Wafer single-side etching apparatus

Abstract

The application discloses a wafer single-side etching equipment, which comprises a processing table, a plurality of circular wafer placing openings are arranged on the processing table at intervals and used for horizontally placing wafers to be etched, a shielding cover arranged above the processing table, a spraying groove arranged below the processing table and having a closed inner cavity, and an acid mist supply device arranged below the processing table, the inner cavity of the spraying groove is communicated with all the wafer placing openings, the acid mist supply device comprises a spraying pipeline used for upward spraying, the spraying pipeline is arranged in the spraying groove, the shielding cover has a shielding surface facing the processing table, and the shielding cover has an opening state and a shielding state; when the shielding cover is in the shielding state, the shielding surface covers all the wafer placing openings and is attached to the upper surfaces of all the wafers. The etching equipment has the advantages of simple structure, small occupied space, convenient installation, convenient operation, stable running and the like, and can remarkably reduce production running and maintenance costs.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor processing, and in particular to a wafer single-side etching device. Background Art

[0002] Etching is a crucial step in the semiconductor manufacturing process. The etching process selectively corrodes or strips the surface of a semiconductor substrate or the thin film covering it according to the mask pattern or design requirements. Etching can be categorized as either wet or dry etching. Wet etching involves a chemical reaction between an etching solution and the silicon wafer or the thin film covering it, creating a textured surface on the relatively flat surface. This increases the optical path and reduces light reflection. Etching solutions can be strong acids such as diluted hydrochloric acid or hydrofluoric acid.

[0003] Wafers are important materials for making semiconductor components such as chips and solar cells. There are two types of wet etching processes for wafers: single-sided and double-sided etching. Single-sided etching refers to etching only one surface of the wafer, and no processing is performed on the surfaces of the wafer other than the surface to be etched. To achieve this goal, the etching liquid can only reach the single side designated for etching during the process. If the non-designated surface of the wafer is contaminated by the etching liquid, it will affect the overall functionality of the wafer and may even cause part of the wafer to be unusable and must be abandoned. Therefore, when the wafer undergoes a single-sided etching process, how to effectively prevent the etching liquid from contaminating the non-designated etching surface has become an issue that has been of concern to the industry.

[0004] In the prior art, there are various methods for preventing non-designated etching surfaces from being contaminated by etching solution during single-sided etching of wafers. Some technologies add a protective layer (such as photoresist or adhesive) to the non-designated etching surface of the wafer to prevent etching solution contamination during the process. However, this method requires an additional step of removing the protective layer after etching is completed, which not only increases the complexity of the process, but if the removal is not complete, residual adhesive may cause contamination of the wafer surface, or the wafer may be scratched during the protective layer removal process, which is very inconvenient. Some existing technologies allow the etching liquid to contact only the surface of the wafer to be etched during the wafer transportation in the etching tank, or after the etching liquid is absorbed by the transport roller, the etching liquid is absorbed by the capillary phenomenon to achieve a single-sided etching effect. However, this method may cause uneven adhesion of the etching liquid on the wafer, resulting in incomplete etching of the wafer. In addition, since the surface of the wafer not to be etched is not protected, during the etching process, the etching liquid generates bubbles due to the chemical action of the etching. When the bubbles burst, some of the etching liquid will splash onto the unprotected surface of the wafer not to be etched, causing etching marks. Not only can the quality of the wafer after etching be guaranteed, but it may even affect the performance of the wafer.

[0005] In view of this, how to research and develop improvements to address the shortcomings of the above-mentioned existing wafer single-side etching methods and devices so that users can use them more conveniently and the production cost is minimized has become a goal that the relevant industry needs to work hard on. Summary of the Invention

[0006] The purpose of the present invention is to provide a single-sided wafer etching device with simple operation, high etching efficiency and the ability to effectively prevent non-designated surfaces of the wafer from being contaminated by etching liquid, in order to solve the problems existing in the prior art.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A single-sided wafer etching device, the etching device includes a processing table, a plurality of swing openings for horizontally placing wafers to be etched are provided at intervals on the processing table, the swing openings are circular and match the shape of the wafers to be etched, the etching device also includes a shielding cover arranged above the processing table, a spray tank arranged below the processing table and having a closed inner cavity, and an acid mist supply device arranged below the processing table, the inner cavity of the spray tank is connected to all the swing openings, the acid mist supply device includes a spray pipeline for upward spraying, the spray pipeline is arranged in the spray tank, the shielding cover has a shielding surface facing the processing table, the shielding cover has an open state and a shielding state, when the shielding cover is in the shielding state, the shielding surface covers all the swing openings, and the shielding surface is in contact with the upper surfaces of all the wafers.

[0009] Preferably, when the shielding cover is in the shielding state, the wafer to be etched on each of the swing openings closes the swing opening.

[0010] Preferably, a circular limit platform is fixed on the inner circumferential wall of the swing opening, the inner diameter of the swing opening is greater than or equal to the diameter of the wafer to be etched, the inner diameter of the limit platform is smaller than the diameter of the wafer to be etched, the processing table has a table top, the limit platform is lower than the table top, and when the shielding cover is in the shielding state, the shielding surface is fitted against the table top.

[0011] Further preferably, the distance between the upper surface of the limiting platform and the table top is equal to the thickness of the wafer to be etched.

[0012] Preferably, the etching equipment also includes a mounting table, a mounting groove is provided on the mounting table, the processing table is fixed on the mounting table and is located in the mounting groove, the circumferential side wall of the mounting groove is higher than the upper surface of the processing table, when the shielding cover is in the shielding state, the shielding surface is lower than the circumferential side wall of the mounting groove, and the shielding cover is at least partially located in the mounting groove.

[0013] Further preferably, the shielding cover is arranged on the mounting platform so as to be relatively rotatable around a rotation center line.

[0014] Preferably, the plurality of swing openings are arranged in an array on the processing table.

[0015] Preferably, the acid mist supply device includes a hydrogen fluoride atomization box for providing hydrogen fluoride acid mist, a water atomization box for providing water mist, and a nitrogen supply mechanism for providing pressurized nitrogen. The hydrogen fluoride atomization box, the water atomization box, and the nitrogen supply mechanism are respectively connected to the spray pipeline.

[0016] Preferably, a plurality of recovery holes for recovering waste liquid are provided at intervals on the bottom of the spray tank, and the etching equipment further comprises a waste liquid recovery mechanism, which is connected to all the recovery holes.

[0017] Preferably, the etching equipment includes a shell having a closed processing space, and the processing table, the shielding cover, the spray tank and the acid mist supply device are all arranged in the processing space. The etching equipment also includes an exhaust device for discharging the gas in the processing space to the outside of the processing space, and the exhaust device includes a wind valve arranged on the shell.

[0018] Due to the application of the above technical solutions, the wafer single-sided etching equipment provided by the present invention can effectively prevent the upper surface of the wafer that is not designated to be etched from being contaminated with etching liquid by a simple and strict shielding cover, combined with the acid mist etching process, to achieve ideal single-sided etching of the wafer. The swing port is exactly matched with the wafer, stably supporting the wafer while minimizing the impact on the normal etching of the lower surface of the wafer; acid mist etching is more uniform and complete than acid immersion etching, and high-quality wafer products can be obtained, and the low density characteristics of the atomized liquid are also conducive to preventing the acid from overflowing upward and contaminating the upper surface of the wafer that is not to be etched. At the same time, the consumption of acid and pure water is greatly reduced, and etching and cleaning can be completed in sequence without moving the wafer, which is very convenient. In addition, when the etching equipment is working normally, the acid mist environment is completely sealed, which not only improves safety, but also improves the utilization rate of acid mist and reduces acid waste. The equipment itself is also provided with a safety exhaust device, and the etching process does not require manual intervention at all, with high safety performance and automation. The wafer single-side etching equipment of the present invention has a simple structure and occupies a small space. It is also easy to install, easy to operate, and runs smoothly, and can significantly reduce production operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for describing the embodiments.

[0020] AttachmentFigure 1 A schematic three-dimensional diagram of a wafer single-side etching device according to a specific embodiment of the present invention;

[0021] Attachment Figure 2 for Figure 1 A in the middle is an enlarged schematic diagram;

[0022] Attachment Figure 3 This is a schematic front view of the etching device in this embodiment, wherein the shielding cover is in an open state;

[0023] Attachment Figure 4 for Figure 3 Schematic diagram of the BB cross section;

[0024] Attachment Figure 5 for Figure 4 Enlarged schematic diagram at point C in the middle;

[0025] Attachment Figure 6 for Figure 4 Schematic diagram of the middle occluding cover in the occluding state;

[0026] Attachment Figure 7 for Figure 6 The enlarged schematic diagram of point D in the middle;

[0027] Attachment Figure 8 Schematic side view of the etching equipment in this embodiment.

[0028] Attachment Figure 9 for Figure 8 EE cross-sectional view diagram;

[0029] Among them: 100, shell; 100a, processing space; 200, mounting table; 210, mounting groove; 300, processing table; 300a, table top; 310, swing plate opening; 311, limit table; 320, spray tank; 320a, inner cavity; 321, recovery hole; 400, shielding cover; 400a, shielding surface; 410, baffle; 420, reinforcement structure; 500, acid mist supply device; 510, spray pipeline; 511, connecting pipeline; 520, hydrogen fluoride atomization box; 530, hydrogen fluoride raw liquid box; 540, water atomization box; 550, heating box; 610, air valve; 620, air intake; X, rotation center line. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art.

[0031] See also Figure 1 and Figure 2As shown, a single-side wafer etching apparatus includes a housing 100 having an enclosed processing space 100a. It should be noted that while the housing 100 shown in the figure is partially hollowed out on its sides to facilitate visualization of the internal structure of the etching apparatus, in reality, all sides of the housing 100 can be completely enclosed, or at least connected to other enclosed equipment, thereby preventing any harmful gases (such as acid mist) that may be present in the processing space 100a from escaping into the external space, thereby ensuring production safety.

[0032] Specifically, the etching apparatus includes a mounting table 200, a processing table 300, a shielding cover 400, an acid mist supply device 500, and an exhaust device, etc., which are arranged in a processing space 100a. The exhaust device is used to discharge the gas in the processing space 100a to the outside of the processing space 100a and enable ventilation. The exhaust device includes an air intake 620 arranged in the processing space 100a and a damper 610 arranged at the top of the housing 100. One end of the damper 610 is connected to the air intake 620 and can continuously suck out the exhaust gas in the processing space 100a. The other end of the damper 610 is connected to an exhaust gas treatment device (not shown) located outside the etching apparatus. The exhaust gas treatment device performs harmless treatment on the exhaust gas before discharging it into the atmosphere.

[0033] In this embodiment, a mounting groove 210 is fixed on the mounting table 200 , and the circumferential side walls of the mounting groove 210 extend upward from the mounting table 200 and enclose a rectangular space. The processing table 300 is fixed on the mounting table 200 and located in the mounting groove 210 .

[0034] See also Figure 1 As shown, the upper surface of the processing table 300 is a horizontally extending table 300a, and the table 300a is lower than the circumferential side wall of the mounting groove 210, so that the processing table 300 is located inside the above-mentioned rectangular space as a whole. A plurality of swing openings 310 for horizontally placing the wafers to be etched are provided on the table 300a at intervals. The swing openings 310 are circular and match the shape of the wafers to be etched, so that the etching equipment can realize the simultaneous processing of multiple wafers and improve the etching efficiency. In this embodiment, the plurality of swing openings 310 are arranged in a 3×4 array on the processing table 300. Of course, the specific number and arrangement of the swing openings 310 can be freely adjusted and designed according to actual needs, and the opening sizes of different swing openings 310 can be the same or different to meet the needs of wafers of different sizes.

[0035] See also Figures 2 to 5As shown, an annular stop 311 is fixed to the inner peripheral wall of the swing port 310. The upper surface of the stop 311 is lower than the table 300a, and there is no structure on the processing table 300 that protrudes from the table 300a. Given the diameter of the wafer to be etched is D0, the inner diameter D1 of the swing port 310 is greater than or equal to D0, and the inner diameter D2 of the stop 311 is less than D0. Furthermore, D1 should be as close to D0 as possible, and the difference between D2 and D0 should not be too large, so that the wafer can be embedded in the swing port 310 as shape-fitting as possible and stably supported by the limit table 311. At the same time, the limit table 311 only supports the wafer within a small width range of the circumferential edge, which will not affect the normal etching of the lower surface of the wafer. When the wafer is placed in the swing port 310, the swing port 310 can be closed as tightly as possible to prevent the acid mist below the swing port 310 from escaping to the top of the wafer and contaminating the upper surface of the wafer that is not to be etched. Figure 5 As shown, the distance H between the upper surface of the limiting platform 311 and the table 300a is exactly equal to the thickness of the wafer to be etched. In this way, when the wafer is placed in the swing port 310, the upper surface of the wafer is flush with the table 300a, that is, the upper surface of all wafers is in the same horizontal plane with the table 300a.

[0036] See also Figures 3 to 6 As shown, in this embodiment, the shielding cover 400 is mounted on the mounting table 200 so as to be rotatable relative to the mounting table 200 about a rotational centerline X. The rotational centerline X extends along the width of the processing table 300 and is located on one side of the mounting slot 210. The shielding cover 400 is positioned entirely above the processing table 300 in the height direction. The shielding cover 400 specifically adopts a relatively thick and hollow structure. A baffle 410 is fixed to the side of the shielding cover 400 facing the processing table 300. The side of the baffle 410 facing the processing table 300 serves as a shielding surface 400a. Multiple reinforcement structures 420 are fixed to the other side of the baffle 410 to ensure the structural stability of the shielding cover 400.

[0037] When the etching device is in use, the shielding cover 400 has an open state and a shielding state. Figures 3 to 5 In the open state shown, the shielding cover 400 rotates upward, the shielding surface 400 a is separated from the processing table 300 , and the wafer can be freely taken from the processing table 300 . Figures 6 and 7In the shielding state shown, the shielding cover 400 rotates downward and is completely fitted against the table 300a. At this time, the shielding cover 400 partially extends into the mounting groove 210, and the shielding surface 400a is lower than the circumferential side wall of the mounting groove 210. The shielding surface 400a covers all the swing openings 310, and the shielding surface 400a is fitted on the table 300a and the upper surface of all wafers. The shielding surface 400a applies slight pressure to all wafers, so that each swing opening 310 can be closed by the wafer thereon. At the same time, due to the precise design of the depth of the limit table 311, the pressure exerted by the baffle 410 is precisely controlled, and the wafer will not be damaged due to excessive pressure.

[0038] See also Figure 2 、 Figure 4 up Figure 8 、 Figure 9 As shown, the wafer in the present embodiment adopts acid mist to etch. A spray tank 320 with a sealed inner cavity 320a is fixedly provided below the processing table 300, and the inner cavity 320a of the spray tank 320 is connected with all the swinging plate ports 310. The acid mist supply device 500 is arranged as a whole below the processing table 300, including a spray line 510, a connecting line 511, a hydrogen fluoride atomizing box 520, a hydrogen fluoride stock liquid box 530, a water atomizing box 540 and a heating box 550 etc. Among them, the spray pipeline 510 is arranged in the inner cavity 320a for spraying acid mist or water mist upward; the hydrogen fluoride atomization box 520, the hydrogen fluoride liquid tank 530, the water atomization box 540, and the heating box 550 are all arranged below the spray tank 320 and the mounting platform 200, and the heating box 550 is electrically connected to the water atomization box 540; the connecting pipe 511 is used to connect the hydrogen fluoride atomization box 520, the hydrogen fluoride liquid tank 530, the water atomization box 540 and the spray pipeline 510 (the complete connecting pipe 511 is not shown in the figure; a conventional pipe connection method can be used). In addition, the spray pipeline 510 is also connected to a nitrogen supply mechanism (not shown in the figure) that provides pressurized nitrogen.

[0039] Specifically, hydrogen fluoride stock tank 530 supplies hydrogen fluoride stock solution to hydrogen fluoride atomization tank 520, which produces hydrogen fluoride atomized liquid. Simultaneously, heating tank 550 heats pure water for water atomization tank 540, which produces water mist. The water mist and hydrogen fluoride atomized liquid are pressurized and mixed with nitrogen in spray line 510 to produce diluted hydrogen fluoride acid mist, which is then sprayed upward through spray line 510 toward the lower surface of the wafer, achieving single-sided etching of the wafer.

[0040] In addition, see Figure 2As shown, the bottom of the spray tank 320 is provided with a plurality of recovery holes 321 for recovering waste liquid at intervals. The etching apparatus also includes a waste liquid recovery mechanism (not shown), which is connected to all of the recovery holes 321. The sprayed acid mist, after reacting with the wafer, drips down to the bottom of the tank and is collected by the evenly distributed recovery holes 321. It is then introduced into the waste liquid recovery mechanism for recycling.

[0041] The working principle of the wafer single-side etching equipment in this embodiment is described in detail below:

[0042] First, with the shielding cover 400 open, multiple wafers to be etched are placed into the corresponding swing openings 310, with the surfaces to be etched facing downward. After the etching equipment is started, the shielding cover 400 is flipped down to the shielding position, and the shielding surface 400a fits and covers all the wafers, also serving to fix the wafers in place.

[0043] Subsequently, the acid mist supply device 500 generates diluted hydrogen fluoride acid mist and evenly sprays it onto the lower surface of the wafer exposed in the swing port 310. During this process, the inner cavity 320a of the spray tank 320 is an environment full of acid mist, and the lower surface of each wafer can fully contact with the acid mist, so the etching efficiency is high.

[0044] After the acid mist is sprayed for a certain period of time, the single-side etching of the wafer is completed. First, the hydrogen fluoride mist box 520 and the hydrogen fluoride stock solution box 530 are closed, while the water mist box 540 continues to operate and sprays water mist for a certain period of time to clean the lower surface of the wafer. During this process, the acid mist in the inner cavity 320a is gradually diluted.

[0045] After cleaning is completed, the water atomization box 540 can be closed, and then the shielding cover 400 is opened, and the etched wafer is taken out and enters the downstream process.

[0046] The opening and closing of the above-mentioned shielding cover 400, the loading and unloading of wafers, and the operation of the acid mist supply device 500 can all be remotely controlled by the control system according to a preset program. No human intervention is required throughout the process, and safety, automation level and processing efficiency are significantly improved.

[0047] In summary, the wafer single-sided etching equipment of this embodiment can achieve an ideal wafer single-sided etching effect through a simple and automated structural design: the upper surface of the wafer that is not to be etched will not be contaminated by the acid solution at all, while the lower surface of the wafer that is to be etched can be etched efficiently and completely, resulting in high product quality and significantly reduced production operation and maintenance costs.

[0048] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wafer single-side etching device, characterized by: The etching equipment includes a processing table, a plurality of swing openings for horizontally placing wafers to be etched are provided at intervals on the processing table, and the swing openings are circular and match the shape of the wafers to be etched. The etching equipment also includes a shielding cover arranged above the processing table, a spray tank arranged below the processing table and having a closed inner cavity, and an acid mist supply device arranged below the processing table, the inner cavity of the spray tank is connected to all the swing openings, the acid mist supply device includes a spray pipeline for spraying upwards, and the spray pipeline is arranged in the spray tank. The shielding cover has a shielding surface facing the processing table, and the shielding cover has an open state and a shielding state. When the shielding cover is in the shielding state, the shielding surface covers all the swing openings, and the shielding surface is in contact with the upper surfaces of all the wafers. Wherein, a circular limiting platform is fixedly provided on the inner peripheral wall of the swing opening, the inner diameter of the swing opening is greater than or equal to the diameter of the wafer to be etched, the inner diameter of the limiting platform is smaller than the diameter of the wafer to be etched, the processing table has a table top, the limiting platform is lower than the table top, and the distance between the upper surface of the limiting platform and the table top is equal to the thickness of the wafer to be etched, when the shielding cover is in the shielding state, the shielding surface is in contact with the table top, and the wafer to be etched on each swing opening closes the swing opening; The etching equipment also includes a mounting table, a mounting groove is provided on the mounting table, the processing table is fixed on the mounting table and is located in the mounting groove, the circumferential side wall of the mounting groove is higher than the upper surface of the processing table, when the shielding cover is in the shielding state, the shielding surface is lower than the circumferential side wall of the mounting groove, and the shielding cover is at least partially located in the mounting groove.

2. The wafer single-side etching equipment according to claim 1, characterized in that: The shielding cover is arranged on the mounting platform so as to be relatively rotatable around a rotation center line.

3. The wafer single-side etching equipment according to claim 1, characterized in that: The plurality of swing openings are arranged in an array on the processing table.

4. The wafer single-side etching equipment according to claim 1, characterized in that: The acid mist supply device includes a hydrogen fluoride atomization box for providing hydrogen fluoride acid mist, a water atomization box for providing water mist, and a nitrogen supply mechanism for providing pressurized nitrogen. The hydrogen fluoride atomization box, the water atomization box, and the nitrogen supply mechanism are respectively connected to the spray pipeline.

5. The wafer single-side etching equipment according to claim 1, characterized in that: The bottom of the spray tank is provided with a plurality of recovery holes for recovering waste liquid at intervals. The etching equipment further comprises a waste liquid recovery mechanism, which is connected to all the recovery holes.

6. The wafer single-side etching equipment according to any one of claims 1 to 5, characterized in that: The etching equipment includes a shell having a closed processing space, the processing table, the shielding cover, the spray tank and the acid mist supply device are all arranged in the processing space, and the etching equipment also includes an exhaust device for discharging the gas in the processing space to the outside of the processing space, and the exhaust device includes a wind valve arranged on the shell.

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