CN112650026B

CN112650026B - Multilayer adhesive film based on single photoresist, patterning method and stripping method thereof

Info

Publication number: CN112650026B
Application number: CN202010152443.8A
Authority: CN
Inventors: 张文龙; 杨楚宏; 郑亚锐; 张胜誉; 冯加贵; 熊康林; 丁孙安
Original assignee: Tencent Technology Shenzhen Co Ltd; Suzhou Institute of Nano Tech and Nano Bionics of CAS
Current assignee: Tencent Technology Shenzhen Co Ltd; Suzhou Institute of Nano Tech and Nano Bionics of CAS
Priority date: 2020-03-06
Filing date: 2020-03-06
Publication date: 2022-09-30
Anticipated expiration: 2040-03-06
Also published as: CN112650026A

Abstract

The embodiment of the application provides a multilayer adhesive film based on a single photoresist, a patterning method and a stripping method thereof. The imaging method is a process for preparing an undercut structure by using a single photoresist, only the single photoresist is used for preparing a double-layer photoresist film with controllable film thickness of a first layer of photoresist, and the first layer of photoresist forms the undercut structure comprising a bottom photoresist after single development; and etching the bottom glue corresponding to the second through groove of the second layer of photoresist and the edge of the second through groove, exposing the substrate opposite to the second through groove after edge modification, and after forming a deposition layer, using a single photoresist removing stripping liquid to achieve the effect of complete stripping. The patterning method provided by the embodiment enables the subsequent stripping operation to be simple and the stripping effect to be good, and the actual size of the obtained structure to be deposited with the preset pattern is consistent with the defined size.

Description

Multilayer adhesive film based on single photoresist, patterning method and stripping method thereof

Technical Field

The application relates to the technical field of micro-nano processing, in particular to a multilayer adhesive film based on a single photoresist, a patterning method and a stripping method thereof.

Background

In the field of micro-nano processing technology, in order to obtain a structure with a micro-nano size, photoetching and stripping technologies are generally required to realize the micro-nano size.

In the conventional technology, a single positive photoresist or a single negative photoresist is usually adopted to form a photoresist layer with the thickness 1-3 times of the height of a deposition material to be prepared, and in the method, the photoresist side wall of a pattern area is directly contacted with the deposition material, and the deposition material on the photoresist side wall and the deposition material in a welding bump through groove are mutually adhered, so that the stripping of the photoresist is not easy, and the pattern appearance of the prepared deposition material is poor. Taking the solder bump in the flip chip bonding process as an example, the sidewall of the solder bump prepared by the conventional process exhibits random protrusions and depressions, as shown in fig. 1.

In the prior art, a multi-layer photoresist process is also adopted, so that in order to avoid adhesion between the side wall of the first layer of photoresist as a sacrificial layer and a deposition material, the undercut structure of the first layer of photoresist is made very large, and the graph of the joint of the first layer of photoresist and a substrate is far larger than the defined graph. When materials are deposited by methods such as electron beam evaporation, thermal evaporation, magnetron sputtering and the like, the temperature of the substrate is often increased in the experimental process, so that the probability that the deposited materials have transverse momentum is increased, that is, the bottom of the deposited materials tends to move laterally, the material cannot be blocked by a large undercut structure, and finally the size of the bottom of the deposited materials is far larger than that of the defined pattern. Again, the exemplary solder bumps are shown in fig. 2 and 3. For precision devices, the diffused part at the bottom of the deposited material can damage the surrounding circuit structure, and the quality of the device is affected.

Moreover, the process using multiple layers of photoresist in the prior art still generally has the following problems:

1) the combination of multiple photoresists is adopted, the requirements of baking time and temperature are different, and the solvents of different photoresists are mutually soluble, so that the compatibility between the photoresists is poor;

2) multiple times of development are needed, and the steps of fixing, drying and the like after the former development can affect the effect of the latter development;

3) multiple photoresist stripping liquids are needed for multiple same photoresists, and part of the photoresist stripping liquids can corrode the original material on the substrate;

4) the stripping effect is poor, and the problem of residual photoresist of part of photoresist or sacrificial layer is serious;

5) the thickness of the material to be stripped is limited, mainly by the maximum thickness of the single glue and the maximum thickness of the sacrificial layer.

Disclosure of Invention

The application aims at the defects of the prior art and provides a multilayer adhesive film based on a single photoresist, a patterning method and a stripping method thereof, which can keep the actual size of the prepared patterned deposition layer consistent with the defined pattern size.

In a first aspect, the present application provides a patterning method for a single photoresist-based multilayer adhesive film, the patterning method including the steps of:

coating a first layer of photoresist on the cleaned substrate, and carrying out first baking on the substrate coated with the first layer of photoresist;

carrying out first-time overall exposure on the substrate coated with the first layer of photoresist;

coating a second layer of photoresist on the first layer of photoresist, and carrying out second baking to form a bottom photoresist at the joint of the first layer of photoresist and the substrate;

performing local exposure on the substrate coated with the second layer of photoresist, and performing third baking on the substrate subjected to the local exposure for a second time length to cure the primer, wherein the second time length is less than the first time length;

developing and fixing the second layer of photoresist and the first layer of photoresist after the bottom photoresist is solidified in sequence to obtain a first layer of patterned photoresist and a second layer of patterned photoresist, wherein the first layer of patterned photoresist comprises the bottom photoresist and a first through groove positioned on one side of the bottom photoresist, which is far away from the substrate, and the second layer of patterned photoresist comprises a second through groove, and the orthographic projection of the second through groove on the substrate is positioned in the orthographic projection of the first through groove on the substrate;

and etching the bottom glue corresponding to the second through groove and the edge of the second through groove to expose the substrate opposite to the second through groove after edge modification.

Optionally, the first layer of photoresist and the second layer of photoresist are the same positive photoresist.

Optionally, the first baking is performed on the substrate coated with the first layer of photoresist, including:

and carrying out first baking on the substrate coated with the first layer of photoresist at the soft baking temperature of the first layer of photoresist.

Optionally, coating a first layer of photoresist on the cleaned substrate, comprising: and spin-coating the first layer of photoresist on the cleaned substrate in a one-time photoresist homogenizing mode or a multiple-time photoresist homogenizing mode.

Optionally, the first time period of blanket exposure of the substrate coated with the first layer of photoresist comprises: and carrying out comprehensive exposure on the substrate coated with the first layer of photoresist for a first time length by adopting an ultraviolet photoetching or laser direct writing mode, wherein the first time length is more than or equal to 50 s.

Optionally, performing a second baking to form a bottom glue at a connection between the first layer of photoresist and the substrate includes: and carrying out second baking on the substrate coated with the second layer of photoresist at the soft baking temperature of the first layer of photoresist so as to form a bottom glue at the joint of the first layer of photoresist and the substrate.

Optionally, the performing the local exposure on the substrate coated with the second layer of photoresist includes: and locally exposing the substrate coated with the second layer of photoresist by adopting a mask exposure mode of ultraviolet lithography or an exposure mode of laser direct writing.

Optionally, performing a third bake for a second duration on the partially exposed substrate, comprising: and carrying out third baking on the substrate after the local exposure for the second time length at the hardening temperature of the first layer of photoresist, wherein the second time length is less than or equal to 30 s.

Optionally, developing and fixing the second layer of photoresist and the first layer of photoresist cured by the primer in sequence, including: and developing the substrate after the primer is cured for the first time by using a single developing solution, and fixing by using deionized water as a fixing solution.

Optionally, etching the underfill corresponding to the second through groove and the edge of the second through groove includes: and etching the primer corresponding to the second through groove and the edge of the second through groove by adopting a physical etching or reactive etching method.

In a second aspect, an embodiment of the present application provides a method for stripping a single photoresist-based multilayer adhesive film, the stripping method including the above-mentioned method for patterning a single photoresist-based multilayer adhesive film, further including: forming a deposition layer on the remaining second layer of photoresist and the exposed substrate; and stripping the residual first layer of photoresist and the residual second layer of photoresist to obtain a deposition layer of the graph.

Optionally, stripping the remaining first layer of photoresist and the remaining second layer of photoresist to obtain a patterned deposition layer, including: and placing the substrate on which the deposition layer is formed in a photoresist stripping solution, and removing the residual first layer of photoresist and the residual second layer of photoresist at the temperature of 20-80 ℃ to obtain the deposition layer of the pattern, wherein the photoresist stripping solution comprises an organic solution and an inorganic alkaline solution.

In a third aspect, embodiments of the present application provide a single photoresist-based multilayer adhesive film, which is obtained by the above-mentioned patterning method of the single photoresist-based multilayer adhesive film.

The technical scheme provided by the embodiment of the application has the following beneficial technical effects:

1) the invention uses single photoresist, the compatibility among the multilayer photoresist films is good, and the multilayer photoresist films containing the bottom photoresist undercut structure can be obtained only by using single developing solution for one-time development;

2) the invention adopts a multilayer photoresist structure, and the undercut structure of the sacrificial layer avoids the problem of difficult stripping caused by adhesion of materials and the side wall when a single-layer positive/negative photoresist is used for stripping in the traditional process;

3) according to the invention, a thin layer of base glue is prepared on the sacrificial layer through a specific process flow, the base glue is removed through an etching method, the side wall angle of a second layer of photoresist for defining a pattern is modified, the bottom of a deposition material is blocked by the thin layer of base glue and does not laterally diffuse, and the size of the deposition material is consistent with that of the defined pattern;

4) the invention uses a single photoresist, only needs a single photoresist removing solution when removing the photoresist and stripping, and avoids the problem that the process of combining the positive photoresist and the negative photoresist in the traditional process needs to use a plurality of residual photoresists;

5) the photoresist used as the sacrificial layer has wider selection surface, can be thickened by a method of even multiple layers of photoresist, and can be used for stripping materials with different thicknesses by selecting the photoresist with proper thickness.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The foregoing and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is an image taken with an electron microscope of a conventional process for preparing a solder bump;

FIG. 2 is a schematic view of a prior art solder bump made using multiple layers of photoresist;

FIG. 3 is an electron microscope image of a prior art solder bump made using multiple layers of photoresist;

FIG. 4 is a schematic flowchart illustrating a method for patterning a multilayer adhesive film based on a single photoresist according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram illustrating a process flow of a method for patterning a multilayer adhesive film based on a single photoresist according to an embodiment of the present disclosure;

FIG. 6 is an image of a scanning electron microscope on a sidewall of a single photoresist based multi-layer adhesive film according to an embodiment of the present disclosure;

FIG. 7 is a scanning electron microscope image of the sidewall of the single photoresist based multilayer adhesive film labeled in FIG. 6;

FIG. 8 is an optical microscope image of a multilayer photoresist film based on a single photoresist provided by an embodiment of the present application;

FIG. 9 is a schematic flow chart of a method for peeling off a multi-layer adhesive film based on a single photoresist according to an embodiment of the present application;

FIG. 10 is a schematic view of a process flow of steps S206-S208 in a method for peeling a multi-layer adhesive film based on a single photoresist according to an embodiment of the present application;

fig. 11 is an image of a scanning electron microscope of a bonding bump according to an embodiment of the present application.

Reference numerals:

1-a substrate; 2-a first layer of photoresist; 201-a first through slot; 202-base glue; 3-a second layer of photoresist; 301-a second through slot; 4-patterned deposition layer.

Detailed Description

Reference will now be made in detail to the present application, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar parts or parts having the same or similar functions throughout. In addition, if a detailed description of the known art is unnecessary for the features of the present application shown, it is omitted. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

It will be understood by those within the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Several terms referred to in this application will first be introduced and explained:

indium columns: the columnar indium metal deposited on the specific position of the substrate sample by means of evaporation coating and the like is often used as a welding spot.

Exposure and development: a micro-nano processing technology mainly relates to ultraviolet lithography, namely coating photoresist on the surface of a substrate sample, irradiating ultraviolet light to the surface of the substrate through a mask, changing the property of the irradiated part of the photoresist by photochemical reaction, and dissolving the area which reacts with the light into a specific solution to achieve the purpose of making a specific graph on the substrate.

Undercutting: the English Chinese translation of "undercut" is a photoresist structure, and means that the bottom of the photoresist is wider than the top, the side wall is gradually expanded outwards from the top to the bottom, the photoresist section is in a regular trapezoid shape, and the photoresist also can be in a convex shape after process improvement.

Primer coating: the photoresist at the interface of the substrate surface coated with the photoresist is denatured due to a plurality of factors such as substrate heating, chemical reaction in the developing process, oxidation in the air and the like, and is not dissolved in common developing solution any more, and belongs to one of residual photoresist. In the field of micro-nano processing, a photoresist removing machine and other chemical or physical etching methods are generally used for removing the primer.

Sacrificial layer: in the lift-off technique, in order to lift off the deposited material in the non-defined area, a photoresist is coated on the substrate in the non-defined area; when stripping, the layer of photoresist is dissolved in a specific solution, and the material deposited on the upper layer is stripped, and the layer of photoresist is called a sacrificial layer.

Stripping: lift-off technology (lift-off technology) is a process in which a substrate is coated with photoresist, exposed and developed, then the photoresist with a certain pattern is used as a mask, required materials such as metal and the like are deposited by evaporation and other methods, then the photoresist is removed, simultaneously, the unnecessary materials on the photoresist film are stripped off, and finally, only the material structure with the original pattern is left on the substrate.

The following describes the technical solutions of the present application and how to solve the above technical problems with specific embodiments.

The present embodiment provides a patterning method of a multilayer adhesive film based on a single photoresist, as shown in fig. 4 and 5, the patterning method provided by the present embodiment includes the following steps:

s101: a first layer of photoresist 2 is coated on the cleaned substrate 1, and the substrate 1 coated with the first layer of photoresist 2 is subjected to a first baking.

Specifically, the first layer of photoresist 2 may be a positive photoresist coated on the cleaned substrate by spin coating. In this step, the substrate coated with the first layer of photoresist is subjected to a first baking including: the substrate 1 of the first layer of photoresist 2 is subjected to a first bake at a soft bake temperature of the first layer of photoresist 2. The soft baking temperatures of different photoresists are different, and for example, the soft baking temperature of the AZ4620 positive photoresist is 100 ℃.

S102: the substrate 1 coated with the first layer of photoresist 2 is subjected to a first long blanket exposure.

Specifically, the substrate 1 coated with the first layer of photoresist 2 is subjected to full exposure for a first time length in an ultraviolet lithography or laser direct writing mode, wherein the first time length is greater than or equal to 50 s. Namely, the substrate 1 coated with the first layer of photoresist 2 is subjected to overall exposure for a long time, so that the first layer of photoresist 2 is completely converted into a sacrificial layer capable of being dissolved in a developing solution, and the subsequent stripping operation is convenient to realize.

S103: and coating a second layer of photoresist 3 on the first layer of photoresist 2, and carrying out second baking to form a bottom glue 202 at the joint of the first layer of photoresist 2 and the substrate 1.

Specifically, the second layer of photoresist and the first layer of photoresist are the same photoresist, and the second baking is performed to form a primer 202 at the joint of the first layer of photoresist and the substrate, including: and carrying out second baking on the substrate 1 coated with the second layer of photoresist 3 at the soft baking temperature of the first layer of photoresist 2, so that a bottom glue 202 is formed at the joint of the first layer of photoresist 2 and the substrate 1.

S104: and carrying out local exposure on the substrate coated with the second layer of photoresist, and carrying out third baking on the substrate subjected to the local exposure for a second time length to cure the primer, wherein the second time length is less than the first time length.

Specifically, the local exposure of the substrate 1 coated with the second layer of photoresist 3 includes: and carrying out local exposure on the substrate 1 coated with the second layer of photoresist 3 by adopting a mask exposure mode of ultraviolet lithography or a laser direct writing exposure mode.

Specifically, the substrate 1 after the partial exposure is subjected to the third baking for the second duration, which includes: and carrying out third baking on the substrate 1 after the local exposure for a second time length at the film hardening temperature of the first layer of photoresist 2, wherein the second time length is less than or equal to 30 s.

S105: developing and fixing the second layer of photoresist 3 and the first layer of photoresist 2 solidified by the base glue 202 in sequence to obtain the patterned first layer of photoresist 2 and the patterned second layer of photoresist 3, wherein the patterned first layer of photoresist 2 comprises the base glue 202 and a first through groove 201 which is positioned on one side of the base glue 202 far away from the substrate 1, the patterned second layer of photoresist 3 comprises a second through groove 302, and the orthographic projection of the second through groove 301 on the substrate 1 is positioned in the orthographic projection of the first through groove 201 on the substrate 1. I.e., the patterned first layer of photoresist 2 and the patterned second layer of photoresist 3 form an undercut structure.

S106: and etching the bottom glue 202 corresponding to the second through groove 301 and the edge of the second through groove 301 to expose the substrate 1 opposite to the second through groove 301 with the modified edge.

The embodiment of the invention discloses a patterning method of a multilayer photoresist film based on a single photoresist, which comprises the steps of uniformly coating a first layer of photoresist 2 on a cleaned substrate, and carrying out first baking to evaporate a solvent of the first layer of photoresist 2; then, carrying out overall exposure to enable the first layer of photoresist 2 to be fully reflected with light and be easily dissolved in a developing solution; then, uniformly coating a second layer of photoresist 3 which is the same as the first layer of photoresist 2 on the first layer of photoresist 2 and drying; exposing a pattern on the second layer of photoresist 3 by using a mask; developing, wherein only the area of the second layer of photoresist 3 which reacts with light is dissolved in a developing solution, and all areas of the first layer of photoresist 2 are fully reflected by light, so that the second layer of photoresist is gradually and transversely dissolved along with the extension of developing time to form an undercut structure, and the transverse size of the undercut structure can be adjusted by controlling the developing time; etching the bottom glue opposite to the second through groove 301 by using equipment such as a photoresist remover and the like and introducing etching gas, and simultaneously modifying the side wall angle of the second layer of photoresist 3; forming a deposition layer on the substrate 1 having the undercut structure by using a coating method such as electron beam evaporation, so that the sidewall of the deposition layer is not adhered to the sidewall of the photoresist; and placing the substrate 1 with the deposited layer formed in a photoresist stripping solution, releasing two layers of photoresist, stripping the material of the non-pattern-defining area on the photoresist cleanly along with the release of the photoresist, and leaving the material of the pattern-defining area on the substrate. The actual size of the obtained deposition layer with the pattern is consistent with the defined size, and the obtained structure to be deposited with the preset pattern has good appearance.

Based on the same inventive concept, the present embodiment provides a single photoresist-based multi-layered photoresist film manufactured by the single photoresist-based multi-layered photoresist film patterning method of the above embodiments.

Specifically, as shown in fig. 6 and 7, the through groove of the multilayer photoresist film based on a single photoresist has an undercut structure, which can effectively prevent the material to be deposited from contacting the sidewall of the first through groove 201 of the first layer of photoresist 2, can improve the surface topography of the obtained sidewall with the patterned deposition layer, and the first layer of photoresist 2 as the sacrificial layer does not contact the sidewall of the patterned deposition layer, thereby facilitating the subsequent lift-off operation.

As shown in fig. 8, taking the multilayer photoresist film layer with the welding bumps arranged in an array as an example, the patterned multilayer photoresist film also has through grooves arranged in an array, and the second through grooves 301 arranged in an array on the second layer of photoresist 3 can be seen in a top view.

Based on the same inventive concept, the present embodiment provides a method for stripping a multilayer photoresist film based on a single photoresist, as shown in fig. 9 and 10, the method includes the patterning method of the multilayer photoresist film based on a single photoresist in the above embodiment, i.e., step S201 to step S206 shown in fig. 9, which is the same as step S101 to step S106 in the patterning method of the multilayer photoresist film based on a single photoresist in the above embodiment, and is not repeated herein.

The peeling method provided by the embodiment further comprises the following steps:

s207: deposited layers are formed on the remaining second layer of photoresist 3 and on the exposed substrate 1.

S208: and stripping the remaining first layer of photoresist 2 and the remaining second layer of photoresist 3 to obtain a patterned deposition layer 4.

Specifically, the substrate 1 with the deposited layer formed is placed in a photoresist stripping solution, and the remaining first layer of photoresist 2 and the remaining second layer of photoresist 3 are removed at a temperature of 20-80 ℃ to obtain a patterned deposited layer 4, wherein the photoresist stripping solution comprises an organic solution and an inorganic alkaline solution.

In the method for peeling off a multilayer adhesive film based on a single photoresist provided by this embodiment, the first layer of photoresist 2 is subjected to a long-time exposure treatment to completely convert the first layer of photoresist 2 into a sacrificial layer, and a pattern with an undercut structure is formed, and the edges of the primer 202 corresponding to the second through groove 301 and the second through groove 301 are etched, so that it can be ensured that a material to be deposited is prevented from laterally diffusing on the substrate 1 in a subsequent deposition process of the material to be deposited, and thus it is ensured that a pattern size of an obtained patterned deposition layer is consistent with a defined pattern size.

Specifically, taking the structure 4 to be deposited with a preset pattern as an indium column as an example, the indium column obtained by the lift-off method provided by this embodiment is shown in fig. 11, where the junction of the indium column and the substrate 1 has no lateral diffusion, that is, the actual size of the indium column is the same as the defined size, and the obtained indium column has a smooth surface and a good appearance.

For ease of understanding, a specific example is provided below, and the stripping method provided in the present application is illustrated by taking the preparation of indium columns as an example.

This example used AZ4620 positive photoresist to strip a metal indium film of about 8 μm thickness to form indium columns of 8 μm height:

step 1: selecting a silicon substrate as a substrate, placing the cleaned silicon substrate on a spin-coating spin coater, selecting an AZ4620 positive photoresist to form a first layer of photoresist, uniformly dripping the AZ4620 positive photoresist on the center of the silicon substrate, operating at 300-800 rpm for 1-5 s, and operating at 1000-2000 rpm for 30-60 s for spin coating to obtain a first layer of photoresist with the thickness of 8.5-12 mu m. And then, placing the silicon substrate after the glue homogenizing on a heating plate, and baking the silicon substrate for 120s at 100 ℃ to evaporate the solvent of the AZ4620 positive photoresist to dryness.

Step 2: a silicon substrate with a first layer of photoresist is exposed using a Flood exposure (i.e., Flood-E) mode of an ultraviolet lithography machine. For example, the silicon substrate with the first layer of photoresist is fully exposed with power of 850-1000W and time of 60-120 s, so that the first layer of photoresist fully reacts with light.

And step 3: and (3) placing the silicon substrate subjected to the step (2) on a spin-coating type spin coater, selecting an AZ4620 positive photoresist to spin-coat to form a second layer of photoresist, and then operating at 300-800 rpm for 3s, and then operating at 3000-5000 rpm for 30-60 s to obtain a second layer of photoresist with the thickness of 5-7 microns. And then, placing the substrate on a heating plate, baking for 60-150 s at 100 ℃, carrying out second baking on the second layer of photoresist, and forming a bottom photoresist on the bottom of the first layer of photoresist. The required thickness of the primer is slightly different aiming at different lateral diffusion tendencies of different deposition materials in the deposition process, and the thickness of the primer can be controlled by the duration of the second baking.

And 4, step 4: and (3) using a contact mode (Hard) of an ultraviolet lithography machine, carrying out local exposure by adopting a mask plate to define a pattern, placing the silicon substrate subjected to the local exposure on a heating plate for 10-30 s at 110 ℃, and carrying out third baking to cure the primer, wherein the 110 ℃ is the hardening temperature of the AZ4620 positive photoresist.

And 5: the silicon substrate after step 4 was placed in a 25% tetramethylammonium hydroxide (TMAH) solution diluted with deionized water (25% TMAH: H) ₂ O & lt1: 8), developing for 100 s-200 s, taking out, putting into deionized water, fixing for 30 s-60 s, taking out, and drying by using nitrogen gas, wherein a double-layer photoresist film with a bottom glue and an undercut structure is formed on the silicon substrate. Specifically, the display time is determined according to actual requirements to obtain undercut structures of different degrees.

Step 6: and (5) placing the silicon substrate sample obtained after the step (5) into a photoresist remover, etching off the bottom glue opposite to the second through groove under the conditions of pure oxygen environment of 100-300 sccm, power of 200-500W and etching time of 1-5 min, and modifying the angle of the side wall of the second through groove of the second layer of photoresist.

And 7: using a thermal evaporation coating device, and the vacuum degree is 9 multiplied by 10 ^-4 An indium metal film (In) having a thickness of about 8 μm was deposited under Pa. Due to the bottom cutting structure, the side wall of the indium metal is not adhered to the double-layer adhesive film, and meanwhile, due to the etched primer, the lateral diffusion of the bottom of the indium metal is blocked.

And 8: and (3) soaking the silicon substrate subjected to the step (7) in acetone to release the AZ4620 double-layer positive glue, stripping the silicon substrate at room temperature for 24 hours, and then ultrasonically cleaning the sample by using acetone, isopropanol and deionized water in sequence to obtain the indium columns with the same size as the defined pattern.

Through the above steps, indium columns having a height of 8 μm can be obtained. In specific implementation, the thicknesses of the first layer of photoresist and the second layer of photoresist to be formed are determined according to the difference of the heights of the indium columns, generally, the thickness of the first layer of photoresist should meet the requirement of forming an undercut structure with a proper size, and the sum of the thicknesses of the first layer of photoresist and the second layer of photoresist is slightly more than 2 times of the height of the indium columns, that is, the height difference between the upper surface of the second layer of photoresist and the tops of the indium columns is slightly more than the height of the indium columns, so as to avoid the indium material deposited on the second layer of photoresist and the indium material forming the indium columns from being connected together.

It should be noted that the method provided by the present application can also be used for manufacturing other patterned metal layers and non-metal layers, for example, structures of metal materials such as metal electrodes and metal pins, and oxide materials such as a crossover bridge (an insulating layer located between two conductive layers when forming a bridge).

In addition, the above description of the embodiments is only for assisting understanding of the method of the present invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Those of skill in the art will appreciate that the various operations, methods, steps in the processes, acts, or solutions discussed in this application can be interchanged, modified, combined, or eliminated. Further, various operations, methods, steps, measures, schemes in the various processes, methods, procedures that have been discussed in this application may be alternated, modified, rearranged, decomposed, combined, or eliminated. Further, steps, measures, schemes in the prior art having various operations, methods, procedures disclosed in the present application may also be alternated, modified, rearranged, decomposed, combined, or deleted.

In the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present application.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in this application will be understood to be a specific case for those of ordinary skill in the art.

The particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

It should be understood that, although the steps in the flowcharts of the figures are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and may be performed in other orders unless otherwise indicated herein. Moreover, at least a portion of the steps in the flow chart of the figure may include multiple sub-steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of execution is not necessarily sequential, but may be performed alternately or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

The foregoing is only a few embodiments of the present application and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present application, and that these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A method for patterning a multilayer adhesive film based on a single photoresist is characterized by comprising the following steps:

coating a second layer of photoresist on the first layer of photoresist, and carrying out second baking to form a bottom glue at the joint of the first layer of photoresist and the substrate;

locally exposing the substrate coated with the second layer of photoresist, and performing third baking on the substrate subjected to local exposure for a second time at the hardening temperature of the first layer of photoresist to cure the primer, wherein the second time is less than the first time, and the second time is less than or equal to 30 s;

developing and fixing the second layer of photoresist and the first layer of photoresist after the bottom photoresist is solidified in sequence to obtain a patterned first layer of photoresist and a patterned second layer of photoresist, wherein the patterned first layer of photoresist comprises the bottom photoresist and a first through groove positioned on one side of the bottom photoresist, which is far away from the substrate, and the patterned second layer of photoresist comprises a second through groove, and the orthographic projection of the second through groove on the substrate is positioned in the orthographic projection of the first through groove on the substrate;

and etching the primer corresponding to the second through groove and the edge of the second through groove to expose the substrate opposite to the second through groove after edge modification.

2. The patterning process of claim 1, wherein the first layer of photoresist and the second layer of photoresist are the same positive photoresist.

3. The patterning process of claim 2, wherein the first baking of the substrate coated with the first layer of photoresist comprises:

4. The patterning process of claim 1, wherein applying a first layer of photoresist on the cleaned substrate comprises:

and spin-coating the first layer of photoresist on the cleaned substrate in a one-time photoresist homogenizing mode or a multiple-time photoresist homogenizing mode.

5. The patterning process of claim 1, wherein the first blanket exposure of the substrate after the first layer of photoresist is applied comprises:

and carrying out comprehensive exposure on the substrate coated with the first layer of photoresist for a first time length by adopting an ultraviolet photoetching or laser direct writing mode, wherein the first time length is more than or equal to 50 s.

6. The patterning process of claim 1, wherein performing a second bake to form a primer in the first layer of photoresist at a junction with the substrate comprises:

and carrying out second baking on the substrate coated with the second layer of photoresist at the soft baking temperature of the first layer of photoresist so as to form a base glue at the joint of the first layer of photoresist and the substrate.

7. The patterning process of claim 1, wherein the exposing the substrate after the applying the second layer of photoresist comprises:

and locally exposing the substrate coated with the second layer of photoresist by adopting a mask exposure mode of ultraviolet lithography or a laser direct writing exposure mode.

8. The patterning method according to claim 1, wherein developing and fixing the second layer of the photoresist and the first layer of the photoresist after the primer is cured are performed in sequence, and the developing and fixing method includes:

and developing the substrate after the primer is cured for the first time by using a single developing solution, and fixing by using deionized water as a fixing solution.

9. The patterning method according to claim 1, wherein etching the underfill corresponding to the second through groove and an edge of the second through groove includes:

and etching the primer corresponding to the second through groove and the edge of the second through groove by adopting a physical etching or reactive etching method.

10. A method for stripping the multilayer adhesive film based on a single photoresist, comprising the method for patterning the multilayer adhesive film based on a single photoresist of any one of claims 1 to 9, further comprising:

forming a deposition layer on the remaining second layer of photoresist and the exposed substrate;

and stripping the residual first layer of photoresist and the residual second layer of photoresist to obtain a patterned deposition layer.

11. The lift-off method of claim 10, wherein stripping the remaining first layer of photoresist and the remaining second layer of photoresist to provide a patterned deposition layer comprises:

and placing the substrate with the deposited layer formed in a photoresist stripping solution, and removing the residual first layer of photoresist and the residual second layer of photoresist at the temperature of 20-80 ℃ to obtain the patterned deposited layer, wherein the photoresist stripping solution comprises an organic solution and an inorganic alkaline solution.

12. A single photoresist-based multilayer adhesive film, wherein the multilayer adhesive film is prepared by the method for patterning a single photoresist-based multilayer adhesive film according to any one of claims 1 to 9.