A conductive layer structure for a laser, its fabrication method, and the laser.

Abstract

This application provides a conductive layer structure for a laser, its fabrication method, and a laser, relating to the field of semiconductor manufacturing. The fabricated conductive layer is a stacked structure, including a first metal layer, a second metal layer, and a third metal layer. Photoresist is applied to the first metal layer, and the location is determined by the photoresist pattern obtained after development and exposure. Electroplating and evaporation processes are then performed on top of the first metal layer to obtain the second and third metal layers of the conductive layer structure. The second metal layer has a first opening, and the third metal layer covers the second metal layer. This application utilizes different processes to form the AU layer, resulting in good contact during wire bonding, reducing the welding defect rate. It also optimizes the photoresist morphology and evaporation process, significantly improving the formation quality of the metallization layer and enhancing the photoresist stripping effect.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a conductive layer structure for a laser, a method for preparing the same, and a laser. Background Technology

[0002] In microelectronic packaging and photolithography, the formation of metallization layers (such as gold (AU) layers) is crucial for wire bonding processes. The conductive layer structure on the surface of a semiconductor substrate is formed through photolithography, etching, deposition, and ion implantation. In existing technologies, the fabrication process is often complex, and it is difficult to effectively control the shape of the metal layer and the photoresist stripping effect, leading to problems during the packaging wire bonding process. For example, the metal layer (such as AU) is deposited on the substrate surface through high-temperature evaporation or sputtering, but the step coverage is poor, and uneven thickness is prone to occur under complex morphologies. If there is no gap between the photoresist and the metal layer or the sidewall morphology of the photoresist is poor, the metal layer is prone to breakage or photoresist residue during stripping, requiring multiple cleanings or rework, resulting in difficult stripping. Furthermore, metal layers (such as AU) formed by a single process are not conducive to packaging wire bonding. Summary of the Invention

[0003] The purpose of this application is to provide a conductive layer structure for a laser, a method for fabricating the same, and a laser, in order to improve the technical problems raised in the background section.

[0004] For the purposes mentioned above, this application provides the following technical solution:

[0005] The first aspect of this application provides a conductive layer structure for a laser, the conductive layer structure comprising a first metal layer, a second metal layer and a third metal layer stacked sequentially, the second metal layer and the third metal layer each having an opening structure, the cross-sectional shape of the opening structure along the direction perpendicular to the first metal layer being trapezoidal; one end of the second metal layer near the opening structure is flush with one end of the third metal layer near the opening structure; or, the end of the second metal layer near the opening structure and the end of the third metal layer near the opening structure form a notch structure.

[0006] Furthermore, when the end of the second metal layer near the opening structure is flush with the end of the third metal layer near the opening structure, the trapezoid is a regular trapezoid.

[0007] When the end of the second metal layer near the opening structure and the end of the third metal layer near the opening structure form a notch structure, the trapezoid is an inverted trapezoid.

[0008] The second aspect of this application provides a method for fabricating a conductive layer structure for a laser. The fabricated laser includes a first metal layer, a second metal layer, and a third metal layer as described in the first aspect of this application. The method includes the following steps:

[0009] A photoresist pattern is formed on the surface of the first metal layer, and the cross section of the photoresist pattern along the direction perpendicular to the surface of the first metal layer is trapezoidal;

[0010] The second metal layer is formed on top of the first metal layer based on the photoresist pattern, and the third metal layer is formed on the second metal layer.

[0011] Furthermore, the trapezoid includes an upright trapezoid and an inverted trapezoid. When the cross-section of the photoresist pattern perpendicular to the direction of the first metal layer is an upright trapezoid, the method further includes:

[0012] Step S11: Based on the second photoresist pattern, the cross section of the second photoresist pattern perpendicular to the direction of the first metal layer is a trapezoid. After forming the second metal layer above the first metal layer, the photoresist is peeled off. The second metal layer has a first opening, and the cross section of the first opening perpendicular to the direction of the first metal layer is a trapezoid.

[0013] Step S12: A first photoresist pattern is formed in the first opening, and the cross section of the first photoresist pattern perpendicular to the direction of the first metal layer is an inverted trapezoid.

[0014] Step S13: Form the third metal layer on the second metal layer based on the first photoresist pattern.

[0015] Preferably, in step S12, the height of the first photoresist pattern is greater than or equal to the sum of the heights of the second metal layer and the third metal layer.

[0016] Preferably, in step S12, the maximum width of the inverted trapezoidal cross section of the first photoresist pattern is less than the minimum width of the first opening.

[0017] Preferably, the second metal layer includes a first part and a second part, the first end of the first photoresist pattern and the end of the first part have a first distance in the horizontal direction, the second end of the first photoresist pattern and the end of the second part have a second distance in the horizontal direction, and the first distance and the second distance are equal and both are greater than 0.

[0018] Furthermore, the trapezoid includes an upright trapezoid and an inverted trapezoid. When the cross-section of the photoresist pattern perpendicular to the direction of the first metal layer is an inverted trapezoid, the method further includes:

[0019] Step S21: A second metal layer is formed on the first metal layer based on the photoresist pattern. The second metal layer has a second opening, and the cross-section of the second opening perpendicular to the direction of the first metal layer is an inverted trapezoid.

[0020] Step S22: Form the third metal layer on the second metal layer based on the photoresist pattern, and peel off the photoresist.

[0021] Preferably, in step S22, the height of the photoresist pattern is greater than or equal to the sum of the heights of the second metal layer and the third metal layer.

[0022] Preferably, in step S21, the sidewalls of the photoresist pattern are in seamless contact with the sidewalls of the second metal layer.

[0023] Preferably, in step S22, the sidewalls of the photoresist pattern have non-contact gaps with the sidewalls of the third metal layer.

[0024] Preferably, the second metal layer includes a third part and a fourth part, and the third metal layer includes a fifth part and a sixth part. The fifth part has a third distance in the horizontal direction between the end near the second opening and the top of the third part, and the sixth part has a fourth distance in the horizontal direction between the end near the second opening and the top of the fourth part. The third distance and the fourth distance are equal and both are greater than 0.

[0025] Preferably, the first metal layer is obtained by vapor deposition; the second metal layer is obtained by electroplating; and the third metal layer is obtained by vapor deposition.

[0026] A third aspect of this application provides a laser, which includes a laser conductive layer structure provided in the first aspect of this application.

[0027] The method for fabricating a conductive layer structure for a laser described above, as provided in this application, can achieve at least the following technical effects:

[0028] This application utilizes AU layers formed through different processes to ensure good contact during wire bonding, reduce the welding defect rate, effectively improve the adhesion and structural stability between different metal layers, and facilitate subsequent encapsulation and wire bonding of the conductive layer structure. Optimizing the photoresist morphology reduces the difficulty of stripping. The photoresist structure is used to prepare the conductive layer structure, thereby improving the uniformity of current distribution and conductivity, thus enhancing the electrical reliability and lifespan of the entire laser device. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic flowchart of a method for fabricating a conductive layer structure for a laser, provided in the embodiments of this application.

[0031] Figure 2 A schematic diagram illustrating the preparation method of the photoresist using a two-coating process, which is part of the embodiments of this application;

[0032] Figure 3 This is a schematic diagram illustrating the preparation method of the photoresist provided in the embodiments of this application using a single coating process.

[0033] Reference numerals: 1. First metal layer; 21. First photoresist pattern; 2. Second metal layer; 3. Third metal layer; 31. First part; 32. Second part; 33. Third part; 34. Fourth part; 35. Fifth part; 36. Sixth part; 37. Seventh part; 38. Eighth part. Detailed Implementation

[0034] The technical solutions of this application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] This application provides a method for fabricating a conductive layer structure for a laser. The AU layer formed using different processes ensures good contact during wire bonding, reducing the welding defect rate. By optimizing the photoresist morphology and evaporation process, the formation quality of the metallization layer is significantly improved. According to... Figure 1 As shown in this embodiment, a method for fabricating a conductive layer structure for a laser is provided. The fabricated conductive layer is a stacked structure, including a first metal layer 1, a second metal layer 2, and a third metal layer 3. The fabrication method includes:

[0036] Step S1: A photoresist pattern is formed on the surface of the first metal layer 1, wherein the cross section of the photoresist pattern along the direction perpendicular to the surface of the first metal layer 1 is trapezoidal;

[0037] Step S2: Based on the photoresist pattern, form the second metal layer 2 above the first metal layer 1, and form the third metal layer 3 on the second metal layer 2.

[0038] Specifically, the conductive layer structure of the laser includes a first metal layer 1, a second metal layer 2, and a third metal layer 3 sequentially fabricated along the Z-axis. The first metal layer 1, the second metal layer 2, and the third metal layer 3 are all fabricated using electroplating or vapor deposition processes. During the fabrication of this stacked structure, multiple photolithography processes using photoresist are required to construct a new circuit structure each time. Based on the chemical properties of the photoresist and the post-exposure processing method, photoresists are classified into positive photoresists and negative photoresists. The choice between positive and negative photoresists depends on the required pattern size, resolution, contrast, and specific manufacturing process requirements.

[0039] In this embodiment, the second metal layer 2 is preferably prepared by electroplating, and the third metal layer 3 is prepared by vapor deposition.

[0040] Furthermore, photoresist is applied to the first metal layer 1, and the photoresist is exposed to ultraviolet light and developed using a developing solution to form a photoresist pattern. Based on the photoresist pattern obtained after development, the electroplating area of ​​the second metal layer 2 is positioned, and an AU layer is electroplated on the first metal layer 1 using an electroplating solution (such as potassium gold cyanide system) to form the second metal layer 2. The second metal layer 2 forms a first opening based on the photoresist pattern, including a first portion 31 located on the left side of the first opening and a second portion 32 located on the right side of the first opening, with the photoresist pattern disposed inside the first opening.

[0041] Optionally, in steps S1 and S2, the photoresist coating performed before forming the third metal layer 3 includes a single coating process and a double coating process. The single coating process includes: first coating (spinning, exposure, development), electroplating, evaporation, and stripping. The double coating process includes: first coating (spinning, exposure, development), electroplating, first stripping, second coating (spinning, exposure, development), evaporation, and second stripping. In the single coating process, photoresist is stripped twice after obtaining the electroplated layer and the evaporated layer, respectively, to obtain the final conductive layer structure. In the double coating process, after forming the electroplated layer, the photoresist is not stripped directly; instead, evaporation is performed directly, and after forming the evaporated layer, photoresist is stripped once to obtain the final conductive layer structure.

[0042] Preferably, the photoresist pattern used to form the vapor-deposited metal layer is formed by negative photoresist development in a direction perpendicular to the first metal layer 1 (i.e., Figure 2 and Figure 3The photoresist pattern shown (in the Z-axis direction) has an inverted trapezoidal cross-section, creating a natural gap between the vapor-deposited metal layer and the photoresist sidewalls. This prevents metal from accumulating on top of the photoresist to form a closed capping layer, disrupting the breakage mechanism during peeling and facilitating photoresist peeling. In the first coating process, the photoresist pattern with inverted trapezoidal sidewalls is applied first; in the second coating process, the photoresist pattern with regular trapezoidal sidewalls is applied first, and the photoresist pattern with inverted trapezoidal sidewalls is applied second. The inverted trapezoidal sidewalls mean that the top side of the photoresist pattern cross-section is longer than the bottom side, and the two sidewalls are equal in length. In this embodiment, the cross-sectional shape of the photoresist pattern is centrally symmetrical.

[0043] In this embodiment, proximity exposure is preferably used to form the photoresist pattern, and the shape of the photoresist pattern is preferably an inverted trapezoid or a regular trapezoid in cross section along the Z-axis direction.

[0044] Furthermore, based on the photoresist pattern within the first opening, a third metal layer 3 (evaporated layer) is formed by physical vapor deposition above the second metal layer 2, i.e., the electroplated layer. The photoresist is then dissolved using a photoresist stripping solution. Utilizing the slit structure of the first opening, the photoresist and the evaporated metal layer above it are simultaneously detached, resulting in a composite structure retaining both the electroplated and evaporated layers, forming the final evaporated AU layer. The evaporated AU layer corresponds in position to the electroplated AU layer and shares the first opening with it. The conductive layer fabrication method of this embodiment stacks multiple different metal layers and forms the AU layer through different processes, facilitating wire bonding (electroplated AU layers are not easily used for wire bonding, thus requiring a second evaporated AU layer, which is beneficial for packaging).

[0045] It should be understood that the regular trapezoid described in this application is as follows: Figure 2 The length of the top edge of the open structure shown is less than the length of the bottom edge; the inverted trapezoid described in this application is as follows. Figure 3 The length of the bottom edge of the opening structure shown is less than the length of the top edge. The top edge and the bottom edge can be the lengths of the edges defined by the third part 33 and the fourth part 34; the bottom edge is the edge that contacts the first metal layer 1.

[0046] Example 1

[0047] like Figure 2 As shown, in the method for fabricating the conductive layer structure of the laser, when the photoresist coating performed before forming the vapor deposition layer adopts a two-coating process, the method includes the following steps:

[0048] Step S11: Form a second photoresist pattern above the first metal layer, photolithographically etch the second metal layer based on the second photoresist pattern and peel off the photoresist. The second metal layer has a first opening, and the cross-section of the first opening perpendicular to the direction of the first metal layer is a trapezoid.

[0049] Preferably, the photoresist applied in step S11 is electroplated photoresist (PR). The cross-section of the second photoresist pattern perpendicular to the direction of the first metal layer is a trapezoidal pattern, meaning the length of the top edge in the cross-section direction is less than the length of the bottom edge, and the sides are equal. The bottom angle of the second photoresist pattern is 30-60 degrees, and more preferably 45 degrees.

[0050] Step S12: A first photoresist pattern 21 is formed in the first opening, and the cross section of the first photoresist pattern 21 perpendicular to the direction of the first metal layer 1 is an inverted trapezoid.

[0051] Step S13: Form the third metal layer 3 on the second metal layer 2 based on the first photoresist pattern 21. The second metal layer 2 includes a first portion 31 and a second portion 32, and the third metal layer includes a seventh portion 37 and an eighth portion 38.

[0052] Preferably, the photoresist applied in step S12 is vapor-deposited photoresist (PR). The cross-section of the first photoresist pattern 21 along the direction perpendicular to the first metal layer is an inverted trapezoidal pattern, meaning the length of the top edge in the cross-section direction is greater than the length of the bottom edge, and the side edges are equal. The bottom angle of the first photoresist pattern 21 is 120-150 degrees, and more preferably 135 degrees.

[0053] Preferably, in step S13, the height of the first photoresist pattern 21 is greater than or equal to the sum of the heights of the second metal layer 2 and the third metal layer 3.

[0054] Preferably, in step S13, the maximum width of the inverted trapezoidal cross-section of the first photoresist pattern 21 is less than the minimum width of the first opening. Since the lithography machine has alignment offset, lithography tolerance needs to be considered. Therefore, in this embodiment, the top width of the first photoresist pattern 21 is set to be less than the top width of the first opening to meet the overlay accuracy requirements.

[0055] Preferably, the second metal layer 2 includes a first portion 31 and a second portion 32. The first end of the first photoresist pattern 21 and the end of the first portion 31 have a first distance in the horizontal direction, and the second end of the first photoresist pattern 21 and the end of the second portion 32 have a second distance in the horizontal direction. The first distance and the second distance are equal and both are greater than 0.

[0056] Specifically, in this embodiment, multiple layers of different metals are stacked and formed into an AU layer through different processes, which facilitates the encapsulation of bonding wires. Photoresist is applied through a secondary coating process, and the first photoresist pattern 21 is an inverted trapezoid. By setting the height of the first photoresist pattern 21 to be greater than the sum of the height of the electroplated layer and the height of the vapor-deposited layer, and by having non-contact gaps between the sidewalls of the first photoresist pattern 21 and both the electroplated and vapor-deposited layers, the resulting inverted trapezoidal vapor-deposited photoresist morphology can prevent metal from accumulating on top of the photoresist to form a closed capping layer, thus disrupting the breakage mechanism during peeling. Furthermore, the "quadrilateral" gap formed between the bottom of the first photoresist pattern 21 and the opening facilitates the entry of the peeling remover, thereby promoting the bottom peeling of the first photoresist pattern 21.

[0057] Example 2

[0058] like Figure 3 As shown, in the method for fabricating the conductive layer structure of the laser, when the photoresist coating performed before forming the vapor deposition layer is a one-time coating process, the method includes the following steps:

[0059] Step S21: A second metal layer is formed on the first metal layer based on the photoresist pattern. The second metal layer has a second opening, and the cross-section of the second opening perpendicular to the direction of the first metal layer is an inverted trapezoid.

[0060] Preferably, the photoresist applied in step S21 is an electroplated photoresist (PR), and the photoresist pattern has an inverted trapezoidal cross-section perpendicular to the first metal layer, meaning the top edge length is greater than the bottom edge length, and the sides are equal. The base angle of the inverted trapezoidal photoresist pattern is 120-150 degrees, and more preferably 135 degrees.

[0061] Step S22: Form the third metal layer on the second metal layer based on the photoresist pattern, and peel off the photoresist.

[0062] Specifically, in step S22, positioning is performed based on the photoresist pattern, and an electroplating process is performed above the first metal layer 1 to obtain a second metal layer, i.e., an electroplated layer. The electroplated layer includes a third portion 33 and a fourth portion 34 located above the first metal layer 1, respectively, with a second opening of an inverted trapezoidal cross-section formed between the third portion 33 and the fourth portion 34. Then, without stripping the photoresist with the inverted trapezoidal pattern, a vapor deposition process is performed directly above the electroplated layer and the second opening. After vapor deposition, the photoresist pattern and the metal deposits above it are removed by a stripping process to obtain a vapor-deposited layer. The vapor-deposited layer includes a fifth portion 35 located above the third portion 33 and a sixth portion 36 located above the fourth portion 34.

[0063] Preferably, the height of the photoresist pattern is greater than or equal to the sum of the heights of the second metal layer 2 and the third metal layer 3.

[0064] Preferably, in step S22, the sidewalls of the photoresist pattern are in seamless contact with the sidewalls of the second metal layer 2.

[0065] Preferably, in step S22, the second metal layer 2 includes a third portion 33 and a fourth portion 34, and the third metal layer 3 includes a fifth portion 35 and a sixth portion 36. The fifth portion 35 has a third distance in the horizontal direction between its end near the second opening and the top of the third portion 33, and the sixth portion 36 has a fourth distance in the horizontal direction between its end near the second opening and the top of the fourth portion 34. The third distance and the fourth distance are equal and both are greater than 0.

[0066] Preferably, the end of the fifth part 35 near the second opening is recessed relative to the end of the third part 33 near the second opening in a direction away from the second opening, forming a first stepped structure; the end of the sixth part 36 near the second opening is recessed relative to the end of the fourth part 34 near the second opening in a direction away from the second opening, forming a second stepped structure.

[0067] Specifically, this embodiment employs a single photolithography and single stripping process, reducing the number of steps and the amount of photoresist, developer, and stripping solution used. By setting the cross-section of the photoresist pattern after the first photoresist coating and development to an inverted trapezoidal shape, and ensuring seamless contact between the inverted trapezoidal photoresist pattern and the sidewalls of the third part 33 and the fourth part 34 on both sides, the photoresist is not removed at the end of the electroplating process, and the photoresist forming the electroplated layer is used as the photolithography image for the next evaporation process. In this embodiment, no gap needs to be reserved between the inverted trapezoidal photoresist pattern and the second opening. Combined with the "single photolithography, single stripping" fabrication process and the inverted trapezoidal shape of the photoresist described in this embodiment, the formed top evaporation layer can directly match the size of the second opening and form a stepped structure with the electroplated layer. The overlay error approaches zero, improving the density and performance of the fabricated laser chip.

[0068] In this embodiment, preferably, the relationship between the evaporation angle α of the evaporation process and the sidewall angle θ of the photoresist pattern during the formation of the evaporation layer is as follows: ,like Figure 3 As shown.

[0069] Since the height of the inverted trapezoidal photoresist pattern is greater than the sum of the heights of the electroplated layer and the vapor-deposited layer, the fifth part 35 and the third part 33 form a stepped structure, and the sixth part 36 and the fourth part 34 form a stepped structure. When the vapor-deposited metal is deposited on the sidewall of the electroplated layer, it will form a natural fracture point, so that there are gaps between the inverted trapezoidal photoresist pattern and the fifth part 35 and the sixth part 36 on its left and right sides, which facilitates the removal of the photoresist. At the same time, in the conductive layer structure formed after removal, the vapor-deposited layer also reduces the amount of metal AU used, thus reducing costs.

[0070] This embodiment also provides a laser conductive layer structure, which is fabricated based on the laser conductive layer structure fabrication method described above in this embodiment. Since the principle behind solving the problem of a laser conductive layer structure is similar to that of a laser conductive layer structure fabrication method, the implementation of a laser conductive layer structure can refer to the implementation of a laser conductive layer structure fabrication method; repeated details will not be elaborated further. Figure 2 and Figure 3 As shown, the conductive layer structure of the laser includes a first metal layer 1, a second metal layer 2, and a third metal layer 3 stacked sequentially. The second metal layer 2 and the third metal layer 3 each have an opening structure, and the cross-sectional shape of the opening structure along the direction perpendicular to the first metal layer 1 is trapezoidal. The end of the second metal layer 2 near the opening structure is flush with the end of the third metal layer 3 near the opening structure; or, the end of the second metal layer 2 near the opening structure and the end of the third metal layer 3 near the opening structure form a notch structure.

[0071] Furthermore, when the end of the second metal layer 2 near the opening structure is flush with the end of the third metal layer 3 near the opening structure, the trapezoid is a regular trapezoid.

[0072] When the end of the second metal layer 2 near the opening structure and the end of the third metal layer 3 near the opening structure form a notch structure, the trapezoid is an inverted trapezoid.

[0073] This embodiment also provides a laser, including the laser conductive layer structure described above.

[0074] The embodiments of the present invention achieve the following technical effects:

[0075] 1. In this embodiment, multiple layers of different metals are stacked and different processes are used to form the conductive AU layer of the laser, which facilitates encapsulation and wire bonding;

[0076] 2. This embodiment provides a secondary coating process for photoresist. By changing the cross-section of the photoresist to a regular trapezoid or an inverted trapezoid, and setting the height of the photoresist pattern to be greater than the sum of the height of the electroplated layer and the height of the vapor-deposited layer, a non-contact gap exists between the photoresist pattern and the vapor-deposited layer. The inverted trapezoidal vapor-deposited photoresist morphology can prevent metal from accumulating on top of the photoresist to form a closed cover layer, thereby disrupting the breakage mechanism during peeling and facilitating the peeling of the photoresist.

[0077] 3. This embodiment provides a one-time photoresist coating process. By not removing the third photoresist at the end of the electroplating process, the electroplated photoresist is used as the photolithography image for the next evaporation process, thereby achieving one-time photolithography and one-time stripping, reducing the process flow and the amount of photoresist, developer, stripping solution and precious metals used.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method of fabricating a laser conductive layer structure, the method comprising: The method comprises: ​ forming a second photoresist pattern on the surface of the first metal layer, the second photoresist pattern being a right trapezoid in cross section perpendicular to the surface of the first metal layer; based on the second photoresist pattern, stripping the second photoresist pattern after photoetching a second metal layer above the first metal layer, the second metal layer having a first opening, the first opening being a right trapezoid in cross section perpendicular to the first metal layer; forming a first photoresist pattern in the first opening, the first photoresist pattern being an inverted trapezoid in cross section perpendicular to the first metal layer, and based on the first photoresist pattern, photoetching a third metal layer on the second metal layer, the side wall of the first photoresist pattern having a non-contact gap with the second metal layer and the third metal layer, and the end of the second metal layer close to the first opening being flush with the end of the third metal layer close to the first opening; stripping the first photoresist pattern.

2. The method of claim 1, wherein the laser conductive layer structure is prepared by a process comprising: The height of the first photoresist pattern is greater than or equal to the sum of the heights of the second metal layer and the third metal layer. ​ And / or, the maximum width of the inverted trapezoidal cross section of the first photoresist pattern is less than the minimum width of the first opening.

3. The method of claim 2, wherein the laser conductive layer structure is prepared by a process comprising: The second metal layer comprises a first part and a second part, the first end of the first photoresist pattern and the end of the first part have a first spacing in the horizontal direction, the second end of the first photoresist pattern and the end of the second part have a second spacing in the horizontal direction, and the first spacing and the second spacing are equal and greater than 0. ​ 4. The method of claim 1 to 3, wherein The method further comprises: obtaining the first metal layer based on an evaporation process; obtaining the second metal layer based on an electroplating process; obtaining the third metal layer based on an evaporation process.

Images