Secondary photoetching patterned metal electroplating process method

Abstract

The invention relates to the technical field of semiconductor lasers, in particular to a secondary photoetching graphical metal electroplating process method, which comprises the following steps of: taking a wafer after front metal ohmic contact, uniformly coating photoresist for the first time, and pre-baking for the first time; performing primary exposure on the photoresist, and performing primary post-baking; carrying out primary development to obtain a primary reserved photoresist; a Ti-Ag metal thin layer is formed through sputtering; secondary photoresist homogenizing and secondary pre-baking are carried out; carrying out secondary exposure and secondary post-baking; performing secondary development to obtain a secondary reserved photoresist, the size of the secondary reserved photoresist being greater than the size of the primary reserved photoresist; electroplating an Au metal layer; stripping the photoresist layer to obtain a patterned Ti-Ag-Ag metal layer; the invention provides a process method capable of effectively improving the thickness uniformity of electroplated metal and reducing the process difficulty, the process method is not limited by a metal layer region and an insulating layer region on the surface of a wafer, the electroplated thick metal can uniformly cover each region, and the uniformity can reach 8%.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor lasers, and in particular relates to a secondary photolithography patterned metal electroplating process method. Background Art

[0002] In the field of semiconductor lasers, the wafer metal electrode preparation process, especially the coplanar P / N gold ohmic contact, needs to be selectively covered with thick gold (i.e., it needs to be patterned). At present, large-area dense and uniform gold conductive layers are mainly prepared by electron beam evaporation or magnetron sputtering. Since this method is expensive and not suitable for thick gold processes, the use of a lower-cost electroplating process for thick metal preparation is more conducive to commercial development. In addition, in order to obtain patterned metal, the current processing technology uses the metal LIFT OFF process, i.e., metal photoresist stripping technology.

[0003] In the thick gold metal electroplating process, there are two current distribution modes: mode 1, substrate conduction mode in the non-insulating layer covered area; mode 2, surface patterned metal conductive bridge. The one-time photolithography patterning direct electroplating method is suitable for the preparation of high-power strip semiconductor laser electrodes, that is, the current distribution of mode 2 is the main mode. For the coplanar electrode situation where the electroplating process is mainly the substrate conduction mode, the electroplating thickness uniformity is poor due to the uneven current distribution in the P / N metal area, and metal patterning cannot be achieved in the electrically insulating area. If the one-time photolithography patterning growth seed thin gold indirect electroplating method is adopted, the electroplating process is a thin layer of metal conduction mode (forming a surface metal bridge), which can effectively improve the electroplating uniformity of the P / N metal area. However, since the surface and side walls of the photoresist are covered by a thick electroplated metal layer, the stripping solution cannot completely dissolve the photoresist, making it difficult to achieve normal stripping.

[0004] In the preparation process of semiconductor laser chip electrodes, the electroplating process, which is mainly a substrate conductive method, is difficult to prepare thick metal with high uniformity due to the uneven current distribution. At the same time, the thickness of the patterned electroplated metal layer needs to reach more than 3μm. The thickness of the negative photoresist used for the stripping process in the mass production process is usually in the range of 2~10μm. The LIFT OFF process requires the ratio of photoresist thickness to stripped metal to be greater than 3:1, but too thick photoresist will affect the resolution and is not suitable for stripping of particularly thick metals. Therefore, the difficulty of stripping must be considered in the process preparation process. Summary of the invention

[0005] In view of this, the present invention aims to provide a secondary photolithography patterning metal electroplating process method which can effectively improve the uniformity of electroplated metal thickness and reduce the difficulty of LIFT OFF process (metal lift-off technology).

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows: A secondary photolithography patterning metal electroplating process method, the secondary photolithography patterning metal electroplating process method comprising the steps of: S1. A photoresist coating: Select a wafer after the front metal ohmic contact, coat the surface of the wafer with a photoresist, and perform a pre-bake; S2. Photoresist exposure once: Under the shielding of the patterned photoresist, the photoresist is exposed once and post-baked once; S3. A photoresist development: The wafer is developed once after a post-bake to remove the unexposed portion of the photoresist, retaining the photoresist above the front pattern area of ​​the wafer to obtain a retained photoresist; S4. Deposition of a thin metal layer: forming a Ti-Ag metal thin layer on the surface of the wafer; S5. Secondary photoresist coating: secondary photoresist coating on the wafer surface after forming the Ti-Ag metal thin layer, and secondary pre-baking; S6. Secondary photoresist exposure: Under the shielding of the patterned photoresist, the photoresist is subjected to secondary exposure and secondary post-baking; S7. Secondary photoresist development: performing secondary development on the wafer after the secondary post-bake, removing the unexposed portion of the photoresist, retaining the photoresist above the front pattern area of ​​the wafer, and obtaining a secondary retained photoresist, wherein the size of the secondary retained photoresist is larger than the size of the primary retained photoresist; S8. Deposition of a thick metal layer: electroplating an Au metal layer on the front side of the wafer; S9. Wet stripping: stripping the photoresist above the graphic area on the front side of the wafer and the Ti-Ag metal thin layer on the photoresist to obtain a graphic Ti-Ag-Ag metal layer on the front side of the wafer.

[0007] Furthermore, the photoresist is a negative photoresist.

[0008] Furthermore, the thickness of the negative photoresist of the first uniform photoresist is 5.5±0.5 um, the temperature of the first pre-bake is 120±2° C., and the temperature of the first post-bake is 120±2° C.

[0009] Furthermore, the thickness of the negative photoresist of the secondary uniform photoresist is 3±0.5 um, the temperature of the secondary pre-bake is 120±2° C., and the temperature of the secondary post-bake is 120±2° C.

[0010] Furthermore, the Ti—Ag metal thin layer is formed by evaporation on the surface of the wafer by using a magnetron evaporation device.

[0011] Furthermore, the thickness of the Ti-Ag metal thin layer is 100±5nm; the Ti-Ag metal thin layer includes a superimposed Ti layer and an Ag layer; the thickness of the Ti layer is 10±1nm, and the thickness of the Ag layer is 90±5nm.

[0012] Furthermore, the thickness of the Au metal layer is 4000nm±300nm.

[0013] Further, using a gold electroplating device, electroplating an Au metal layer on the front side of the wafer; The electroplating rate of the electroplating process is 100 nm / min, the temperature of the electroplating process is 60±1° C., the current of the electroplating process is 0.24±0.2A, and the time of the electroplating process is 40 min.

[0014] Furthermore, the size of the secondary retained photoresist is greater than that of the primary retained photoresist by more than 5 μm.

[0015] Further, the photoresist above the front pattern area of ​​the wafer and the Ti-Ag metal thin layer on the photoresist are stripped by immersing in a stripping solution and washing under high pressure; The stripping liquid is N-methylpyrrolidone, and the pressure of the high-pressure washing is 80 Kpa.

[0016] Compared with the prior art, the invention can achieve the following beneficial effects: The invention provides a secondary photolithography patterning metal electroplating process method, which improves the uniformity of electroplated metal thickness and reduces the difficulty of lift-off process by changing the metal conduction mode and the metal coating form of photoresist in the electroplating process; specifically, for a wafer after front metal ohmic contact, firstly, after a primary photolithography, a seed thin gold is grown by magnetron sputtering to form a metal conductive bridge on the wafer surface, and the substrate conduction mode in the electroplating process is changed to the surface metal bridge conduction mode, which can improve the uniformity of electroplated metal thickness; secondly, secondary photolithography patterning is performed to form a coating on the surface and side walls of the photoresist retained by the primary photolithography, and then electroplating is performed, in which the surface and side walls of the photoresist retained by the secondary photolithography will not form a metal coating, and the difficulty of metal stripping process can be greatly reduced.

[0017] The process method of the present invention is used for patterning, which is not limited by the metal layer area and the insulating layer area on the surface of the wafer. The electroplated thick metal can evenly cover the metal layer area and the insulating layer area, and the thickness uniformity of the electroplated thick metal can reach 8%. However, the technical solutions in the prior art cannot perform electroplating in the insulating layer area, and it is difficult to ensure the overall uniformity of the electroplated metal thickness. Moreover, compared with the traditional electron beam evaporation and magnetron sputtering gold plating methods, the production cost is low, the efficiency is high, and the stripping process is easy. The process preparation process has a higher fault tolerance rate, which can improve the product yield and ensure the stability of the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 A schematic diagram of the wafer structure after the front metal ohmic contact is created in an embodiment of the present invention; Figure 2 This is a schematic diagram of the wafer structure after one photolithography and coating in an embodiment of the present invention; Figure 3 A schematic diagram of a wafer structure after one photolithography development in an embodiment of the present invention; Figure 4 A schematic diagram of a wafer structure after a thin metal layer is deposited in an embodiment of the present invention; Figure 5 This is a schematic diagram of the wafer structure after secondary photolithography and coating in an embodiment of the present invention; Figure 6 A schematic diagram of the wafer structure after secondary photolithography development in an embodiment of the present invention; Figure 7 A schematic diagram of a wafer structure after a thick metal layer is deposited in an embodiment of the present invention; Figure 8 The schematic diagram of the wafer structure after wet stripping in the embodiment of the present invention is shown.

[0019] Description of reference numerals: 01. Wafer that needs to be electroplated with a metal layer; 02. Electrical insulation layer on the wafer; 03. Ohmic contact layer electrode on the wafer; 04. Photoresist for the first photolithography process; 05. Ti-Ag metal thin layer; 06. Photoresist for the second photolithography process; 07. Au metal layer. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0021] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0023] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0024] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0025] like Figures 1 to 8 As shown, a secondary photolithography patterning metal electroplating process method, the secondary photolithography patterning metal electroplating process method comprises the steps of: S1. First photoresist coating: select a wafer after the front metal ohmic contact, coat the surface of the wafer with photoresist, and perform a pre-baking; the photoresist is a negative photoresist; by using a negative photoresist, it is easier to form an inverted trapezoidal morphology in the photolithography process, and it is also easier to peel off the metal layer after deposition; the thickness of the negative photoresist of the first photoresist coating is 5.5±0.5um, and the temperature of the first pre-baking is 120±2℃; the thickness of the negative photoresist of the first photoresist coating can better fill the etched grooves on the wafer surface, and at the same time, it can better ensure the thickness ratio of the photoresist and the stripped metal (Ti-Ag); S2. Photoresist exposure once: Under the shielding of the patterned photoresist, the photoresist is exposed once and post-baked once; the post-baking temperature is 120±2°C; S3. A photoresist development: The wafer is developed once after a post-bake to remove the unexposed portion of the photoresist, retaining the photoresist above the front pattern area of ​​the wafer to obtain a patterned photoresist; S4. Thin metal layer deposition: by using a magnetron evaporation device, evaporating and sputtering on the surface of the above wafer to form the Ti-Ag metal thin layer, the Ti-Ag metal thin layer completely covers the primary retained photoresist to form a metal conductive bridge; the thickness of the Ti-Ag metal thin layer is 100±5nm; the Ti-Ag metal thin layer includes a superimposed Ti layer and an Ag layer; the thickness of the Ti layer is 10±1nm, and the thickness of the Ag layer is 90±5nm; S5. Secondary photoresist coating: After forming the Ti-Ag metal thin layer, the wafer surface is subjected to secondary photoresist coating and secondary pre-baking; the photoresist is a negative photoresist; the thickness of the negative photoresist of the secondary photoresist coating is 3±0.5um, and the temperature of the secondary pre-baking is 120±2°C; the thickness of the negative photoresist of the secondary photoresist coating is 3±0.5um, which is smaller than the thickness of the negative photoresist of the primary photoresist coating. The primary photoresist coating makes it easier to achieve small-size graphics; S6. Secondary photoresist exposure: Under the shielding of the patterned photoresist, the photoresist is subjected to secondary exposure and secondary post-baking; the temperature of the secondary post-baking is 120±2°C; S7. Secondary photoresist development: performing secondary development on the wafer after the secondary post-bake, removing the photoresist of the unexposed part, retaining the photoresist above the front pattern area of ​​the wafer, and obtaining a secondary retained photoresist, wherein the size of the secondary retained photoresist is larger than the size of the primary retained photoresist; the size of the secondary retained photoresist is larger than the size of the primary retained photoresist by more than 5 μm, that is, the edge is expanded by more than 5 μm, which can effectively prevent the surface and side wall of the primary retained photoresist from being coated by a thick electroplated metal layer, and avoid the stripping solution from being unable to completely dissolve the photoresist, making it difficult to achieve normal stripping; S8. Deposition of thick metal layer: using electroplating gold equipment, electroplating Au metal layer on the front side of the wafer; the electroplating rate of the electroplating process is 100 nm / min, the temperature of the electroplating process is 60±1°C, and the time of the electroplating process is 40min; the thickness of the Au metal layer is 4000nm±300nm; the electroplating process realizes electroplating gold deposition in the non-photoresist area (i.e., the graphic area) through the conductive bridge formed by the Ti-Ag metal thin layer; S9. Wet stripping: stripping the photoresist above the front graphic area of ​​the wafer and the Ti-Ag metal thin layer on the photoresist by immersing in a stripping solution and washing with high pressure; stripping the photoresist above the front graphic area of ​​the wafer includes primary retained photoresist and secondary retained photoresist; the stripping solution is N-methylpyrrolidone, and the pressure of the high-pressure washing is 80Kpa. Specifically, a fully automatic degumming and stripping machine can be used for stripping, and by stripping the photoresist above the front graphic area of ​​the wafer and the Ti-Ag metal thin layer on the photoresist, a patterned Ti-Ag-Ag metal layer is obtained on the front side of the wafer.

[0026] The embodiment of the present invention proposes a secondary photolithography patterning metal electroplating process method, which improves the uniformity of the electroplated metal thickness and reduces the difficulty of the LIFT OFF process by changing the metal conduction mode and the metal coating form of the photoresist in the electroplating process; specifically, for a wafer after the front metal ohmic contact, firstly, after a photolithography, a seed thin gold is grown by magnetron sputtering to form a metal conductive bridge on the wafer surface, and the substrate conduction mode in the electroplating process is changed to the surface metal bridge conduction mode, which can improve the uniformity of the electroplated metal thickness; secondly, a secondary photolithography patterning is performed to form a coating on the photoresist surface and side walls retained by the primary photolithography, and then electroplating is performed. In this process, the photoresist surface and side walls retained by the secondary photolithography will not form a metal coating, which can greatly reduce the difficulty of the metal stripping process.

[0027] The process method of the present invention is used for patterning without being restricted by the metal layer area and the insulating layer area on the surface of the wafer. The electroplated thick metal can evenly cover the metal layer area and the insulating layer area, and the thickness uniformity of the electroplated thick metal can reach 8%, while the technical solutions in the prior art cannot perform electroplating in the insulating layer area, and it is difficult to ensure the overall uniformity of the electroplated metal thickness; moreover, compared with traditional electron beam evaporation and magnetron sputtering gold plating methods, the production cost is low and the efficiency is high, and the stripping process is less difficult, the process preparation process has a higher fault tolerance rate, which can improve the product yield and ensure the stability of the process.

[0028] The following is a further detailed description in conjunction with specific embodiments and drawings.

[0029] Example like Figures 1 to 8 As shown, the embodiment provides a secondary photolithography patterning metal electroplating process method, and the secondary photolithography patterning metal electroplating process method includes the steps of: S1. One-time photoresist coating: Figure 1As shown, a wafer 01 to be subjected to electroplating metal layer deposition is selected. The wafer is a wafer after metal ohmic contact on the front side, and is also a wafer after epitaxial growth, photolithography, etching, and insulating film deposition. The wafer 01 to be subjected to electroplating metal layer deposition includes an electrical insulating layer 02 on the wafer and an ohmic contact layer electrode 03 on the wafer. A negative photoresist is uniformly applied on the surface of the wafer 01 to be subjected to electroplating metal layer deposition, and a pre-bake is performed. Specifically, Figure 2 As shown, the surface of the wafer 01 to be electroplated with a metal layer also includes a photolithography process photoresist 04; the thickness of the negative photoresist of the first uniform photoresist is 5.5±0.5um, and the temperature of the first pre-bake is 120±2°C; S2. Photoresist exposure: Under the shielding of the patterned photoresist, a uniform negative photoresist is exposed once and a post-bake is performed; the post-bake temperature is 120±2°C; S3. Primary photoresist development: developing with a developer, specifically developing the wafer after a post-bake with a developer, removing the unexposed portion of the photoresist, retaining the photoresist above the front pattern area of ​​the wafer, and obtaining a retained photoresist, specifically as follows Figure 3 As shown, it can be seen that a portion of the photoresist 04 is removed and a portion is retained in the first photolithography process; S4. Deposition of thin metal layers: Figure 4 As shown, a Ti-Ag metal thin layer 05 is formed by evaporating on the surface of the wafer by using a magnetron evaporation device, wherein the thickness of Ti in the Ti-Ag metal thin layer 05 is 10±1nm, and the thickness of Ag is 90±5nm; S5. Secondary photoresist coating: Figure 5 As shown, a secondary photoresist is uniformly coated on the surface of the wafer, the surface of the wafer includes a secondary photolithography process photoresist 06, the secondary photolithography process photoresist 06 is a negative photoresist, and the thickness is 3±0.5um; a secondary pre-bake is performed, and the temperature of the secondary pre-bake is 120±2°C; S6. Secondary photoresist exposure: Under the shielding of the patterned photoresist, the photoresist is subjected to secondary exposure and secondary post-baking, and the secondary post-baking temperature is 120±2°C; S7. Secondary photoresist development: Perform secondary development on the wafer after the secondary post-baking to remove the photoresist in the unexposed part and retain the photoresist above the front pattern area of ​​the wafer to obtain a secondary retained photoresist; specifically, Figure 6 As shown, it can be seen that the photoresist 06 of the secondary photolithography process has a portion removed and a portion retained, and the size of the secondary retained photoresist is larger than the size of the primary retained photoresist; S8. Thick metal layer deposition: Figure 7As shown, a thick Au metal layer 07 is electroplated on the front side of the wafer using a gold electroplating device; the electroplating rate of the electroplating process is 100 nm / min, the temperature of the electroplating process is 60±1°C, and the electroplating process time is 40min to electroplate the Au metal layer on the front side of the wafer; the thickness of the Au metal layer 07 obtained by electroplating is 4000nm±300nm; S9. Wet stripping: Figure 8 As shown, the photoresist above the wafer front graphic area and the Ti-Ag metal thin layer 04 on the photoresist are stripped by stripping liquid immersion and high-pressure washing; specifically, the stripped photoresist includes the primary photolithography process photoresist 04 and the secondary photolithography process photoresist 06 left behind; the stripping liquid is N-methylpyrrolidone, and the pressure of the high-pressure washing is 80Kpa, and a patterned Ti-Ag-Ag metal layer is obtained on the front side of the wafer; the thickness of the Ti-Ag-Ag metal layer in the upper, middle, lower, left and right areas of the wafer after stripping is tested by a step meter measuring device, and the final Ti-Ag-Ag metal layer is not limited by the metal layer area and the insulating layer area on the wafer surface, and can evenly cover the metal layer area and the insulating layer area, with a thickness uniformity of 8%.

[0030] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0031] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A secondary photolithography patterning metal electroplating process method, characterized in that: The secondary photolithography patterning metal electroplating process method comprises the following steps: S1. A photoresist coating: Select a wafer after the front metal ohmic contact, coat the surface of the wafer with a photoresist, and perform a pre-bake; S2. Photoresist exposure once: Under the shielding of the patterned photoresist, the photoresist is exposed once and post-baked once; S3. A photoresist development: The wafer is developed once after a post-bake to remove the unexposed portion of the photoresist, retaining the photoresist above the front pattern area of ​​the wafer to obtain a retained photoresist; S4. Deposition of a thin metal layer: forming a Ti-Ag metal thin layer on the surface of the wafer; S5. Secondary photoresist coating: secondary photoresist coating on the wafer surface after forming the Ti-Ag metal thin layer, and secondary pre-baking; S6. Secondary photoresist exposure: Under the shielding of the patterned photoresist, the photoresist is subjected to secondary exposure and secondary post-baking; S7. Secondary photoresist development: performing secondary development on the wafer after the secondary post-bake, removing the unexposed portion of the photoresist, retaining the photoresist above the front pattern area of ​​the wafer, and obtaining a secondary retained photoresist, wherein the size of the secondary retained photoresist is larger than the size of the primary retained photoresist; S8. Deposition of a thick metal layer: electroplating an Au metal layer on the front side of the wafer; S9. Wet stripping: stripping the photoresist above the graphic area on the front side of the wafer and the Ti-Ag metal thin layer on the photoresist to obtain a graphic Ti-Ag-Ag metal layer on the front side of the wafer.

2. The secondary photolithography patterning metal electroplating process according to claim 1, characterized in that: The photoresist is a negative photoresist.

3. The secondary photolithography patterning metal electroplating process according to claim 2, characterized in that: The thickness of the negative photoresist of the first uniform photoresist is 5.5±0.5um, the temperature of the first pre-bake is 120±2°C, and the temperature of the first post-bake is 120±2°C.

4. The secondary photolithography patterning metal electroplating process according to claim 2, characterized in that: The thickness of the negative photoresist of the secondary uniform photoresist is 3±0.5 um, the temperature of the secondary pre-bake is 120±2° C., and the temperature of the secondary post-bake is 120±2° C.

5. The secondary photolithography patterning metal electroplating process according to claim 1, characterized in that: The Ti—Ag metal thin layer is formed by evaporation on the surface of the wafer by using a magnetron evaporation device.

6. The secondary photolithography patterning metal electroplating process according to claim 1, characterized in that: The thickness of the Ti-Ag metal thin layer is 100±5nm; the Ti-Ag metal thin layer includes a superimposed Ti layer and an Ag layer; the thickness of the Ti layer is 10±1nm, and the thickness of the Ag layer is 90±5nm.

7. The secondary photolithography patterning metal electroplating process according to claim 1, characterized in that: The thickness of the Au metal layer is 4000nm±300nm.

8. The secondary photolithography patterning metal electroplating process according to claim 1, characterized in that: Using a gold electroplating device to electroplate an Au metal layer on the front side of the wafer; The electroplating rate of the electroplating process is 100 nm / min, the temperature of the electroplating process is 60±1° C., the current of the electroplating process is 0.24±0.2A, and the time of the electroplating process is 40 min.

9. The secondary photolithography patterning metal electroplating process according to claim 1, characterized in that: The size of the secondary retained photoresist is greater than that of the primary retained photoresist by more than 5 μm.

10. The secondary photolithography patterning metal electroplating process according to claim 1, characterized in that: The photoresist on the front pattern area of ​​the wafer and the Ti-Ag metal thin layer on the photoresist are stripped by stripping liquid immersion and high-pressure washing; The stripping liquid is N-methylpyrrolidone, and the pressure of the high-pressure washing is 80 Kpa.

Images