A cleaning device for polysilicon defect detection
By using a cleaning device with a tray and mesh structure, a conical support structure, and turbulent etching technology in polycrystalline silicon defect detection, the problem of uneven etching caused by PVDF fixtures was solved, achieving uniform etching and accurate defect detection on the surface of polycrystalline silicon wafers.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU XINHUA SEMICON TECH CO LTD
- Filing Date
- 2025-06-19
- Publication Date
- 2026-06-23
AI Technical Summary
In the prior art, when PVDF fixtures hold polycrystalline silicon wafers, local oxidation or crystallization occurs, which masks the real defects. In addition, the etching rate is uneven, making it impossible to accurately detect dense layer defects and needle-like crystal distribution on the surface of the silicon wafer.
The cleaning device adopts a tray and mesh structure. The tray has multiple through holes and support structures. The support is conical with a top of less than 1 mm2. Through point contact and turbulent etching, surface contact blockage is avoided, ensuring uniform penetration of acid. Turbulence is formed at the contact point between the support and the silicon wafer, promoting etching uniformity.
Uniform etching of polycrystalline silicon wafer surface is achieved, which significantly improves the accuracy of dense layer defect detection and the accuracy of needle crystal distribution. The etching uniformity deviation is less than 5%, and the detection results are more reliable.
Smart Images
Figure CN224402047U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electronic-grade polysilicon processing and defect control technology, and in particular to a cleaning device for polysilicon defect detection. Background Technology
[0002] In the preparation of electronic-grade zone-melted polycrystalline silicon, accurate detection of surface defects on silicon wafers is a core aspect of quality control. This type of polycrystalline silicon must meet extreme purity and crystal integrity requirements, including an ultra-low needle-like crystal ratio and an ultra-low density of dense layer defects. Currently, the industry uses acid etching to expose surface defects on silicon wafers. During this process, large polycrystalline silicon wafers are held in PVDF fixtures and immersed in an acidic etching bath. After etching is complete, the wafers are transferred to a high-purity water bath to terminate the reaction.
[0003] When using PVDF fixtures, a closed micro-gap is formed in the contact area between the PVDF fixture and the silicon wafer. The acid solution is locally retained and evaporated and concentrated at the clamping point, resulting in local oxidation or crystallization, which masks the real defects and is misjudged as needle-like crystal distribution. Secondly, the etching rate is reduced in the mechanically shielded contact area of the PVDF fixture, making it impossible to accurately expose the dense layer defects from the silicon core to the growth layer. Utility Model Content
[0004] The purpose of this invention is to provide a cleaning device for detecting defects in polycrystalline silicon, addressing the shortcomings of existing technologies.
[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0006] A cleaning apparatus for detecting defects in polycrystalline silicon includes a tray and a mesh structure formed thereon, as well as a support structure corresponding to the mesh structure.
[0007] The mesh structure includes multiple through holes evenly distributed on the tray, and the support structure includes supports corresponding to the through holes; the supports disrupt the flow pattern.
[0008] Two handles are symmetrically arranged along the edge of the tray.
[0009] Furthermore, the mesh structure has an opening ratio of not less than 40% on the surface of the tray.
[0010] Furthermore, a chamfered structure is provided along the edge of the through hole, and the ratio of the diameter of the through hole to the diameter of the tray is set between 1:20 and 1:12.
[0011] Furthermore, the support is configured as a conical structure, with its top end being a spherical or flat surface, and the area not exceeding 1 mm². 2 .
[0012] Furthermore, the support is disposed near the edge of the through hole, and at least three are evenly disposed along the circumference of the through hole.
[0013] Furthermore, the ratio of the bottom diameter of the support to the diameter of the through hole is set between 1:3 and 1:5.
[0014] Furthermore, both the tray and the support are integrally injection molded from PVDF material.
[0015] Furthermore, reinforcing ribs are provided at the edge of the tray, and the reinforcing ribs are arc-shaped and multiple of them are provided along the circumference of the tray.
[0016] Furthermore, the handle includes a rotating frame and a handle disposed thereon, a connecting seat is provided at the edge of the tray, one end of the rotating frame is rotatably connected to the connecting seat via a connecting shaft, and the handle is disposed at the end of the rotating frame away from the connecting seat.
[0017] The beneficial effects of this utility model are as follows:
[0018] In this application, a support structure set on a tray supports the silicon wafer, and a vertical penetration channel for acid is provided by a mesh on the tray, avoiding the problem of uneven etching caused by the physical obstruction of the silicon wafer surface by traditional clamping tools.
[0019] The support is designed with a conical structure, and its top diameter is no greater than 0.5mm. The support achieves point contact between the tray and the silicon wafer, eliminating the surface contact required in traditional wafer clamping operations. By using its tip to contact only a very small area of the silicon wafer, the support further utilizes the turbulence created by the acid at the tip to propel the wafer, allowing the contact point between the wafer and the support to undergo etching, thus preventing uneven etching that could obstruct the detection area. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the cleaning device used for detecting defects in polycrystalline silicon in this utility model;
[0022] Figure 2 This is a schematic diagram of the handle structure of the cleaning device in this utility model.
[0023] Reference numerals: 1. Tray; 11. Reinforcing rib; 2. Mesh structure; 21. Through hole; 3. Support structure; 31. Support; 4. Handle; 41. Rotating frame; 42. Handle; 43. Connecting shaft; 44. Connecting seat. Detailed Implementation
[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.
[0025] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.
[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0027] like Figure 1 and Figure 2 The cleaning device shown is for detecting defects in polycrystalline silicon. It includes a tray 1 and a mesh structure 2 formed thereon, and a support structure 3 provided corresponding to the mesh structure 2. The mesh structure 2 includes a plurality of through holes 21 evenly distributed on the tray 1, and the support structure 3 includes supports 31 provided corresponding to the through holes 21. Two handles 4 are symmetrically arranged at the edge of the tray 1.
[0028] In this application, a support structure 3 mounted on a tray 1 supports the silicon wafer, and a mesh opening on the tray 1 provides a vertical penetration channel for acid, avoiding the uneven etching problem caused by the physical obstruction of the silicon wafer surface by traditional clamping tools. By disrupting the flow pattern through the support 31, full contact between the acid and the silicon wafer can be promoted.
[0029] The support 31 is a conical structure with its top end being a spherical or flat surface, and the area is no greater than 1 mm². 2The support 31 achieves point contact between the tray 1 and the silicon wafer, eliminating the surface contact required in traditional silicon wafer clamping operations. The support 31, with its tip contacting only a very small area of the silicon wafer, further utilizes the turbulence created by the acid at the tip to propel the silicon wafer, allowing the contact point between the silicon wafer and the support 31 to undergo etching, thus avoiding uneven etching that could obstruct the detection area.
[0030] In this embodiment, the opening ratio of the mesh structure 2 on the surface of the tray 1 is not less than 40%. A chamfer structure is provided on the edge of the through hole 21, and the ratio of the diameter of the through hole 21 to the diameter of the tray 1 is set between 1:20 and 1:12.
[0031] The aperture ratio on tray 1 is ≥40%, ensuring acid penetration >95%. Combined with the tip of support 31, it guides the acid turbulence, making the Reynolds number Re >3000 (turbulent state) and the etching uniformity deviation <5%.
[0032] Specifically, the tapered support 31, with its minimal contact area and the upward thrust generated during the reaction, ensures that the polycrystalline silicon wafer does not contact the substrate during etching. Traditional clamping or direct placement methods suffer from insufficient acid penetration in the shielded area, leading to significant etching thickness deviations and making it impossible to accurately determine the density of defects in the dense layer from the silicon core to the growth layer and the area of needle-like crystals in the growth layer. This invention, through the high-density through-holes 21 and the acid turbulence guided by the tapered support 31, improves etching uniformity and significantly reduces deviations, ensuring that no defects are missed during detection.
[0033] The chamfer of the through hole 21 can reduce fluid resistance. The size design of the through hole 21 should be adapted to the size of the tray 1 to avoid the tray 1 being deformed due to the opening being too large, or the acid penetration rate being reduced due to the opening size being too small.
[0034] Furthermore, the support 31 is positioned close to the edge of the through hole 21, and at least three are evenly distributed along the circumference of the through hole 21. The ratio of the bottom diameter of the support 31 to the diameter of the through hole 21 is set between 1:3 and 1:5. The diameter of the support 31 is significantly smaller than the size of the through hole 21, ensuring that there are no dead zones during the acid flow process.
[0035] In this embodiment, both the tray 1 and the support 31 are integrally injection molded from PVDF material. It is resistant to mixed acids at 70℃ and has a mixed acid corrosion lifespan of >500 hours.
[0036] Considering that the insufficient thickness of tray 1 may cause thermal deformation in acid solution at 70°C, reinforcing ribs 11 are provided along the edge of tray 1. The reinforcing ribs 11 have an arc-shaped structure and multiple ribs are provided along the circumference of tray 1. At the same time, the reinforcing ribs 11 also serve to limit the position of the silicon wafers supported on tray 1.
[0037] In this embodiment, the handle 4 includes a rotating frame 41 and a handle 42 disposed thereon. A connecting seat 44 is provided at the edge of the tray 1. One end of the rotating frame 41 is rotatably connected to the connecting seat 44 through a connecting shaft 43. The handle 42 is disposed at the end of the rotating frame 41 away from the connecting seat 44.
[0038] During the specific implementation of the cleaning device, the polycrystalline silicon wafer is gently placed on several supports 31 on the tray 1. The handle 4 is operated to vertically immerse the tray 1 into the acid bath. The acid solution covers the surface of the silicon wafer from bottom to top through the mesh, and the spikes guide the acid solution to form turbulence, eliminating air bubbles and dead corners. The tray 1 is gently shaken at a frequency of 10 times / minute, and the spikes are used to disturb the acid solution to achieve uniform etching of the entire surface of the silicon wafer. The total acid washing time for dynamic etching is controlled between 1 minute and 5 minutes. After etching, the silicon wafer is vertically lifted by the handle 4 and quickly transferred to a water tank containing high-purity water to avoid acid spots left on the surface of the polycrystalline silicon wafer due to the reaction of the acid solution with air.
[0039] Among them, dynamic disturbance optimization shakes the tray 1 at a frequency of 10 times / minute to eliminate the "dead zone" of static etching, which significantly improves the detection rate of dense layer defects.
[0040] Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.
Claims
1. A cleaning device for detecting defects in polycrystalline silicon, characterized in that, It includes a tray (1) and a mesh structure (2) formed thereon, and a support structure (3) provided corresponding to the mesh structure (2); The mesh structure (2) includes a plurality of through holes (21) evenly distributed on the tray (1), and the support structure (3) includes a support (31) corresponding to the through holes (21), through which the flow pattern is disturbed.
2. The cleaning apparatus for detecting defects in polycrystalline silicon according to claim 1, characterized in that, The perforation rate of the mesh structure (2) on the surface of the tray (1) is not less than 40%.
3. The cleaning apparatus for detecting defects in polycrystalline silicon according to claim 1, characterized in that, A chamfered structure is provided on the edge of the through hole (21), and the ratio of the diameter of the through hole (21) to the diameter of the tray (1) is set between 1:20 and 1:
12.
4. The cleaning apparatus for detecting defects in polycrystalline silicon according to claim 1, characterized in that, The support (31) is configured as a conical structure, with its top end being a spherical or flat surface, and the area not exceeding 1 mm². 2 .
5. The cleaning apparatus for detecting defects in polycrystalline silicon according to claim 4, characterized in that, The support (31) is disposed near the edge of the through hole (21), and at least three are evenly disposed along the circumference of the through hole (21).
6. The cleaning apparatus for detecting defects in polycrystalline silicon according to claim 4, characterized in that, The ratio of the bottom diameter of the support (31) to the diameter of the through hole (21) is set between 1:3 and 1:
5.
7. The cleaning apparatus for detecting defects in polycrystalline silicon according to claim 1, characterized in that, Both the tray (1) and the support (31) are integrally injection molded from PVDF material.
8. The cleaning apparatus for detecting defects in polycrystalline silicon according to claim 1, characterized in that, A reinforcing rib (11) is provided at the edge of the tray (1). The reinforcing rib (11) has an arc-shaped structure and multiple ribs are provided along the circumference of the tray (1).
9. The cleaning apparatus for detecting defects in polycrystalline silicon according to claim 1, characterized in that, Two handles (4) are symmetrically arranged at the edge of the tray (1).
10. The cleaning apparatus for detecting defects in polycrystalline silicon according to claim 9, characterized in that, The handle (4) includes a rotating frame (41) and a handle (42) disposed thereon. A connecting seat (44) is provided at the edge of the tray (1). One end of the rotating frame (41) is rotatably connected to the connecting seat (44) through a connecting shaft (43). The handle (42) is disposed at the end of the rotating frame (41) away from the connecting seat (44).