CN111890132B - Process for realizing three-step polishing of large-size silicon wafer for MEMS (micro-electromechanical systems) on single polishing machine - Google Patents

Process for realizing three-step polishing of large-size silicon wafer for MEMS (micro-electromechanical systems) on single polishing machine Download PDF

Info

Publication number
CN111890132B
CN111890132B CN202010783268.2A CN202010783268A CN111890132B CN 111890132 B CN111890132 B CN 111890132B CN 202010783268 A CN202010783268 A CN 202010783268A CN 111890132 B CN111890132 B CN 111890132B
Authority
CN
China
Prior art keywords
polishing
solution
rough
deionized water
wafer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010783268.2A
Other languages
Chinese (zh)
Other versions
CN111890132A (en
Inventor
陈晨
杨洪星
索开南
李聪
庞炳远
杨静
王雄龙
张伟才
赵�权
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CETC 46 Research Institute
Original Assignee
CETC 46 Research Institute
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by CETC 46 Research Institute filed Critical CETC 46 Research Institute
Priority to CN202010783268.2A priority Critical patent/CN111890132B/en
Publication of CN111890132A publication Critical patent/CN111890132A/en
Application granted granted Critical
Publication of CN111890132B publication Critical patent/CN111890132B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B29/00—Machines or devices for polishing surfaces on work by means of tools made of soft or flexible material with or without the application of solid or liquid polishing agents
    • B24B29/02—Machines or devices for polishing surfaces on work by means of tools made of soft or flexible material with or without the application of solid or liquid polishing agents designed for particular workpieces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B57/00—Devices for feeding, applying, grading or recovering grinding, polishing or lapping agents
    • B24B57/02—Devices for feeding, applying, grading or recovering grinding, polishing or lapping agents for feeding of fluid, sprayed, pulverised, or liquefied grinding, polishing or lapping agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
    • B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
    • B81C1/00444—Surface micromachining, i.e. structuring layers on the substrate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
    • B81C1/005—Bulk micromachining
    • 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
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
    • H01L21/30625—With simultaneous mechanical treatment, e.g. mechanico-chemical polishing

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)

Abstract

The invention provides a process for realizing three-step polishing of a large-size silicon wafer for MEMS (micro-electromechanical systems), which is implemented on a single polishing machine, and comprises three steps of coarse polishing, middle polishing and fine polishing, wherein the same polishing cloth is used in each polishing step, polishing solutions with different proportions and concentrations are used in different polishing steps, and the corresponding effect of each polishing step is realized by matching and adjusting all process parameters among the polishing steps. The total thickness variation of the wafer polished in this way can be maintained to a level of 2 μm or less, and the flatness can be maintained to a level of 0.5 μm or less, effectively improving the processing efficiency.

Description

Process for realizing three-step polishing of large-size silicon wafer for MEMS (micro-electromechanical systems) on single polishing machine
Technical Field
The invention relates to a semiconductor silicon material processing technology, in particular to a process for realizing three-step polishing of a large-size silicon wafer for an MEMS (micro-electromechanical system) on a single polishing machine, which is a process method for realizing rough polishing, medium polishing and fine polishing of the large-size silicon wafer on the single polishing machine.
Background
The silicon-based MEMS technology has great significance for the modernization of national defense technology and becomes a technology preferentially developed by all military and strong countries. Silicon-based MEMS technology can be broadly divided into two technology routes, namely surface micromachining and bulk silicon machining.
The main characteristic of the bulk silicon MEMS processing technology is that the movable microstructure with larger longitudinal dimension can be obtained by deep etching of the silicon substrate material. The surface MEMS processing technology is mainly used for finishing the manufacture of MEMS devices by growing a plurality of layers of films such as silicon oxide, silicon nitride, polysilicon and the like on a silicon wafer. The movable microstructure obtained by the surface process has smaller longitudinal dimension, but has better compatibility with the IC process, and is easy to realize monolithic integration with a circuit. Both of the above two technical routes require silicon materials to have the basic characteristics of high flatness, which is the basis for realizing device precision, and double-side polishing, which is to meet the requirements of processes such as double-side photolithography. In addition, with the increasing military requirements, the MEMS devices are developing toward smaller mass, higher precision and lower cost, and the substrate silicon material is also developing toward large size, which makes the requirements for "ultra-thin and high flatness" of the large size substrate silicon material more strict.
The double-sided polishing process in the processing process of large-size silicon substrate materials is a key process for restricting the flatness of ultrathin silicon wafers, and the high flatness characteristic of the wafers is mainly realized by high-precision chemical mechanical polishing and is closely related to the morphology of polishing cloth, the state of polishing solution, the polishing pressure, the rotating speed and other processes. At present, the domestic double-side polishing manufacturing technology of large-size silicon materials is limited, the control means of precise polishing is very complicated, and the main measures are that a traditional double-side polishing machine is used for rough polishing to be thinned to a certain thickness, then a single-side rough polishing machine is used for rough polishing until a surface damage layer is completely removed, and finally a single-side finishing polishing machine is used for finish polishing until the surface reaches a high-quality state. The polishing mode has the advantages of low automation degree, unstable geometric precision and surface quality of products, low production efficiency and yield, difficulty in meeting the requirement of mass supply and restriction on the development of MEMS processing technology in China.
Disclosure of Invention
The invention aims to overcome the defects of the existing double-sided polishing technology and improve the production efficiency and the yield of large-size silicon wafers for high-precision and high-surface-quality MEMS (micro electro mechanical systems), and particularly develops a process for realizing three-step polishing of the large-size silicon wafers for the MEMS on a single polishing machine, wherein the three-step polishing comprises rough polishing, middle polishing and fine polishing, the three steps are processed on the same polishing machine, the same polishing cloth is used in each polishing step, polishing solutions with different proportions and concentrations are used in different polishing steps, and the required effect of each polishing step is realized by continuous adjustment among the polishing steps and the matching of each process parameter.
The technical scheme adopted by the invention is as follows: the three-step polishing process for the large-size silicon wafer for the MEMS is realized on a single polishing machine, and is characterized in that the three-step polishing comprises rough polishing, middle polishing and fine polishing, the three steps are processed on the same polishing machine, and the same polishing cloth is used in each polishing step; the method comprises the following specific steps:
the method comprises the following steps: selecting polishing cloth, and preparing a coarse polishing solution, a medium polishing solution and a fine polishing solution;
rough polishing solution: NP6504 colloidal solution: hydrogen peroxide: deionized water = (1-1.2): (1 ± 0.2): (20 ± 2);
and (3) medium polishing solution: SR330 colloidal solution: hydrogen peroxide: deionized water = (1-1.2): (0.8 ± 0.1): (30 ± 2);
fine polishing solution: NP8040 colloidal solution: hydrogen peroxide: deionized water = (1-1.2): (0.3-0.4): (20 ± 2);
the polishing cloth is SUBA800 or SUBA 600;
step two: loading a silicon wafer, namely placing the wandering star wheel on a polishing machine, loading the silicon wafer into the hole of the wandering star wheel, and tightly attaching polishing cloth to the upper disc and the lower disc of the polishing machine;
step three: rough polishing, setting various parameters of the rough polishing;
using a rough polishing solution, wherein the flow rate of the polishing solution is 1.8-2.0L/min, the pressure is 4.0-4.5 psi, the rotating speed is 12-20 RPM, turning on a polishing solution pump switch, lowering the polishing head onto a chassis, setting the first rough polishing time to be 10-20 min, pressing a start button to start the first rough polishing, pressing a stop button after the first rough polishing is finished, turning off the polishing solution pump switch, measuring the thickness of a wafer in a pumping mode, calculating the polishing rate, setting the second rough polishing time according to the polishing rate and the residual rough polishing removal amount, and performing the second rough polishing;
step four: water throwing;
opening a deionized water switch, lowering a polishing head onto a chassis, wherein the flow rate of deionized water is 8.0-10L/min, the pressure is 4.0-4.5 psi, the rotating speed is 10-12 RPM, the polishing time is set to be 20-30 s, and after the set time is reached, pressing a stop button to close the deionized water switch;
step five: middle polishing, wherein parameters of the middle polishing are set;
when the polishing solution is used, the flow rate of the polishing solution is 1.3-1.5L/min, the pressure is 3.0-4.0 psi, the rotating speed is 10-12 RPM, a polishing solution pump switch is turned on, the polishing head is lowered onto a chassis, the first middle polishing time is set to be 10-20 min, a start button is pressed to start first middle polishing, a stop button is pressed after the first middle polishing is finished, the polishing solution pump switch is turned off, the thickness of a wafer is measured in a pumping mode, the polishing rate is calculated, the second middle polishing time is set according to the polishing rate and the residual middle polishing removal amount, and second middle polishing is carried out;
step six: water polishing, turning on a deionized water switch, lowering a polishing head onto a chassis, setting the flow of deionized water to be 8.0-10L/min, the pressure to be 3.0-4.0 psi, the rotating speed to be 8-12 RPM, setting the polishing time to be 20-30 s, pressing a stop button after the set time is reached, and turning off the deionized water switch;
step seven: fine polishing, wherein each parameter of the fine polishing is set;
using a fine polishing solution, wherein the flow rate of the polishing solution is 1.0-1.3L/min, the pressure is 0psi, the rotating speed is 10-12 RPM, and the polishing time is set to be 7-10 min;
turning on a polishing liquid pump switch, lowering a polishing head onto a chassis, pressing a start button, starting a fine polishing program, pressing a stop button after the fine polishing is finished, and turning off the polishing liquid pump switch;
step eight: and unloading the silicon wafer, taking out the wafer in the planetary wheel after polishing, and putting the wafer in a specified position.
The invention has the advantages and effects that: (1) according to the traditional method, a double-sided polishing machine, a single-sided rough polishing machine and a single-sided fine polishing machine are respectively used for three-step polishing, after a wafer is thinned by the double-sided polishing machine, the Total Thickness Variation (TTV) can reach the level of less than or equal to 2 mu m, the flatness (TIR) can reach the level of less than or equal to 0.5 mu m, once the wafer is continuously processed on the single-sided rough polishing machine and the single-sided fine polishing machine, the total thickness variation and the flatness can be seriously deteriorated, and the requirements of high precision and high flatness of the silicon wafer for MEMS (micro-electromechanical systems) can not be met. The invention realizes three-step polishing of coarse, medium and fine on a single polishing machine, each polishing step uses the same polishing cloth, different polishing steps use polishing solutions with different proportions and concentrations, and the corresponding effect of each polishing step is realized by continuous adjustment among the polishing steps and the matching of each process parameter, so that the total thickness change of the wafer can be kept to the level of less than or equal to 2 mu m, the flatness can be kept to the level of less than or equal to 0.5 mu m, and the geometric precision level of the silicon wafer is effectively improved.
(2) According to the method, the wafers are not unloaded when the polishing steps are connected, and the processing efficiency is improved through effective connection among the polishing steps.
(3) The method avoids the complicated manual transfer process of the wafer in the traditional polishing process, effectively reduces the exposure time of the wafer in the air, reduces the contamination of the surface of the wafer, can effectively improve the surface quality level of the silicon wafer, and improves the qualification rate.
Detailed Description
The technical solution of the present invention is described in detail below with reference to examples:
example 1: wafer to be polished 30 pieces, diameter: (150 ± 0.1) mm, current thickness: 440 μm;
polishing requirements: thickness: (400 +/-2) mum (coarse polishing removal amount is 30μm, middle polishing removal amount is 10μm), total thickness variation is less than or equal to 2μm, and flatness is as follows: less than or equal to 0.5 mu m, roughness: less than or equal to 0.3 nm.
Three-step polishing was performed using an imported AC1500 model double-side polisher, the wafers were tested for geometry using a Napson sorter, and the wafer thickness was measured using a Proforma300 wafer thickness test system.
The method comprises the following steps: selecting polishing cloth: SUBA 800.
Preparing a rough polishing solution: NP6504 colloidal solution: hydrogen peroxide: deionized water = 1: 1: 20;
and (3) medium polishing solution: SR330 colloidal solution: hydrogen peroxide: deionized water = 1: 0.8: 30, of a nitrogen-containing gas;
fine polishing solution: NP8040 colloidal solution: hydrogen peroxide: deionized water = 1: 0.4: 20.
step two: and loading the wafer. The prepared 30 wafers are loaded on the planetary wheels, and each group of the planetary wheels can be loaded with 5 wafers, and the total number of the planetary wheels is 6.
Step three: and (5) rough polishing. The coarse slurry was used, setting slurry flow at 2.0L/min, pressure at 4.0psi, and rotation at 15 RPM. And turning on a polishing liquid pump switch, lowering the polishing head onto the chassis, setting the primary rough polishing time for 20min, pressing a start button to start primary rough polishing, pressing a stop button after the primary rough polishing is finished, and turning off the polishing liquid pump switch. The thickness of the sample 1 piece is 430 μm, the polishing rate is 0.5 μm/min, the residual rough polishing removal amount is 20 μm, the secondary rough polishing time is set to be 40min, and the piece is polished to the thickness of (410 +/-1) μm.
Step four: and (5) water throwing. Turning on a deionized water switch, lowering a polishing head onto a chassis, setting the flow of deionized water to be 8.0L/min, the pressure to be 4.0psi and the rotating speed to be 15RPM, pressing a start button, starting water polishing, setting polishing time to be 30s, pressing a stop button after the set time is reached, and turning off the deionized water switch.
Step five: and (4) polishing. When the polishing solution is used, the flow rate of the polishing solution is set to be 1.5L/min, the pressure is 3.0psi, the rotating speed is 10RPM, a polishing solution pump switch is turned on, the polishing head is lowered onto a chassis, the first intermediate polishing time is set for 20min, a start button is pressed to start the first intermediate polishing, and after the first intermediate polishing is finished, a stop button is pressed to turn off the polishing solution pump switch. The thickness of a sample 1 piece is 405 μm, the polishing rate is 0.25 μm/min, the polishing removal amount of the residual medium is 5 μm, the secondary medium polishing time is set to be 20min, and the piece is polished to the thickness of (400 +/-1) μm.
Step six: and (5) water throwing. Turning on a deionized water switch, lowering a polishing head onto a chassis, setting the flow of deionized water to be 8.0L/min, the pressure to be 3.0psi and the rotating speed to be 10RPM, pressing a start button, starting water polishing, setting polishing time to be 30s, pressing a stop button after the set time is reached, and turning off the deionized water switch.
Step seven: and (7) fine polishing. And (3) using the fine polishing solution, turning on a polishing solution pump switch, lowering the polishing head onto the chassis, setting the flow rate of the polishing solution to be 1.0L/min, the pressure to be 0psi and the rotating speed to be 10RPM, pressing a start button to start fine polishing, setting the polishing time to be 10min, pressing a stop button after the set time is reached, turning off the polishing solution pump switch, and measuring the thickness of 1 piece to be 400 microns.
Step eight: and (4) unloading the silicon wafer. And after polishing, taking out the wafers in the wandering star wheel, and putting the wandering star wheel into a designated water tank.
After the wafer polished in the three steps is subjected to normal pre-cleaning and final cleaning processes, the wafer is dried, the surface quality of the wafer is visually inspected, the thickness, total thickness variation, local flatness and roughness of the wafer are tested, and test data are shown in table 1.
TABLE 1 test data
Tablet number Surface quality Thickness/mum Total thickness variation/. mu.m Flatness/μm Roughness/nm
1 Qualified 400 0.83 0.22 0.1
2 Qualified 401 0.68 0.31 0.09
3 Qualified 400 0.86 0.20 0.20
4 Qualified 400 0.52 0.31 0.11
5 Qualified 400 0.67 0.19 0.2
6 Contamination by 401 0.74 0.34 0.26
7 Qualified 400 0.51 0.20 0.17
8 Qualified 399 0.64 0.31 0.15
9 Qualified 399 0.61 0.29 0.16
10 Bright spot 400 0.52 0.31 0.10
11 Qualified 401 0.81 0.39 0.20
12 Qualified 400 0.54 0.13 0.22
13 Qualified 400 0.57 0.21 0.14
14 Qualified 399 0.68 0.38 0.16
15 Qualified 400 0.69 0.29 0.11
16 Qualified 400 0.65 0.30 0.13
17 Qualified 400 0.56 0.11 0.20
18 Qualified 401 0.61 0.34 0.21
19 Qualified 400 0.61 0.30 0.17
20 Qualified 400 0.42 0.32 0.15
21 Qualified 400 0.55 0.31 0.24
22 Qualified 399 0.33 0.24 0.20
23 Qualified 400 0.46 0.38 0.09
24 Qualified 399 0.41 0.27 0.14
25 Qualified 401 0.45 0.10 0.21
26 Qualified 401 0.65 0.29 0.16
27 Qualified 400 0.56 0.14 0.14
28 Qualified 400 0.61 0.20 0.15
29 Bright spot 400 0.51 0.37 0.21
30 Qualified 400 0.63 0.21 0.18
As can be seen from the data table 1, the geometric parameters and the roughness of the wafer both meet the index requirements, the surface quality yield is 90%, the surface contamination rate is 3.3%, and the processing time is about 120 min. According to the traditional three-step polishing method, the surface quality qualified rate is less than 80%, the contamination rate is more than 8%, and the polishing time is about 140min according to the example of processing 30 polished wafers and removing 40 mu m of each wafer. It can be seen that the method of the present invention effectively improves wafer yield, reduces contamination rate, and saves about 14.3% of processing time.
Example 2: wafer to be polished 30 pieces, diameter: (150 ± 0.1) mm, current thickness: 715 μm, polishing required thickness: (675. + -.2) μm (coarse removal 30 μm, medium removal 10 μm), total thickness variation of 2 μm or less, flatness: less than or equal to 0.5 mu m, roughness: less than or equal to 0.3 nm. Three-step polishing was performed using an imported AC1500 double-side polisher, using a Napson sorter to test the geometry of the wafers, and using a Proforma wafer thickness test system to pump the wafer thickness.
The method comprises the following steps: selecting polishing cloth: SUBA 800.
Preparing a rough polishing solution: NP6504 colloidal solution: hydrogen peroxide: deionized water = 1.2: 1: 20;
and (3) medium polishing solution: SR330 colloidal solution: hydrogen peroxide: deionized water = 1.2: 0.8: 30, of a nitrogen-containing gas;
fine polishing solution: NP8040 colloidal solution: hydrogen peroxide: deionized water = 1.2: 0.4: 20.
step two: and loading the wafer. The prepared 30 wafers are loaded on the planetary wheels, and each group of the planetary wheels can be loaded with 5 wafers, and the total number of the planetary wheels is 6.
Step three: and (5) rough polishing. The method comprises the steps of using rough polishing liquid, setting the flow rate of the polishing liquid to be 2.0L/min, setting the pressure to be 4.0psi and setting the rotating speed to be 15RPM, turning on a polishing liquid pump switch, lowering a polishing head onto a chassis, setting the first rough polishing time to be 20min, pressing a start button, starting the first rough polishing, pressing a stop button after the first rough polishing is finished, and turning off the polishing liquid pump switch. The thickness of the 1 piece is 703 μm by sampling, the polishing rate is 0.6 μm/min, the residual rough polishing removal amount is 18 μm, the secondary rough polishing time is set for 30min, and the piece is polished to the thickness of (685 +/-1) μm.
Step four: and (5) water throwing. Turning on a deionized water switch, lowering a polishing head onto a chassis, setting the flow of deionized water to be 8.0L/min, the pressure to be 4.0psi and the rotating speed to be 15RPM, pressing a start button, starting water polishing, setting polishing time to be 30s, pressing a stop button after the set time is reached, and turning off the deionized water switch.
Step five: and (4) polishing. When the polishing solution is used, the flow rate of the polishing solution is set to be 1.5L/min, the pressure is 3.0psi, the rotating speed is 15RPM, a polishing solution pump switch is turned on, the polishing head is lowered onto a chassis, the first intermediate polishing time is set for 20min, a start button is pressed to start the first intermediate polishing, and after the first intermediate polishing is finished, a stop button is pressed to turn off the polishing solution pump switch. The thickness of 1 piece is 679 μm by sampling, the polishing rate is 0.3 μm/min, the polishing removal amount of the residual medium is 4 μm, the polishing time of the secondary medium is set to be 13min, and the piece is polished to the thickness of (675 +/-1) μm.
Step six: and (5) water throwing. Turning on a deionized water switch, lowering a polishing head onto a chassis, setting the flow of deionized water to be 8.0L/min, the pressure to be 3.0psi and the rotating speed to be 10RPM, pressing a start button, starting water polishing, setting polishing time to be 30s, pressing a stop button after the set time is reached, and turning off the deionized water switch.
Step seven: and (7) fine polishing. And (3) using the fine polishing solution, turning on a switch of a polishing solution pump, lowering the polishing head onto the chassis, setting the flow rate of the polishing solution to be 1.0L/min, the pressure to be 0psi and the rotating speed to be 10RPM, pressing a start button to start fine polishing, setting the polishing time to be 10min, pressing a stop button after the set time is reached, turning off the switch of the polishing solution pump, and measuring the thickness of 1 piece to be 675 microns.
Step eight: and (4) unloading the silicon wafer. And after polishing, taking out the wafers in the wandering star wheel, and putting the wandering star wheel into a designated water tank.
After the wafer polished in the three steps is subjected to normal pre-cleaning and final cleaning processes, the wafer is dried, the surface quality of the wafer is visually inspected, the thickness, total thickness change, local flatness and roughness of the wafer are tested, and test data are shown in table 2.
TABLE 2 test data
Tablet number Surface quality Thickness/mum Total thickness variation/. mu.m Flatness/μm Roughness/nm
1 Qualified 675 0.53 0.12 0.12
2 Qualified 675 0.48 0.17 0.29
3 Bright spot 674 0.36 0.10 0.10
4 Qualified 674 0.42 0.21 0.15
5 Qualified 675 0.37 0.19 0.24
6 Qualified 674 0.24 0.14 0.16
7 Bright spot 675 0.51 0.20 0.27
8 Qualified 676 0.34 0.11 0.15
9 Qualified 674 0.61 0.09 0.26
10 Qualified 675 0.52 0.11 0.14
11 Qualified 675 0.41 0.09 0.22
12 Contamination by 676 0.44 0.13 0.21
13 Qualified 675 0.27 0.21 0.24
14 Qualified 675 0.38 0.18 0.14
15 Qualified 676 0.39 0.19 0.04
16 Qualified 675 0.55 0.20 0.14
17 Qualified 675 0.46 0.21 0.22
18 Bright spot 675 0.41 0.24 0.21
19 Qualified 675 0.31 0.30 0.07
20 Qualified 676 0.22 0.22 0.10
21 Qualified 674 0.35 0.19 0.21
22 Qualified 674 0.33 0.14 0.30
23 Qualified 675 0.46 0.08 0.19
24 Qualified 674 0.41 0.07 0.15
25 Qualified 674 0.45 0.10 0.11
26 Qualified 675 0.25 0.09 0.13
27 Qualified 675 0.26 0.04 0.14
28 Qualified 676 0.21 0.20 0.25
29 Qualified 675 0.31 0.17 0.01
30 Qualified 675 0.33 0.15 0.11
As can be seen from the data table 2, the geometric parameters and the roughness of the wafer both meet the index requirements, the surface quality yield is 86.6%, the surface contamination rate is 3.3%, and the processing time is about 120 min. According to the traditional three-step polishing method, the surface quality qualified rate is less than 80%, the contamination rate is more than 8%, and the polishing time is about 140min according to the example of processing 30 polished wafers and removing 40 mu m of each wafer. It can be seen that the method of the present invention effectively improves wafer yield, reduces contamination rate, and saves about 14.3% of processing time.
Example 3: wafer to be polished 36 pieces, diameter: (200 ± 0.1) mm, current thickness: 765 μm, polishing thickness: (725 ± 2) μm (coarse removal 30 μm, medium removal 10 μm), total thickness variation of 2 μm or less, flatness: less than or equal to 0.5 mu m, roughness: less than or equal to 0.3 nm. Three-step polishing was performed using an imported AC1500 double-side polisher, using a Napson sorter to test the geometry of the wafers, and using a Proforma wafer thickness test system to pump the wafer thickness.
The method comprises the following steps: selecting polishing cloth: SUBA 600.
Preparing a rough polishing solution: NP6504 colloidal solution: hydrogen peroxide: deionized water = 1: 1: 20;
and (3) medium polishing solution: SR330 colloidal solution: hydrogen peroxide: deionized water = 1: 0.8: 30, of a nitrogen-containing gas;
fine polishing solution: NP8040 colloidal solution: hydrogen peroxide: deionized water = 1: 0.4: 20.
step two: and loading the wafer. The prepared 36 wafers are divided into two groups, each group comprises 18 wafers, the first group of 18 wafers are loaded on the planetary wheel, and each set of planetary wheel can be loaded with 3 wafers and 6 sets of planetary wheels.
Step three: and (5) rough polishing. The method comprises the steps of using rough polishing liquid, setting the flow rate of the polishing liquid to be 2.0L/min, setting the pressure to be 4.5psi, setting the rotating speed to be 15RPM, turning on a polishing liquid pump switch, lowering a polishing head onto a chassis, setting the first rough polishing time to be 20min, pressing a start button, starting the first rough polishing, pressing a stop button after the first rough polishing is finished, and turning off the polishing liquid pump switch. Measuring the thickness of 1 piece by drawing to 757 μm, polishing rate to 0.4 μm/min, removing amount of residual rough polishing to 22 μm, setting secondary rough polishing time to 55min, and polishing to (735 + -1) μm.
Step four: and (5) water throwing. Turning on a deionized water switch, lowering a polishing head onto a chassis, setting the flow of deionized water to be 8.0L/min, the pressure to be 4.0psi and the rotating speed to be 15RPM, pressing a start button, starting water polishing, setting polishing time to be 30s, pressing a stop button after the set time is reached, and turning off the deionized water switch.
Step five: and (4) polishing. When the polishing solution is used, the flow rate of the polishing solution is set to be 1.5L/min, the pressure is 4.0psi, the rotating speed is 10RPM, a polishing solution pump switch is turned on, the polishing head is lowered onto a chassis, the first intermediate polishing time is set for 20min, a start button is pressed to start the first intermediate polishing, and after the first intermediate polishing is finished, a stop button is pressed to turn off the polishing solution pump switch. The thickness of the sample 1 piece is 732 μm, the polishing rate is 0.15 μm/min, the polishing removal amount of the residual medium is 7 μm, the secondary medium polishing time is set to be 46min, and the polishing is carried out until the thickness is (725 +/-1) μm.
Step six: and (5) water throwing. Turning on a deionized water switch, lowering a polishing head onto a chassis, setting the flow of deionized water to be 8.0L/min, the pressure to be 3.0psi and the rotating speed to be 10RPM, pressing a start button, starting water polishing, setting polishing time to be 30s, pressing a stop button after the set time is reached, and turning off the deionized water switch.
Step seven: and (7) fine polishing. And (3) using the fine polishing solution, turning on a polishing solution pump switch, lowering the polishing head onto the chassis, setting the flow rate of the polishing solution to be 1.3L/min, the pressure to be 0psi and the rotating speed to be 10RPM, pressing a start button to start fine polishing, setting the polishing time to be 10min, pressing a stop button after the set time is reached, turning off the polishing solution pump switch, and measuring the thickness of 1 piece to be 725 micrometers.
Step eight: and (4) unloading the silicon wafer. And after polishing, taking out the wafers in the wandering star wheel, and putting the wandering star wheel into a designated water tank.
Step nine: and (4) loading 18 second groups of wafers on the planetary wheels, wherein each set of planetary wheels can be loaded with 3 wafers and 6 sets of planetary wheels, and then processing according to the steps from two to eight.
After the wafer polished in the three steps is subjected to normal pre-cleaning and final cleaning processes, the wafer is dried, the surface quality of the wafer is visually inspected, the thickness, total thickness variation, local flatness and roughness of the wafer are tested, and test data are shown in table 3.
TABLE 3 test data
Tablet number Surface quality Thickness/mum Total thickness variation/. mu.m Flatness/μm Roughness/nm
1 Qualified 725 1.03 0.32 0.22
2 Qualified 724 0.98 0.47 0.09
3 Bright spot 724 0.86 0.50 0.11
4 Qualified 724 0.72 0.31 0.12
5 Qualified 725 1.07 0.39 0.24
6 Qualified 726 1.34 0.44 0.06
7 Bright spot 725 1.01 0.20 0.07
8 Qualified 726 1.24 0.31 0.25
9 Qualified 726 0.81 0.49 0.06
10 Qualified 725 0.92 0.21 0.04
11 Qualified 725 0.71 0.29 0.12
12 Contamination by 726 0.84 0.33 0.11
13 Qualified 725 0.67 0.41 0.12
14 Qualified 725 0.98 0.28 0.24
15 Qualified 726 1.39 0.49 0.17
16 Qualified 725 1.25 0.30 0.24
17 Qualified 724 1.06 0.31 0.24
18 Qualified 724 1.11 0.50 0.15
19 Qualified 724 1.01 0.40 0.24
20 Qualified 726 1.42 0.42 0.21
21 Contamination by 726 0.85 0.59 0.21
22 Qualified 724 0.73 0.24 0.25
23 Qualified 726 0.94 0.38 0.09
24 Qualified 724 0.71 0.27 0.15
25 Qualified 724 0.95 0.30 0.21
26 Qualified 725 0.65 0.29 0.11
27 Qualified 725 0.76 0.44 0.24
28 Qualified 726 1.21 0.30 0.14
29 Qualified 725 1.21 0.27 0.15
30 Qualified 724 1.23 0.35 0.09
31 Bright spot 724 1.05 0.24 0.11
32 Bright spot 724 1.09 0.34 0.12
33 Qualified 726 1.01 0.50 0.09
34 Qualified 726 1.24 0.44 0.13
35 Qualified 724 0.98 0.38 0.21
36 Qualified 725 0.87 0.43 0.22
As can be seen from the data table 3, the geometric parameters and the roughness of the wafer both meet the index requirements, the surface quality yield is 83.3%, the surface contamination rate is 5.5%, and the processing time is about 120 min. According to the traditional three-step polishing method, the surface quality qualified rate is less than 80%, the contamination rate is more than 8%, and the polishing time is about 150min according to the example of processing 36 polished wafers and removing 40 mu m of each wafer. The method of the invention can effectively improve the wafer yield, reduce the contamination rate and save about 20 percent of processing time.

Claims (1)

1. The three-step polishing process for the large-size silicon wafer for the MEMS is realized on a single polishing machine, and is characterized in that the three-step polishing comprises rough polishing, middle polishing and fine polishing, the three steps are processed on the same polishing machine, and the same polishing cloth is used in each polishing step; the method comprises the following specific steps:
the method comprises the following steps: selecting polishing cloth, and preparing a coarse polishing solution, a medium polishing solution and a fine polishing solution;
rough polishing solution: NP6504 colloidal solution: hydrogen peroxide: deionized water = (1-1.2): (1 ± 0.2): (20 ± 2);
and (3) medium polishing solution: SR330 colloidal solution: hydrogen peroxide: deionized water = (1-1.2): (0.8 ± 0.1): (30 ± 2);
fine polishing solution: NP8040 colloidal solution: hydrogen peroxide: deionized water = (1-1.2): (0.3-0.4): (20 ± 2);
the polishing cloth is SUBA800 or SUBA 600;
step two: loading a silicon wafer, namely placing the wandering star wheel on a polishing machine, loading the silicon wafer into the hole of the wandering star wheel, and tightly attaching polishing cloth to the upper disc and the lower disc of the polishing machine;
step three: rough polishing, setting various parameters of the rough polishing;
using a rough polishing solution, wherein the flow rate of the polishing solution is 1.8-2.0L/min, the pressure is 4.0-4.5 psi, the rotating speed is 12-20 RPM, turning on a polishing solution pump switch, lowering the polishing head onto a chassis, setting the first rough polishing time to be 10-20 min, pressing a start button to start the first rough polishing, pressing a stop button after the first rough polishing is finished, turning off the polishing solution pump switch, measuring the thickness of a wafer in a pumping mode, calculating the polishing rate, setting the second rough polishing time according to the polishing rate and the residual rough polishing removal amount, and performing the second rough polishing;
step four: water throwing;
opening a deionized water switch, lowering a polishing head onto a chassis, wherein the flow rate of deionized water is 8.0-10L/min, the pressure is 4.0-4.5 psi, the rotating speed is 10-12 RPM, the polishing time is set to be 20-30 s, and after the set time is reached, pressing a stop button to close the deionized water switch;
step five: middle polishing, wherein parameters of the middle polishing are set;
when the polishing solution is used, the flow rate of the polishing solution is 1.3-1.5L/min, the pressure is 3.0-4.0 psi, the rotating speed is 10-12 RPM, a polishing solution pump switch is turned on, the polishing head is lowered onto a chassis, the first middle polishing time is set to be 10-20 min, a start button is pressed to start first middle polishing, a stop button is pressed after the first middle polishing is finished, the polishing solution pump switch is turned off, the thickness of a wafer is measured in a pumping mode, the polishing rate is calculated, the second middle polishing time is set according to the polishing rate and the residual middle polishing removal amount, and second middle polishing is carried out;
step six: water polishing, turning on a deionized water switch, lowering a polishing head onto a chassis, setting the flow of deionized water to be 8.0-10L/min, the pressure to be 3.0-4.0 psi, the rotating speed to be 8-12 RPM, setting the polishing time to be 20-30 s, pressing a stop button after the set time is reached, and turning off the deionized water switch;
step seven: fine polishing, wherein each parameter of the fine polishing is set;
using a fine polishing solution, wherein the flow rate of the polishing solution is 1.0-1.3L/min, the pressure is 0psi, the rotating speed is 10-12 RPM, and the polishing time is set to be 7-10 min;
turning on a polishing liquid pump switch, lowering a polishing head onto a chassis, pressing a start button, starting a fine polishing program, pressing a stop button after the fine polishing is finished, and turning off the polishing liquid pump switch;
step eight: and unloading the silicon wafer, taking out the wafer in the planetary wheel after polishing, and putting the wafer in a specified position.
CN202010783268.2A 2020-08-06 2020-08-06 Process for realizing three-step polishing of large-size silicon wafer for MEMS (micro-electromechanical systems) on single polishing machine Active CN111890132B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010783268.2A CN111890132B (en) 2020-08-06 2020-08-06 Process for realizing three-step polishing of large-size silicon wafer for MEMS (micro-electromechanical systems) on single polishing machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010783268.2A CN111890132B (en) 2020-08-06 2020-08-06 Process for realizing three-step polishing of large-size silicon wafer for MEMS (micro-electromechanical systems) on single polishing machine

Publications (2)

Publication Number Publication Date
CN111890132A CN111890132A (en) 2020-11-06
CN111890132B true CN111890132B (en) 2022-04-12

Family

ID=73245420

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010783268.2A Active CN111890132B (en) 2020-08-06 2020-08-06 Process for realizing three-step polishing of large-size silicon wafer for MEMS (micro-electromechanical systems) on single polishing machine

Country Status (1)

Country Link
CN (1) CN111890132B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113001379A (en) * 2021-03-17 2021-06-22 天津中环领先材料技术有限公司 Large-size silicon wafer double-side polishing method
CN117161942A (en) * 2023-08-21 2023-12-05 浙江海纳半导体股份有限公司 Ultrathin silicon wafer thinning and polishing equipment and process

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103072073A (en) * 2012-12-13 2013-05-01 天津中环领先材料技术有限公司 Polishing process capable of maintaining long service life of silicon wafer polished section minority carrier
CN105252406A (en) * 2015-09-10 2016-01-20 上海超硅半导体有限公司 Polishing method for silicon wafer
CN107855922A (en) * 2017-10-31 2018-03-30 天津中环领先材料技术有限公司 A kind of technique for lifting 8 inches of silicon wafer geometric parameters
CN108242396A (en) * 2016-12-23 2018-07-03 有研半导体材料有限公司 A kind of processing method for reducing silicon polished surface roughness
CN111251163A (en) * 2018-11-30 2020-06-09 有研半导体材料有限公司 Processing method for polished silicon wafer with hydrophilic surface

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020086625A1 (en) * 2000-05-23 2002-07-04 Wafer Solutions, Inc. Vacuum mount wafer polishing methods and apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103072073A (en) * 2012-12-13 2013-05-01 天津中环领先材料技术有限公司 Polishing process capable of maintaining long service life of silicon wafer polished section minority carrier
CN105252406A (en) * 2015-09-10 2016-01-20 上海超硅半导体有限公司 Polishing method for silicon wafer
CN108242396A (en) * 2016-12-23 2018-07-03 有研半导体材料有限公司 A kind of processing method for reducing silicon polished surface roughness
CN107855922A (en) * 2017-10-31 2018-03-30 天津中环领先材料技术有限公司 A kind of technique for lifting 8 inches of silicon wafer geometric parameters
CN111251163A (en) * 2018-11-30 2020-06-09 有研半导体材料有限公司 Processing method for polished silicon wafer with hydrophilic surface

Also Published As

Publication number Publication date
CN111890132A (en) 2020-11-06

Similar Documents

Publication Publication Date Title
CN111890132B (en) Process for realizing three-step polishing of large-size silicon wafer for MEMS (micro-electromechanical systems) on single polishing machine
US5800725A (en) Method of manufacturing semiconductor wafers
KR100420621B1 (en) process for the surface polishing of silicon wafers
CN102528597B (en) Manufacturing process of large-diameter silicon wafer
JP4532521B2 (en) Manufacturing method of polished semiconductor wafer
CN102019582B (en) Polishing process of 8-inch polished wafers doped with silicon lightly
CN101656193B (en) Technique for processing silicon chip
CN113206007B (en) Preparation method of indium phosphide substrate
WO2015172589A1 (en) Post-treatment method for pyroelectric relaxor ferroelectric single crystal
CN110744364B (en) Double-side polishing method for large-size ultrathin lithium niobate substrate
CN107398780B (en) Double-side polishing method for wafer
US6051498A (en) Method for manufacturing a semiconductor wafer which is coated on one side and provided with a finish
CN1424746A (en) Silicon semiconductor crystal wafers and manufacturing method for multiple semiconductor crystal wafers
CN111251163B (en) Processing method for polished silicon wafer with hydrophilic surface
US6465328B1 (en) Semiconductor wafer manufacturing method
US20010039101A1 (en) Method for converting a reclaim wafer into a semiconductor wafer
CN112975578B (en) Polishing method for improving surface roughness of silicon polished wafer
CN111095491A (en) Double-side polishing method for silicon wafer
CN113192823B (en) Regeneration processing method of substrate slice after SOI bonding process
JP3943869B2 (en) Semiconductor wafer processing method and semiconductor wafer
CN106736881A (en) Wafer surface processing and treating method
WO2003046994A1 (en) Method for producing cemented wafer
JP3906688B2 (en) Polishing cloth for semiconductor wafer and polishing method
CN113611593B (en) Control method for warpage morphology of ultrathin germanium sheet
KR20090121527A (en) Recycling method of silicon wafer and its recycled divice

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant