Microelectronic photoetching lift-off processing method and microelectronic device

Abstract

The invention provides a microelectronic photoetching lift-off processing method and a microelectronic device. The processing method comprises the following steps: providing a substrate; one end of the substrate is coated with a photoresist material layer, and the photoresist material layer at least comprises a diazonaphthoquinone photosensitizer; putting the epitaxial wafer coated with the photoresist material layer into a first developing solution for soaking so as to form a dissolution-resistant layer on the surface of the photoresist material layer; performing pattern exposure processing on the epitaxial wafer according to a preset pattern; carrying out developing treatment on the exposed epitaxial wafer by adopting a second developing solution, and dissolving the dissolution-resistant layer subjected to the exposure reaction and the photoresist material layer at the bottom of the dissolution-resistant layer so as to form a preset pattern on the substrate; and depositing a metal material on the surface of the epitaxial wafer on which the preset pattern is formed, and removing the residual photoresist material layer to form a metal pattern on the surface of the substrate so as to complete photoetching lift-off operation. The microelectronic photoetching lift-off processing method disclosed by the invention is high in precision and good in pattern transfer quality.

Description

Technical Field

[0001] The invention relates to the field of microelectronic manufacturing, and in particular to a microelectronic photolithography lift-off processing method and a microelectronic device. Background Art

[0002] In the field of microelectronics manufacturing, photolithography (photolithography) is one of the key processes for achieving precision graphics production. As the manufacturing progress nodes of integrated circuits and micro-electromechanical systems continue to shrink, the resolution, accuracy and stability of the photolithography process are urgently required to increase. Lift-Off technology is a common method for graphics production, especially suitable for generating thin film graphics. This technology is widely used in the microelectronics, optoelectronics and semiconductor industries.

[0003] The traditional photolithography lift-off process usually includes processes such as photoresist etching, selective exposure, metal deposition and lift-off. This process requires controlling the solubility of the photoresist material so that the desired pattern can be formed in the etching or metal deposition step. At present, traditional photoresist materials are mainly selectively exposed to the photoresist material by controlling the shape of the mask plate, and then removed by etching liquid. As the pattern size decreases and the line width becomes narrower, the etching effect of traditional photoresist materials cannot meet the requirements of high resolution, and improper corrosion may occur in the edge area of ​​selective exposure, affecting the pattern quality, and then affecting the stability and reliability of metal pattern production. Summary of the invention

[0004] Based on this, the purpose of the present invention is to provide a microelectronic lithography lift-off processing method and a microelectronic device to solve the problems existing in the prior art.

[0005] One aspect of the present invention provides a microelectronics photolithography lift-off processing method, comprising the following steps: providing a substrate; Coating a photoresist material layer at one end of the substrate, wherein the photoresist material layer at least includes a diazonaphthoquinone photosensitizer; The epitaxial wafer coated with the photoresist material layer is placed in a first developer for immersion to perform an azo coupling reaction on the surface of the photoresist material layer to form a dissolution-resistant layer; Performing pattern exposure processing on the epitaxial wafer after being soaked in the first developer according to a preset pattern, so as to cause an exposure reaction on the dissolution-resistant layer; Using a second developer to develop the epitaxial wafer after the exposure reaction, dissolving the dissolution-resistant layer after the exposure reaction and the photoresist material layer at the bottom thereof, so as to form a preset pattern on the substrate; A metal material is deposited on the surface of the epitaxial wafer forming a preset pattern, and the remaining photoresist material layer is removed to form a metal pattern on the surface of the substrate, completing the photolithography lift-off operation.

[0006] The beneficial effects of the present invention are as follows: the microelectronic lithography lift-off processing method provided by the present application first provides a substrate, then coats one end of the substrate with a photoresist material layer, and immerses the epitaxial wafer coated with the photoresist material layer in a first developer to perform an azo coupling reaction on the surface of the photoresist material layer to form a dissolution-resistant layer; then, according to a preset pattern, the epitaxial wafer soaked in the first developer is subjected to pattern exposure processing to cause an exposure reaction on the dissolution-resistant layer; and a second developer is used to perform a development processing on the epitaxial wafer after the exposure reaction to dissolve the dissolution-resistant layer that has undergone the exposure reaction and the photoresist material layer at the bottom of the dissolution-resistant layer to form a dissolution-resistant layer. A preset pattern is formed on a substrate; since a dissolution-resistant layer is generated by an azo coupling reaction, the solubility of the unexposed area is improved when the second developer is used for dissolution, and the stability of the pattern transfer is significantly improved. The dissolution error can be accurately controlled by the azo coupling reaction, and a pattern with high recovery and clear edges can be generated. Then, a metal material is deposited on the surface of the epitaxial wafer forming the preset pattern, and finally all photoresist material layers are removed to obtain a microelectronic device. The microelectronic lithography lift-off processing method provided in the present application is suitable for sub-micron or even nanometer-level pattern production, has high precision and good pattern transfer quality, and is suitable for large-scale promotion.

[0007] Preferably, the photoresist material layer further comprises phenolic resin, and the thickness of the photoresist material layer is 0.85 μm-0.9 μm.

[0008] Preferably, the first developer is AZ300MIF developer, the immersion temperature is 20° C.-25° C., and the immersion time is 60s-120s.

[0009] Preferably, after the dissolution-resistant layer is formed on the surface of the photoresist material layer, before the epitaxial wafer immersed in the first developer is subjected to pattern exposure processing according to a preset pattern, the microelectronic lithography lift-off processing method also includes: pre-baking the epitaxial wafer to remove the solvent on the surface of the epitaxial wafer, the pre-baking temperature is 80°C-100°C, and the time is 50s-70s.

[0010] Preferably, the step of performing pattern exposure processing on the epitaxial wafer after being soaked in the first developer according to a preset pattern so as to cause an exposure reaction on the dissolution-resistant layer comprises: Placing the epitaxial wafer after the first development immersion on a stage; Arranging an i-line exposure device above an end of the epitaxial wafer away from the substrate for exposure processing; The ultraviolet rays irradiated by the i-line exposure device react with the diazonaphthoquinone photosensitizer in the dissolution-resistant layer to convert the diazonaphthoquinone photosensitizer in the exposure area into a carboxyl group.

[0011] Preferably, the second developer is a 2.38% tetramethylammonium hydroxide solution, the developing method is continuous spraying development, the developing temperature is 20° C.-25° C., and the developing time is 90s-120s; The second developer reacts with the carboxyl group converted from the diazonaphthoquinone photosensitizer to generate a product soluble in water.

[0012] Preferably, after the exposure reaction occurs on the dissolution-resistant layer and before the development process is performed, the microelectronic lithography lift-off process further comprises: performing a post-baking process on the epitaxial wafer, wherein the post-baking temperature is 90° C.-140° C. and the time is 30s-60s.

[0013] Preferably, after post-baking and before developing, the microelectronic lithography lift-off processing method further comprises: flood irradiating the surface of the epitaxial wafer away from the substrate, wherein the exposure intensity of the flood irradiation is 0-75 mJ / cm².

[0014] Another aspect of the present invention provides a microelectronic device, which is manufactured by the microelectronic photolithography lift-off processing method.

[0015] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flow chart of the microelectronics photolithography lift-off processing method provided by the present invention; Figure 2 A schematic diagram of the structure of the epitaxial wafer provided by the present invention after being coated with a photoresist material layer; Figure 3 A schematic diagram of the structure of the epitaxial wafer provided by the present invention after a dissolution-resistant layer is formed; Figure 4 A schematic diagram of the structure of the epitaxial wafer provided by the present invention being exposed by using an exposure device; Figure 5 A schematic diagram of the structure after a preset pattern is formed on the epitaxial wafer substrate provided by the present invention; Figure 6 This is a schematic diagram of the structure after a metal layer is deposited on the surface of the epitaxial wafer provided by the present invention; Figure 7 This is a schematic diagram of the structure after a metal pattern is formed on the surface of the epitaxial wafer substrate provided by the present invention.

[0017] Description of main component symbols: 10. substrate; 20. photoresist layer; 30. dissolution-resistant layer; 40. exposure equipment; 50. preset pattern; 60. metal layer; 70. metal pattern.

[0018] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0020] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing optional embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0022] The present invention provides a microelectronics photolithography lift-off processing method, such as Figure 1 As shown, the microelectronics photolithography lift-off processing method includes steps S10-S60: S10, providing a substrate.

[0023] S20, coating a photoresist material layer at one end of the substrate, wherein the photoresist material layer at least includes a diazonaphthoquinone photosensitizer; S30, placing the epitaxial wafer coated with the photoresist material layer into a first developer for immersion, so as to perform an azo coupling reaction on the surface of the photoresist material layer to form a dissolution-resistant layer; S40, performing pattern exposure processing on the epitaxial wafer after being soaked in the first developer according to a preset pattern, so as to cause an exposure reaction on the dissolution-resistant layer; S50, using a second developer to develop the epitaxial wafer after the exposure reaction, dissolving the dissolution-resistant layer after the exposure reaction and the photoresist material layer at the bottom of the dissolution-resistant layer, so as to form a preset pattern on the substrate; S60, depositing a metal material on the surface of the epitaxial wafer forming a preset pattern, removing the remaining photoresist material layer to form a metal pattern on the surface of the substrate, and completing a photolithography lift-off operation.

[0024] In specific implementation, Figure 2 As shown, first, a layer of photoresist material is uniformly coated on the provided substrate 10. The photoresist material can use AZ® 7900 Resist photoresist material. The photoresist material layer 20 mainly includes phenolic resin (NovolakResin) and PAC (Photo Active compound) photosensitizer. The PAC photosensitizer can use diazonaphthoquinone (DNQ) photosensitizer. Optionally, the thickness of the photoresist material layer is 0.85μm-0.9μm; then the epitaxial wafer coated with the photoresist material layer is immersed in a first developer. The first developer can be AZ300MIF developer. The immersion temperature is 20℃-25℃ and the immersion time is 60s-120s. The photoresist material layer can undergo an azo coupling reaction with the first developer, such as Figure 3 As shown, a dissolution-resistant layer 30 is formed; then, according to the designed pattern, the epitaxial wafer after being immersed in the first developer is subjected to pattern exposure processing by an exposure device 40, such as Figure 4 shown.

[0025] Furthermore, after the dissolution-resistant layer is formed on the surface of the photoresist material layer and before the graphic exposure process is performed, the microelectronic lithography lift-off process method also includes: pre-baking the epitaxial wafer to remove the solvent on the surface of the epitaxial wafer, the pre-baking temperature is 80°C-100°C, and the time is 50s-70s. Pre-baking can reduce the risk of deformation in subsequent processing steps.

[0026] Optionally, the exposure treatment step includes: placing the epitaxial wafer after the first development immersion on a stage; Arranging an i-line exposure device above an end of the epitaxial wafer away from the substrate for exposure processing; The ultraviolet rays irradiated by the i-line exposure device react with the diazonaphthoquinone photosensitizer in the dissolution-resistant layer to convert the diazonaphthoquinone photosensitizer in the exposure area into a carboxyl group.

[0027] After the exposure treatment, the DNQ in the photoresist material layer can be converted into carboxyl groups. After the dissolution-resistant layer is selectively exposed, carboxyl groups that can react with the second developer are generated. The second developer reacts with the carboxyl groups to dissolve the dissolution-resistant layer that has undergone the exposure reaction. The photoresist material layer at the bottom of the dissolution-resistant layer is corroded and dissolved by the second developer until the surface of the substrate is reached to form a preset pattern 50 on the substrate. The dissolved epitaxial wafer is as follows: Figure 5 shown.

[0028] Optionally, the second developer can be a 2.38% tetramethylammonium hydroxide (TMAH) solution, the development method is continuous spray development, the development temperature is 20°C-25°C, and the development time is 90s-120s; the second developer reacts with the carboxyl group converted from the diazonaphthoquinone photosensitizer to generate a water-soluble product, and the exposure and development steps are: DNQ→UV exposure→carboxyl group; carboxyl group+TMAH→soluble product. After the development operation, a precise metal material deposition graphic structure can be formed. Furthermore, through appropriate process parameters, the undercut metal material deposition sidewall morphology can be obtained; then the metal layer 60 is deposited on the surface of the epitaxial wafer, and the epitaxial wafer after the metal deposition is as follows Figure 6 Finally, the device is lifted off to remove the remaining photoresist layer, and a metal pattern 70 is formed on the surface of the substrate. Figure 7 shown.

[0029] Furthermore, after the exposure reaction occurs on the dissolution-resistant layer and before the development process is performed, the microelectronic lithography lift-off process also includes: performing a post-baking process on the epitaxial wafer, the post-baking temperature is 90°C-140°C, and the time is 30s-60s. Post-baking after exposure can, on the one hand, allow the surface photoresist immersed in the developer to fully react with azo coupling reaction and stabilize the azo coupling structure; on the other hand, it can also accelerate the chemical changes of the photosensitizer during the exposure process and stabilize the pattern in the photoresist layer.

[0030] Furthermore, after post-baking and before developing, the microelectronic lithography lift-off method further includes: flood irradiating the surface of the epitaxial wafer away from the substrate, the exposure intensity of the flood irradiation being 0-75 mJ / cm². The flood irradiation is performed once on the photoresist material to fully cover the photosensitive agent at the edge, which can effectively improve the edge accuracy of the pattern and reduce the edge roughness phenomenon during the development and removal process.

[0031] In summary, the microelectronic lithography lift-off processing method provided by the present application first provides a substrate, then coats one end of the substrate with a photoresist material layer, and immerses the epitaxial wafer coated with the photoresist material layer in a first developer to perform an azo coupling reaction on the surface of the photoresist material layer to form a dissolution-resistant layer; then, the epitaxial wafer soaked in the first developer is subjected to pattern exposure processing according to a preset pattern to cause an exposure reaction on the dissolution-resistant layer; and the epitaxial wafer after the exposure reaction is subjected to a development processing using a second developer to dissolve the dissolution-resistant layer that has undergone the exposure reaction and the photoresist material layer at the bottom of the dissolution-resistant layer. A preset pattern is formed on a substrate; since a dissolution-resistant layer is generated by an azo coupling reaction, the solubility of the unexposed area is improved when the second developer is used for dissolution, and the stability of the pattern transfer is significantly improved. The dissolution error can be accurately controlled by the azo coupling reaction, and a pattern with high recovery and clear edges can be generated. Then, a metal material is deposited on the surface of the epitaxial wafer forming the preset pattern, and finally all photoresist material layers are removed to obtain a microelectronic device. The microelectronic lithography lift-off processing method provided in the present application is suitable for sub-micron or even nanometer-level pattern production, with high precision and good pattern transfer quality.

[0032] It should be noted that the above implementation process is only to illustrate the feasibility of the present application, but this does not mean that the microelectronic lithography lift-off processing method of the present application has the above-mentioned implementation processes. On the contrary, as long as the microelectronic lithography lift-off processing method of the present application can be implemented, it can be included in the feasible implementation plan of the present application.

[0033] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0034] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the attached claims.

Claims

1. A microelectronic lithography lift-off processing method, characterized in that: The following steps are involved: providing a substrate; Coating a photoresist material layer at one end of the substrate, wherein the photoresist material layer at least includes a diazonaphthoquinone photosensitizer; The epitaxial wafer coated with the photoresist material layer is placed in a first developer for immersion to perform an azo coupling reaction on the surface of the photoresist material layer to form a dissolution-resistant layer; Performing pattern exposure processing on the epitaxial wafer after being soaked in the first developer according to a preset pattern, so as to cause an exposure reaction on the dissolution-resistant layer; Using a second developer to develop the epitaxial wafer after the exposure reaction, dissolving the dissolution-resistant layer after the exposure reaction and the photoresist material layer at the bottom thereof, so as to form a preset pattern on the substrate; A metal material is deposited on the surface of the epitaxial wafer forming a preset pattern, and the remaining photoresist material layer is removed to form a metal pattern on the surface of the substrate, completing the photolithography lift-off operation.

2. The microelectronic lithography lift-off processing method according to claim 1, characterized in that: The photoresist material layer further comprises phenolic resin, and the thickness of the photoresist material layer is 0.85 μm-0.9 μm.

3. The microelectronic lithography lift-off processing method according to claim 1, characterized in that: The first developer is AZ300MIF developer, the immersion temperature is 20° C.-25° C., and the immersion time is 60s-120s.

4. The microelectronics photolithography lift-off processing method according to claim 1, characterized in that: After the dissolution-resistant layer is formed on the surface of the photoresist material layer, before the epitaxial wafer soaked in the first developer is subjected to pattern exposure processing according to a preset pattern, the microelectronic lithography lift-off processing method also includes: pre-baking the epitaxial wafer to remove the solvent on the surface of the epitaxial wafer, the pre-baking temperature is 80°C-100°C, and the time is 50s-70s.

5. The microelectronics photolithography lift-off processing method according to claim 1, characterized in that: The step of performing pattern exposure processing on the epitaxial wafer after being soaked in the first developer according to a preset pattern so as to cause an exposure reaction on the dissolution-resistant layer comprises: Placing the epitaxial wafer after the first development immersion on a stage; Arranging an i-line exposure device above an end of the epitaxial wafer away from the substrate for exposure processing; The ultraviolet rays irradiated by the i-line exposure device react with the diazonaphthoquinone photosensitizer in the dissolution-resistant layer to convert the diazonaphthoquinone photosensitizer in the exposure area into a carboxyl group.

6. The microelectronics photolithography lift-off processing method according to claim 5, characterized in that: The second developer is a 2.38% tetramethylammonium hydroxide solution, the developing method is continuous spraying development, the developing temperature is 20° C.-25° C., and the developing time is 90s-120s; The second developer reacts with the carboxyl group converted from the diazonaphthoquinone photosensitizer to generate a product soluble in water.

7. The microelectronics photolithography lift-off processing method according to claim 1, characterized in that: After the exposure reaction occurs on the dissolution-resistant layer and before the development process is performed, the microelectronic lithography lift-off process further includes: performing a post-baking process on the epitaxial wafer, wherein the post-baking temperature is 90° C.-140° C. and the time is 30s-60s.

8. The microelectronics photolithography lift-off processing method according to claim 7, characterized in that: After post-baking and before developing, the microelectronic lithography lift-off method further comprises: flood irradiating the surface of the epitaxial wafer away from the substrate, wherein the exposure intensity of the flood irradiation is 0-75 mJ / cm².

9. A microelectronic device, characterized in that: The microelectronic device is manufactured by using the microelectronic photolithography lift-off processing method according to any one of claims 1 to 8.

Images