Wet etching fixture

Abstract

The present invention belongs to the field of micro-nano processing technology, and particularly relates to a wet etching fixture, which includes a base, a top cover and a sealing mechanism. A bearing part is provided on the base for bearing the wafer to be etched. The top cover is arranged above the base. The sealing mechanism is used to prevent the etching solution from contacting the front side of the wafer facing the bearing part. The sealing mechanism, the top cover and the back side of the wafer together form a chamber for accommodating the etching solution. A spray head is arranged in the chamber, and the liquid outlet of the spray head is located above the bearing part for spraying the etching solution to etch the back side of the wafer. It has comprehensive functions and has the functions of comprehensively etching and locally etching the back side of the wafer. Comprehensive etching: Load the wafer to be etched, fill the chamber with a sufficient amount of etching solution, and comprehensively etch the back side of the wafer; Local etching: Load the wafer to be etched, spray the etching solution on a specific area of the back side of the wafer through the spray head, and perform micro-etching on a local area of the back side of the wafer.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano processing, and particularly relates to a wet etching fixture. Background Art

[0002] Micro-nano processing is the processing at the micron and nano levels, and is often applied in fields such as materials science and chip design. Generally, through photolithography technology, LIGA technology, bonding technology, packaging technology, etc., patterns are transferred onto a substrate, which is usually a silicon wafer.

[0003] In order to functionalize the chip, generally a metal film, a semiconductor film, etc. are deposited on the front side of the wafer, and a part of the wafer is selectively etched on the back side of the wafer. In the wet etching process, the etching solution often reacts with the film material on the front side of the wafer, thereby damaging the film structure on the front side of the wafer. The usual method to protect the film structure on the front side of the wafer is to spin-coat a protective glue on the front side of the wafer, but this method has high cost, poor effect, and the protective glue is not easy to remove.

[0004] The invention patent CN105405802A discloses a wet etching protection fixture, which can protect the front side of the wafer from being etched without coating the protective glue, but has a relatively single function, only has the function of comprehensively etching the back side of the wafer, and does not have the function of locally etching the back side of the wafer. Summary of the Invention

[0005] To solve the above problems, the present invention provides a wet etching fixture with more comprehensive functions, which has the functions of comprehensively etching and locally etching the back side of the wafer.

[0006] Specifically, the technical solution of the present invention is as follows:

[0007] A wet etching fixture includes a base, a top cover and a sealing mechanism. The base is provided with a carrying part for carrying the wafer to be etched. The top cover is arranged above the base. The sealing mechanism is used to prevent the etching solution from contacting the front side of the wafer facing the carrying part. The sealing mechanism, the top cover and the back side of the wafer together form a chamber for accommodating the etching solution. A spray head is arranged in the chamber, and the liquid outlet of the spray head is located above the carrying part for spraying the etching solution to etch the back side of the wafer.

[0008] Preferably, a stirrer is further arranged on the top cover, and the stirring head of the stirrer is located above the carrying part.

[0009] Preferably, the number of the spray heads is multiple. The stirring head of the stirrer is arranged at the center of the top cover, and multiple spray heads are arranged around the stirring head.

[0010] Preferably, the sealing mechanism includes a locking mechanism and a sealing ring disposed above the bearing portion. The wafer to be etched is placed between the bearing portion and the sealing ring. The inner diameter of the sealing ring is smaller than the size of the wafer to be etched. Under the locking of the locking mechanism, the top cover tightly presses the sealing ring.

[0011] Preferably, a first groove is provided on the top surface of the base. The first groove is a cylindrical structure. The sealing ring is an annular structure. The outer diameter is smaller than the diameter of the first groove. The bearing portion is a bearing piece disposed in the first groove, and the bearing piece is a circular structure.

[0012] Preferably, a buffer washer is provided below the bearing piece, and the buffer washer has the same size as the sealing ring.

[0013] Preferably, the top cover includes a cylinder. An extension portion extending radially outward is provided at the top of the cylinder. A second groove recessed upward is provided on the bottom surface of the cylinder. The diameter of the second groove is the same as the inner diameter of the sealing ring. The nozzle is disposed in the second groove. The locking mechanism includes a plurality of screws connecting the extension portion and the base.

[0014] Preferably, the top cover includes an upper cover and a lower cover. The upper cover is a disc structure and is disposed above the lower cover. The nozzle is fixed on the upper cover.

[0015] Preferably, the outer peripheral surface of the extension portion is flush with the outer peripheral surface of the base. A plurality of first screw holes are provided around the first groove on the base. A second screw hole is provided on the extension portion. The screw is screwed into the first screw hole and the second screw hole and locked to fix the top cover on the base.

[0016] Preferably, the bearing piece is made of alkali-resistant glass or steel, and the base and the top cover are made of polytetrafluoro material.

[0017] The wet etching fixture provided by the present invention has comprehensive functions and has the functions of comprehensively etching and locally etching the back surface of the wafer. Comprehensive etching: Load the wafer to be etched, load a sufficient amount of etching solution into the chamber, and comprehensively etch the back surface of the wafer; Local etching: Load the wafer to be etched, spray the etching solution on a specific area of the back surface of the wafer through the nozzle, and perform micro-etching on a local area of the back surface of the wafer. Description of the Drawings

[0018] Figure 1 It is a structural diagram of the first embodiment of the present invention;

[0019] Figure 2 It is an exploded structural diagram of the first embodiment of the present invention;

[0020] Figure 3 It is an exploded structural diagram of another perspective of the first embodiment of the present invention;

[0021] Figure 4 It is a cross-section of the first embodiment of the present invention Figure 1 ;

[0022] Figure 5 For Figure 4 an enlarged view of part A in

[0023] Figure 6 a sectional view of the first embodiment of the present invention Figure 2 ;

[0024] Figure 7 a sectional view of the top cover, stirring head and nozzle of the first embodiment of the present invention. Detailed implementation manners

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Embodiment 1:

[0027] As Figures 1 to 7 shown, a wet etching fixture includes a base 1, a top cover and a sealing mechanism. A bearing part is provided on the base 1 for bearing a wafer 3 to be etched. When loading the wafer 3, the front side of the wafer faces the bearing part and the back side of the wafer faces the top cover. The top cover is arranged above the base 1. The sealing mechanism is used to prevent the etching solution from contacting the front side of the wafer facing the bearing part. The sealing mechanism, the top cover and the back side of the wafer together form a chamber 9 for accommodating the etching solution. A nozzle 4 is arranged in the chamber. The liquid outlet of the nozzle 4 is located above the bearing part and is used to spray the etching solution to etch the back side of the wafer. As for how to supply the etching solution to the nozzle 4, those skilled in the art can choose arbitrarily. For example, a liquid storage chamber can be arranged in the upper cover 22, and a liquid injection port communicated with the liquid storage chamber can be arranged on the side of the upper cover 22. The nozzle 4 is connected to the liquid storage chamber. When local etching is required, the etching solution required for one-time etching is injected into the liquid storage chamber from the liquid injection port at one time by a conduit, and then the liquid injection port is sealed with fluororubber. The etching solution in the liquid storage chamber will be sprayed out from the liquid outlet of the nozzle 4. For the nozzles 4 that are not needed, the liquid outlets of the nozzles 4 can be sealed with fluororubber. The method of supplying the etching solution to the nozzle 4 is relatively easy for those skilled in the art to think of and implement. Therefore, the relevant structures are not shown in detail in the drawings, but only described briefly in the above text.

[0028] Full etching: Load the wafer 3 to be etched, load a sufficient amount of etching solution into the chamber, and perform full etching on the back side of the wafer; Local etching: Load the wafer 3 to be etched, spray the etching solution on a specific area of the back side of the wafer through the nozzle 4, and perform micro-etching on a local area of the back side of the wafer.

[0029] Further, a stirrer 5 is also provided on the top cover, and the stirring head of the stirrer 5 is located above the bearing part. When comprehensively etching the back surface of the wafer, the stirrer 5 can fully stir the etching solution in the chamber 9, so that the back surface of the wafer is evenly etched. In this embodiment, the driving device of the stirrer 5 is arranged outside the fixture, and the output end of the driving device passes through the top cover and is connected to the stirring head of the stirrer 5 to drive the stirring head to rotate. The stirrer adopted in the present invention is an existing stirrer and can be purchased on the market. The structure of the stirrer itself is not an improvement point of the present invention, so it is not completely shown in the drawings (neither the stirring shaft nor the driving device is shown), but only the installation position of the stirring head is schematically shown.

[0030] Further, the number of the nozzles 4 is multiple, the stirring head of the stirrer 5 is arranged at the center of the top cover, and the multiple nozzles 4 surround the stirring head and are arranged around the stirring head. The function of the nozzles 4 is to perform local micro-etching on the wafer 3, and it is preferably arranged more dispersedly, while the function of the stirring head is to stir the etching solution in the fixture evenly, and it is preferably arranged at the center of the fixture.

[0031] Further, the sealing mechanism includes a locking mechanism and a sealing ring 61 arranged above the bearing part. The wafer 3 to be etched is placed between the bearing part and the sealing ring 61. The inner diameter of the sealing ring 61 is slightly smaller than the size of the wafer 3 to be etched to ensure that the top cover does not directly contact the wafer 3. Under the locking of the locking mechanism, the top cover tightly presses the sealing ring 61. Specifically, the sealing ring 61 can be made of fluororubber or chlororubber resistant to alkali solution corrosion. In this embodiment, the outer diameter of the sealing ring 61 is slightly larger than the size of the wafer 3 to be etched to ensure that the sealing ring 61 can completely protect the edge of the wafer 3 and prevent the edge of the wafer 3 from directly contacting the top cover.

[0032] Using the sealing ring 61 and the locking mechanism to achieve sealing, preventing the etching solution from contacting the side of the wafer 3 facing the bearing part, has a simple structure and convenient operation. In other embodiments, other existing sealing mechanisms with other structures can also be used to achieve sealing.

[0033] Further, a first groove 11 is formed by the downward depression of the top surface of the base 1. The first groove 11 is a cylindrical structure, the sealing ring 61 is an annular structure, and the outer diameter is slightly smaller than the diameter of the first groove 11 to facilitate the loading and removal of the sealing ring 61. The bearing part is a bearing piece 12 arranged in the first groove 11. The bearing piece 12 is a circular structure, and the outer diameter is the same as that of the wafer 3 to be etched; if the size of the bearing piece 12 is too small, the wafer 3 is easily damaged when loading the wafer 3, and if the size of the bearing piece 12 is too large, it is not convenient to take out the bearing piece 12 from the first groove 11. In this embodiment, the base 1 is a cylindrical structure, making the fixture structure compact.

[0034] Further, the carrier sheet 12 is made of alkali-resistant glass or steel, and the base 1 and the top cover are made of polytetrafluoroethylene material, which has low cost and is easy to manufacture.

[0035] Further, a buffer washer 62 is provided below the carrier sheet 12. The buffer washer 62 can buffer the pressure of the top cover on the wafer 3. The carrier sheet 12 can protect the wafer 3 and prevent the wafer 3 from cracking. The buffer washer 62 has the same size as the sealing ring 61, so that the positions of the buffer washer 62 and the sealing ring 61 are as consistent as possible, and better buffer the pressure of the top cover on the wafer 3.

[0036] Further, as Figure 7 shown, the top cover includes a cylinder, and an extension portion extending radially outward is provided at the top of the cylinder. The bottom surface of the cylinder is recessed upward to form a second groove 21, and the diameter of the second groove 21 is consistent with the inner diameter of the sealing ring 61; if the diameter of the second groove 21 is too large, it will hinder the corrosion of the wafer 3. The nozzle 4 is provided in the second groove 21, and the locking mechanism includes a plurality of screws 71 connecting the extension portion and the base. In this embodiment, the outer diameter of the cylinder is consistent with the outer diameter of the sealing ring 61 to ensure that the cylinder does not directly contact the wafer 3.

[0037] Further, the top cover includes an upper cover 22 and a lower cover 23. The upper cover 22 is a disc structure and is provided above the lower cover 23. The nozzle 4 is fixed on the upper cover 22, which is convenient for loading the etching solution and disassembling and assembling and adjusting the nozzle 4. In other embodiments, the top cover can also adopt an integrated structure.

[0038] Further, the outer peripheral surface of the extension portion is flush with the outer peripheral surface of the base 1, making the fixture structure compact. A plurality of first screw holes 13 are provided around the first groove 11 on the base 1, and a second screw hole 24 is provided on the extension portion. The screw 71 is screwed into the first screw hole 13 and the second screw hole 24 and locked, so as to fix the top cover on the base 1 and press the sealing ring 61 by the top cover.

[0039] Usage method:

[0040] (1) Full corrosion

[0041] Place the back side of the wafer 3 to be etched face up on the carrier sheet 12, cover the lower cover 23, load a sufficient amount of etching solution, cover the upper cover 22, lock the screw 71, and start the stirrer 5 to perform full and uniform etching on the back side of the wafer.

[0042] (2) Local corrosion

[0043] Place the back side of the wafer 3 to be etched face up on the carrier sheet 12, cover the lower cover 23 and the upper cover 22, spray the etching solution on a specific area of the back side of the wafer through the nozzle 4, and perform micro-etching on a local area of the back side of the wafer.

[0044] The above are only the preferred embodiments of the present invention and do not limit the present invention. It should be pointed out that any modifications, equivalent replacements, improvements, etc. made by those skilled in the art after reading this specification shall be included within the protection scope of the present invention.

Claims

1. A wet etching fixture, characterized in that, It includes a base, a top cover and a sealing mechanism. A bearing part is provided on the base for bearing the wafer to be etched. A stirrer is also provided on the top cover, and the stirring head of the stirrer is located above the bearing part. The top cover is arranged above the base, and the sealing mechanism is used to prevent the etching solution from contacting the front side of the wafer facing the bearing part. The sealing mechanism includes a locking mechanism and a sealing ring arranged above the bearing part. The wafer to be etched is placed between the bearing part and the sealing ring. The inner diameter of the sealing ring is smaller than the size of the wafer to be etched. Under the locking of the locking mechanism, the top cover tightly presses the sealing ring. The sealing mechanism, the top cover and the back side of the wafer jointly form a chamber for accommodating the etching solution. A spray head is arranged in the chamber, and the liquid outlet of the spray head is located above the bearing part for spraying the etching solution to etch the back side of the wafer. The number of the spray heads is multiple. The stirring head of the stirrer is arranged at the center of the top cover, and the multiple spray heads surround the stirring head and are arranged around the stirring head.

2. The wet etching fixture according to claim 1, wherein, A first groove is provided on the top surface of the base. The first groove is a cylindrical structure. The sealing ring is an annular structure, and the outer diameter is smaller than the diameter of the first groove. The bearing part is a bearing piece arranged in the first groove, and the bearing piece is a circular structure.

3. The wet etching fixture according to claim 2, wherein A buffer gasket is provided below the bearing piece, and the buffer gasket has the same size as the sealing ring.

4. The wet etching fixture according to claim 2, characterized in that, The top cover includes a cylinder. An extension part extending radially outward is provided at the top of the cylinder. A second groove recessed upward is provided at the bottom surface of the cylinder. The diameter of the second groove is consistent with the inner diameter of the sealing ring. The spray head is arranged in the second groove. The locking mechanism includes multiple screws connecting the extension part and the base.

5. The wet etching fixture according to claim 4, wherein The top cover includes an upper cover and a lower cover. The upper cover is a disc structure and is arranged above the lower cover. The spray head is fixed on the upper cover.

6. The wet etching fixture according to claim 4, wherein The outer peripheral surface of the extension part is flush with the outer peripheral surface of the base. Multiple first screw holes are provided around the first groove on the base. A second screw hole is provided on the extension part. The screw is screwed into the first screw hole and the second screw hole and locked to fix the top cover on the base.

7. The wet etching fixture according to claim 2, wherein The bearing piece is made of alkali-resistant corrosion glass or steel, and the base and the top cover are made of polytetrafluoro material.

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