine 100 includes a tray 110, a polishing pad 120, a polishing head 130, a ceramic disc 140, and a liquid outlet pipe 150, the liquid outlet pipe 150 is connected to the filter 700, a liquid outlet end of the tray 110 is connected to the liquid storage container 200, the polishing pad 120 is disposed on the tray 110, the polishing head 130 is disposed above the tray 110 in a liftable manner, the ceramic disc 140 is disposed at the bottom of the polishing head 130, and the liquid outlet pipe 150 is disposed at a side of the polishing head 130 and directly above the tray 110.
Further, the end of the outlet pipe 150 is provided with a spray head 160.
Further, the polishing pad 120 is made of a non-woven fabric.
The pH and conductivity values of the slurry are precisely measured by an in-line pH meter 210 and an in-line conductivity meter installed inside the reservoir 200. Once the pH and conductivity deviate from the default ranges, the metering pump will begin to operate and will automatically add a quantity of the pH modifier and chelant solution within the pH vessel 500 and chelant vessel 400. The pH of the polishing solution is generally controlled within a range of 10 to 11. the pH can be adjusted by an inorganic base or an organic base, or a combination of both. Generally speaking, the polishing rate of the recycled wafer is increased when the pH value of the polishing solution is increased, but when the pH value reaches a certain degree, the increase of the pH value enters a plateau period for the increase of the polishing rate, the rate cannot be continuously increased, otherwise, the stability of the silica sol liquid is reduced, and meanwhile, the roughness of the polishing effect of the surface of the silicon wafer is also reduced. The conductivity of the polishing solution is controlled to be 2-3mS/cm, and generally, the conductivity is reduced when the chelating agent is consumed, so that the metal pollution on the surface of the regenerated wafer is aggravated, but when the conductivity is too high, the stability of the silica sol is influenced, and the service life of the circulating polishing solution is influenced.
The PH modifying agent and the chelating agent are stored in the PH container 500 and the chelating agent container 400 at a higher concentration than the concentration of the PH modifying agent and the chelating agent in the circulating reservoir 200 during use, so that it is possible to maintain the concentrations of the PH modifying agent and the chelating agent in the reservoir 200 constant.
To measure the polishing rate, the thickness of the reclaimed wafer before and after polishing was measured using a dial gauge. Finally, the silicon polishing rate is stably maintained at 100 batches of measurement
In order to monitor the content of metal impurities on the surface of the regenerated wafer, the surface of the regenerated wafer is treated by HF acid, and then the solution of HF is analyzed for the concentration of metal ions by ICP-MS, wherein the concentration of Cu metal impurities on the surface of the polished silicon wafer is low when the conductivity is monitored and the addition amount of EDTA is maintained.
In this embodiment, as shown in fig. 1, the polishing liquid in the liquid storage container 200 can enter the polishing machine 100 through a pipeline by the action of the fourth metering pump 600. The slurry is filtered by the filter 700 to remove some large particles. The polishing liquid flows back into the liquid storage container 200 through the pipeline after being polished by the polishing machine 100. Before polishing starts, the silica sol liquid stored in the silica sol container 300 is pumped into the liquid storage container 200 through the pipe by the first metering pump 310. Note that the silica sol in the silica sol container 300 is drawn into the reservoir 200 only when the initial polishing solution is initially prepared, and is not added to the reservoir 200 after polishing is started. In addition, the storage container 200 is connected with the chelating agent container 400 through a pipeline, and the chelating agent container 400 stores the concentrated solution of the chelating agent. The PH container 500 stores a concentrated solution of a PH adjusting agent, which is introduced into the reservoir container 200 through a pipe by the third metering pump 510. An in-line PH meter 210 is mounted in the reservoir 200. When the pH drops below a threshold value, the associated third metering pump 510 is operated to deliver a corresponding volume of pH adjuster concentrate from the container 8 to the reservoir 200. When the pH reaches a certain value, the third metering pump 510 stops operating. An in-line conductivity meter 220 is additionally installed in the reservoir 200. When the conductivity drops to a threshold value, the associated second metering pump 410 is operated to deliver a corresponding volume of chelant concentrate to the reservoir 200. When the conductivity rises to a certain value, the second metering pump 410 stops operating. The reservoir 200 contains a mechanical paddle device to adequately agitate the circulating fluid.
The polishing machine 100 used in this embodiment is a single-side polishing machine 100, as shown in fig. 2, and includes a tray 110 capable of rotating clockwise, and a non-woven fabric polishing pad 120 is attached to the tray 110 by strong double-sided adhesive. The reclaimed wafer is attached to the ceramic disk 140 by wax, and the polisher head 130 applies downward pressure to compress the ceramic disk 140 so that the reclaimed wafer is in intimate contact with the polishing pad 120 to generate a rubbing action. The outlet pipe 150 sprays polishing liquid containing polishing particles through the spray head 160, and the polishing liquid can enter into the gap between the wafer and the polishing pad 120 to perform a polishing action on the surface of the reclaimed wafer.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (6)
1. A rough polishing apparatus for reclaiming wafers, comprising: the device comprises a polishing machine, a liquid storage container, a silica sol container, a chelating agent container and a PH container, wherein the silica sol container is connected with the liquid storage container through a first metering pump, the chelating agent container is connected with the liquid storage container through a second metering pump, the PH container is connected with the liquid storage container through a third metering pump, and an online PH meter and an online conductivity meter are arranged in the liquid storage container; the online PH meter is in control connection with the third metering pump, and the online conductivity meter is in control connection with the second metering pump; the liquid inlet end of the polishing machine is connected with the liquid storage container through a fourth metering pump, and the liquid storage end of the polishing machine is communicated with the liquid storage container.
2. The rough polishing apparatus for recycled wafers as recited in claim 1, wherein a filter is connected between the inlet of the polishing machine and the fourth metering pump.
3. The rough polishing apparatus for recycled wafers as recited in claim 1, wherein a stirring device is disposed in the liquid storage container.
4. The rough polishing apparatus for recycled wafers as recited in claim 2, wherein the polishing machine comprises a tray, a polishing pad, a polishing head, a ceramic plate, and a liquid outlet pipe, the liquid outlet pipe is connected to the filter, the liquid outlet end of the tray is connected to the liquid storage container, the polishing pad is disposed on the tray, the polishing head is elevatably disposed above the tray, the ceramic plate is disposed at the bottom of the polishing head, and the liquid outlet pipe is disposed at a side of the polishing head and directly above the tray.
5. The rough polishing apparatus for recycling wafers as set forth in claim 4, wherein a shower head is provided at an end of said drain pipe.
6. The rough polishing apparatus for polishing recycled wafers as claimed in claim 4 or 5, wherein the polishing pad is made of non-woven fabric.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121737676.0U CN215357898U (en) | 2021-07-28 | 2021-07-28 | Coarse polishing equipment for recycled wafers |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121737676.0U CN215357898U (en) | 2021-07-28 | 2021-07-28 | Coarse polishing equipment for recycled wafers |
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| CN215357898U true CN215357898U (en) | 2021-12-31 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115505339A (en) * | 2022-10-31 | 2022-12-23 | 上海新昇半导体科技有限公司 | Recycling method of coarse polishing solution |
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2021
- 2021-07-28 CN CN202121737676.0U patent/CN215357898U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115505339A (en) * | 2022-10-31 | 2022-12-23 | 上海新昇半导体科技有限公司 | Recycling method of coarse polishing solution |
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