Thinning and polishing treatment method suitable for photoresist and micro-nano device

Abstract

The invention discloses a thinning and polishing treatment method suitable for photoresist and a micro-nano device. The method comprises the following steps: spin-coating the photoresist capable of realizing an extremely high aspect ratio on a substrate, and curing the photoresist; performing form finishing on the surface of the photoresist by adopting a low-pressure and low-rotating-speed CMP (Chemical Mechanical Polishing) technology, so that the height difference of the surface of the photoresist is less than 5 microns; carrying out rough polishing by adopting a high-pressure and high-rotation CMP (Chemical Mechanical Polishing) technology to polish the surface of the photoresist to a preset thickness; the processed photoresist is cleaned, and then the photoresist is cleaned; compared with a dry etching method in the prior art, the problems of low speed, large roughness and poor uniformity can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of photoresist thinning and polishing processing, and in particular relates to a thinning and polishing processing method suitable for photoresist and a micro-nano device. Background Art

[0002] Photoresist, also known as photoresist, refers to a thin film material that changes its solubility through exposure or radiation of ultraviolet light, electron beam, ion beam, X-ray, etc. It can be used for etching and electroplating of different materials, is suitable for high aspect ratio processes, has high transparency, good verticality, and is widely used in the preparation of micro-nano devices; however, due to the difficulty of removing the photoresist, its application is limited. The current main treatment method is to thin it to a certain thickness to act as a dielectric layer without affecting the subsequent processes.

[0003] In the related technology, the method of thinning and polishing the photoresist on the substrate surface mainly relies on dry etching. Commonly used etching equipment mainly includes ICP (plasma etching) RIE (reactive ion etching) IBE (ion beam etching), etc. ICP and RIE equipment mainly use fluorine-based gas and oxygen to carry out reactive ion etching, but their etching rate is slow. At the same time, the surface height difference after etching is more than 2um. The energy accumulation during the etching process is prone to denaturation of the photoresist and etching stops; while IBE uses a single argon ion bombardment surface removal rate that is slower than ICP / RIE, but the height difference after etching is smaller. In other words, the current mainstream etching method has the disadvantages of long etching time and large height difference after etching, which limits the photoresist thinning and polishing process and greatly limits the application of high aspect ratio photoresists.

[0004] Therefore, the above-mentioned current mainstream etching methods have disadvantages such as long etching time and large height difference after etching, which leads to limited photoresist thinning and polishing process and greatly restricts the technical problems and defects of the application of high aspect ratio photoresist. It is urgent to design and develop a thinning and polishing method suitable for photoresist. Summary of the invention

[0005] In order to overcome the deficiencies and difficulties of the above-mentioned prior art, the purpose of the present invention is to provide a thinning and polishing method suitable for photoresist and a micro-nano device; aiming to solve the problem of thinning and polishing process of photoresist with extremely high aspect ratio.

[0006] The first object of the present invention is to provide a thinning and polishing method suitable for photoresist; the second object of the present invention is to provide a micro-nano device.

[0007] The first object of the present invention is achieved in that the method comprises:

[0008] Spin coating a photoresist capable of achieving an extremely high aspect ratio on a substrate, and curing the photoresist;

[0009] Using low-pressure and low-speed CMP technology to perform morphological trimming on the surface of the photoresist so that the height difference of the surface of the photoresist is less than 5 μm;

[0010] A high-pressure and high-speed CMP technique is used for rough polishing to grind the surface of the photoresist to a preset thickness;

[0011] The processed photoresist is cleaned.

[0012] Furthermore, the method of curing the photoresist comprises the following steps:

[0013] Performing a pre-exposure baking process on the photoresist;

[0014] Expose the baked photoresist using a mask and a preset exposure dose, and then transfer the pattern on the mask to the surface of the substrate using a developer;

[0015] The developed substrate is post-baked and the photoresist is cured.

[0016] Furthermore, the baking temperature of the pre-exposure baking treatment is 65° C. to 120° C., and the time is 30 min to 90 min.

[0017] Furthermore, the post-baking has a baking temperature of 90° C. to 120° C. and a time of 10 min to 30 min. Preferably, the post-baking has a baking temperature of 90° C. and a time of 30 min.

[0018] Furthermore, in the morphology finishing, the rough polishing pressure is 2psi; the polishing liquid flow rate is 220ml / min; the polishing disc speed is 93R / min, and the polishing head speed is 87R / min; the polishing rate is 4um; the polishing liquid is an aluminum oxide polishing liquid, and the abrasive particle size is 1um.

[0019] Furthermore, the height difference of the surface of the photoresist after morphology trimming is less than 3 μm.

[0020] Furthermore, the polishing pressure in the thinning polishing process is 1.5psi~2psi; the polishing liquid flow rate is 90ml / min~220mL / min; the polishing disc speed is 63R / min~93R / min, the polishing head speed is 60R / min~87R / min; the polishing rate is 4um-200um.

[0021] Furthermore, after morphological modification, the photoresist was thinned and rough-polished over a large area, wherein the polishing pressure was 2 psi; the polishing liquid flow rate was 120 mL / min; the polishing disc speed was 93 R / min, the polishing head speed was 87 R / min; and the polishing rate was 4 um;

[0022] The polishing liquid is an aluminum oxide polishing liquid, and the abrasive particle size is 1 um.

[0023] Furthermore, before cleaning the processed photoresist, the method further comprises the following steps: fine polishing the surface of the photoresist;

[0024] The polishing pressure of the fine polishing is 1.5psi; the polishing liquid flow rate is 120mL / min; the polishing disc speed is 63R / min, and the polishing head speed is 60R / min; the polishing rate is 200um; the polishing liquid is a silica sol polishing liquid with an abrasive particle size of 80um.

[0025] The second object of the present invention is achieved in this way: the micro-nano device is processed by the thinning and polishing method suitable for photoresist;

[0026] The micro-nano device utilizes photoresist thinning and polishing to partially expose the metal circuit, and part of the photoresist needs to be retained for the dielectric layer support process.

[0027] The present invention can realize a photoresist with an extremely high aspect ratio by spin coating on a substrate and solidifying the photoresist; adopts a low-pressure and low-speed CMP technology to perform morphological trimming on the surface of the photoresist so that the height difference of the surface of the photoresist is less than 5μm; adopts a high-pressure and high-speed CMP technology to perform rough polishing to grind the surface of the photoresist to a preset thickness; and cleans the processed photoresist; compared with the dry etching method in the related art, the present invention can effectively solve the problems of slow rate, large roughness and poor uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A schematic flow chart of a thinning and polishing method for photoresist according to the present invention;

[0030] Figure 2 A schematic diagram of a preparation process of an embodiment of a method for thinning and polishing photoresist according to the present invention;

[0031] Figure 3 The present invention is a schematic diagram of a second preparation process of an embodiment of a method for thinning and polishing photoresist suitable for use in the present invention. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the purpose, technical solutions and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. Those skilled in the art can easily understand other advantages and functions of the present invention from the contents disclosed in this specification; however, the present invention can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] As described in the background technology section, traditional etching methods have disadvantages such as long etching time and large height difference after etching, which limits the photoresist thinning and polishing process and greatly restricts the application of high aspect ratio photoresists.

[0035] In view of this, if Figure 1-Figure 3 As shown, the present invention provides a thinning and polishing method suitable for photoresist, the method comprising:

[0036] S01. Spin-coat a photoresist capable of achieving an extremely high aspect ratio on a substrate, and cure the photoresist; specifically, the substrate is generally made of silicon, quartz or other required materials, and the substrate should be cleaned according to actual needs before use. Photoresists capable of achieving an extremely high aspect ratio generally refer to photoresists made of materials such as SU8, PI, THB, etc., and their specific use can be selected according to actual conditions.

[0037] The photoresist can be coated by spin coating or spray coating, preferably by spin coating. After the photoresist coating is completed, the photoresist should be cured. According to the actual properties and requirements of the photoresist, the curing operation of the photoresist can be adjusted according to the actual situation, and is not specifically limited here.

[0038] When SU8 and PI are selected as photoresists, the preferred curing steps are as follows:

[0039] ① Spin coating on a clean substrate can achieve a photoresist with an extremely high aspect ratio, that is, spinning on a clean silicon / quartz substrate (such as SU8 / PI, etc.) can achieve a photoresist with an extremely high aspect ratio. A heating table is used for baking before exposure. The working temperature is adjusted according to the material and thickness, generally 65℃-120℃, and the time is 30min-90min. Then the mask exposure can be performed according to actual needs; a designed mask is used for exposure, and then an adapted developer is used to transfer the pattern to the substrate surface.

[0040] ② After the mask is exposed, post-exposure baking can be carried out on a heating table, that is, appropriate heat treatment is taken on the developed substrate to remove residual water vapor and volatile organic matter on the surface; the working temperature is generally selected at 90℃-120℃, and the time is 10min-30min, so that the photoresist is completely cured.

[0041] The mask exposure method is as follows: a designed mask is used to perform exposure work at an appropriate exposure dose, and then a suitable developer is used to perform development work to transfer the designed pattern on the mask to the substrate surface.

[0042] S02. Use low-pressure and low-speed CMP technology to shape the surface of the photoresist so that the height difference of the surface of the photoresist is less than 5μm; this shape trimming method is achieved through a low-pressure and low-speed CMP grinding process, and the surface of the photoresist is morphologically trimmed to avoid large fluctuations and defects on the surface of the photoresist, overcoming the problem that the existing conventional photoresist coating method is prone to cause large surface height differences, and the upper CMP machine is prone to generate large friction resistance during operation, resulting in easy fragmentation. That is, select the appropriate working disk and polishing head speed, as well as the appropriate pressure, and properly match the polishing pad under a certain polishing liquid flow rate to perform polishing and thinning of the photoresist to achieve the desired thickness and roughness.

[0043] Among them, low pressure and low speed are used for morphology trimming, and the specific method is: install the substrate on the CMP equipment, vacuum polish it through the black airbag silicone pad, and set the main polishing parameter pressure to 1.5psi~2psi, the polishing liquid flow rate to 90mL / min~220mL / min, the polishing disk speed to 63R / min-93R / min, and the polishing head speed to 60R / min~87R / min.

[0044] Among them, the material, polishing pressure and rotation speed of the above-mentioned polishing pad can be adjusted according to actual needs to achieve a surface height difference of less than 5 microns and no fragments will appear during the CMP polishing process, that is, low pressure and low rotation speed are first used to evenly coat the photoresist on the substrate surface, and then the height difference is large and trimmed to achieve a basically flat photoresist surface with a height difference of <1um-5um.

[0045] Preferably, the surface of the photoresist after morphology modification can be substantially flat, and the height difference is maintained between 1 micron and 5 microns. More preferably, the height of the photoresist should be less than 3 microns.

[0046] S03. The substrate after surface trimming is rough polished by high pressure and high speed CMP technology to remove large-area surface defects of the photoresist and the actual removal thickness, so that the photoresist can reach a preset thickness. The specific method of the rough polishing process is: the rough polishing pad uses double-layer polyurethane, the polishing liquid uses alumina polishing liquid, the abrasive particle size is 1um, the thinning polishing pressure data is 2.0psi; the polishing liquid flow data is 220ml / min, the polishing disc speed data is 93R / min; the polishing head speed data is 87R / min.

[0047] Among them, the material, polishing pressure and rotation speed of the above-mentioned polishing pad can be adjusted according to actual needs to meet the requirements of rapid polishing to a preset thickness.

[0048] According to actual needs, if there is a higher requirement for the flatness of the treated photoresist surface, fine polishing can be further performed to improve the roughness and flattening. Preferably, the fine polishing process can be referred to as follows: the fine polishing pad uses black damping cloth, the light liquid selects silica sol, the polishing liquid abrasive particle size is 80nm, the thinning polishing pressure data is 1.5psi, the polishing liquid flow data is 120ml / min, the polishing disc speed data is 63R / min, and the polishing head speed data is 60R / min.

[0049] The specific parameter selection can be adjusted according to the actual situation and the required flatness, and no specific limitation is made here.

[0050] S04, cleaning the processed photoresist. A post-CMP cleaning machine is used to directly clean the surface of the photoresist to remove the debris remaining on the surface and ensure the smoothness of the surface.

[0051] CMP technology is generally a grinding and polishing device. The present application innovatively uses CMP technology to thin and polish photoresist. Compared with the conventional thinning method in the prior art, it has the effect of fast thinning speed and better thinning uniformity.

[0052] In the prior art, since CMP technology is generally used to polish hard metal materials, directly polishing photoresist with CMP technology is prone to extremely large friction resistance, thereby causing the entire substrate to break. The present application avoids the problem of fragmentation by pre-trimming the surface morphology of the photoresist and controlling the CMP parameters, and can ensure the uniformity of the thickness of the entire photoresist surface.

[0053] The advantages and technical effects of the photoresist thinning and polishing preparation method of the embodiment of the present invention are as follows: the CMP thinning and polishing photoresist preparation method can effectively solve the problems of slow rate, large roughness, and poor uniformity compared to the dry etching method in the related art. Moreover, the preparation process of the embodiment of the present invention is stable, the process time is short, the personnel efficiency is high, a variety of different structures can be used at low cost, and the production efficiency is high, which can effectively ensure that the preparation of photoresist thinning and polishing is completed at a relatively low cost; and the production process has no harmful substances discharged, which is green and environmentally friendly.

[0054] Example 1

[0055] The present invention provides a method for polishing and thinning a photoresist, comprising the following steps:

[0056] S1. Preparation of photoresist: Spread the photoresist on a clean silicon / quartz substrate (such as SU8 / PI, etc.) using a photoresist machine to achieve extremely high aspect ratio. Use a heating table for pre-exposure baking at a working temperature of 65℃~105℃ for 30min~60min.

[0057] S2. Exposure for SU8 / PI and other photoresists that can achieve extremely high aspect ratios, using a designed mask to perform exposure work at an appropriate exposure dose;

[0058] S3, after development, using an adapted developer to carry out development work to transfer the pattern designed on the mask to the substrate surface;

[0059] S4. Post-baking: Select a post-baking temperature of 90°C to 120°C and a time of 10min to 30min to cure the photoresist.

[0060] S5. Sample loading: Manually load the sample into the fixture of the polishing head, and the equipment uses a black airbag silicone pad for vacuum adsorption. Polishing liquid transmission method: Open the outer packaging of the suitable polishing liquid and transfer it to the polishing pad position through the peristaltic pump soft pipe. Set the peristaltic pump polishing liquid flow rate to 220ml / min.

[0061] S6. Equipment parameter setting and operation: Turn on the equipment power, mechanical pump, gas, select the photoresist polishing program to set the parameters. The pressure of the main polishing parameters is 1.5psi~2psi, the polishing disc speed is 88R / min~93R / min, and the polishing head speed is 87R / min. Perform rough polishing, thinning to the required thickness, replace the silica sol polishing liquid. The abrasive particle size is generally around 80nm, the pressure is 1.5PSI, the polishing liquid flow rate is 120ml / min, the polishing disc speed is 63R / min, and the polishing head speed is 60R / min. Perform fine polishing to improve the roughness and flatness of the substrate surface and reduce the step difference. Thickness monitoring: Some CMP equipment has terminal detection and monitoring functions, and the actual removal thickness and rate are tested with a step meter.

[0062] S7, end of thinning and polishing: After thinning and polishing, the wafer source needs to be cleaned with a post-CMP cleaning machine. The specific residual pollution can be cleaned with a wet organic solution according to the actual residue. Clean the polishing pad, polishing head and polishing disc inside the workbench, the peristaltic pump pipeline, the polishing pad needs to be moisturized, and the power of the equipment and the mechanical pump and other gases are turned off.

[0063] Table 1: Glue thickness before thinning and polishing and after thinning and polishing, different parameters and rates in the preparation method of Example 1

[0064]

[0065] The thickness and roughness of the photoresist after thinning and polishing prepared by the preparation method of test example 1 were tested at least at 10 different positions on the same photoresist surface. The results showed that the thickness was within the range of 35um±20nm, the error between the actual thickness value and the target thickness of 35um was small, and the roughness at 10 different positions was within 1nm±1nm, indicating that the photoresist prepared by the preparation method of example 1 had good uniformity, high flatness and low roughness.

[0066] In addition, by observing the appearance of the photoresist prepared by the preparation method of Example 1, no appearance defects such as orange peel, breakage, burrs, etc. were found.

[0067] Example 2

[0068] On the basis of the above-mentioned embodiment 1, in step S1, the substrate is a silicon wafer, the photoresist is SU8 negative photoresist, the thickness is 70um, the pre-baking temperature is 65℃, and the time is 30min. In step S2, the designed mask is used to expose the photoresist surface using a photolithography machine, and the developer is immersed for graphic transfer. In step S3, the substrate after development is post-baked at 90℃; the time is 10min. In step S4, the rough polishing pad in the CMP equipment uses double-layer polyurethane, the polishing liquid uses alumina polishing liquid with a large abrasive particle size of generally about 1um, the pressure is 2Psi polishing liquid 220ml / min, the polishing disc speed is 93R / min; the polishing head speed is 87R / min. The fine polishing pad in the CMP equipment uses black damping cloth, the polishing liquid uses silica sol polishing liquid with abrasive particle size generally around 80nm, the pressure is 1.5psi, the polishing liquid flow rate is 120ml / min, the polishing disc speed is 63R / min, and the polishing head speed is 60R / min. The rough polishing rate is 4um / min, and the fine polishing rate is 200nm / min. The actual thinning thickness is 35um~40um. In step S5, the height difference of the substrate surface after the photoresist is evenly coated is first trimmed by low pressure and low speed. The height difference of the surface of the photoresist after morphological trimming is less than 4μm; in step S6, the substrate with the pre-trimmed photoresist surface is rough-polished with a high-pressure and high-speed rough polishing pad to remove large-area photoresist surface defects and actual removal thickness. Use a fine polishing pad to select appropriate pressure and speed polishing liquid flow to fine-polish the photoresist surface, improve roughness and flattening, and use a CMP post-cleaning machine for cleaning after completion; compared with the preparation method using the related art, the photoresist surface morphology of the thinned and polished photoresist of the present invention is better, the rate is fast, the flatness is high, the uniformity is good, and there are no obvious appearance defects.

[0069] Example 3

[0070] On the basis of the above-mentioned embodiment 1, in step S1, the substrate is a silicon wafer, the photoresist is SU8 negative photoresist, the thickness is 70um, the pre-baking temperature is 120℃, and the time is 90min. In step S2, the designed mask is used to expose the photoresist surface using a photolithography machine, and the developer is immersed for graphic transfer. In step S3, the substrate after development is post-baked at 90℃; the time is 30min. In step S4, the rough polishing pad in the CMP equipment uses double-layer polyurethane, the polishing liquid uses alumina polishing liquid with a large abrasive particle size of generally about 1um, the pressure is 2psi, the polishing liquid flow rate is 90ml / min, the polishing disc speed is 63R / min; the polishing head speed is 60R / min. The fine polishing pad in the CMP equipment uses black damping cloth, the polishing liquid uses silica sol polishing liquid with abrasive particle size generally around 80nm, the pressure is 2psi, the polishing liquid flow rate is 90ml / min, the polishing disc speed is 93R / min; the polishing head speed is 60R / min. The rough polishing rate is 4um / min, and the fine polishing rate is 200nm / min. The actual thinning thickness is 35um. In step S5, the height difference of the substrate surface after the photoresist is evenly coated is first trimmed by low pressure and low speed. The height difference of the surface of the photoresist after morphological trimming is less than 1μm; in step S6, the substrate with the pre-trimmed photoresist surface is rough-polished with a high-pressure and high-speed rough polishing pad to remove large-area photoresist surface defects and actual removal thickness. Use a fine polishing pad to select appropriate pressure and speed polishing liquid flow to fine-polish the photoresist surface, improve roughness and flattening, and use a CMP post-cleaning machine for cleaning after completion; compared with the preparation method in the related art, the photoresist surface morphology of the thinned and polished photoresist of the present invention is better, the rate is fast, the flatness is high, the uniformity is good, and there are no obvious appearance defects.

[0071] Example 4

[0072] On the basis of the above-mentioned embodiment 1, in step S1, the substrate is a silicon wafer, the photoresist is SU8 negative photoresist, the thickness is 70um, the pre-baking temperature is 100℃, and the time is 80min. In step S2, the designed mask is used to expose the photoresist surface using a photolithography machine, and the developer is immersed for graphic transfer. In step S3, the substrate after development is post-baked at 70℃; the time is 20min. In step S4, the rough polishing pad in the CMP equipment uses double-layer polyurethane, the polishing liquid uses alumina polishing liquid with a large abrasive particle size of generally about 1um, the pressure is 1.8psi, the polishing liquid flow rate is 120ml / min, the polishing disc speed is 75R / min; the polishing head speed is 70R / min. The fine polishing pad in the CMP equipment uses black damping cloth, the polishing liquid uses silica sol polishing liquid with abrasive particle size generally around 80nm, the pressure is 1.5psi, the polishing liquid flow rate is 100ml / min, the polishing disc speed is 83R / min; the polishing head speed is 70R / min. In step (4), the rough polishing rate is 5um / min, and the fine polishing rate is 150nm / min. The actual thinning thickness is 40um. In step S5, the height difference of the photoresist on the substrate surface after the photoresist is evenly coated is first trimmed by low pressure and low speed, and the height difference of the surface of the photoresist after the morphological trimming is less than 4μm; in step S6, the substrate with the pre-trimmed photoresist surface is rough-polished with a high-pressure and high-speed rough polishing pad to remove large-area photoresist surface defects and actual removal thickness. Use a fine polishing pad to select appropriate pressure and speed polishing liquid flow to fine-polish the photoresist surface, improve roughness and flattening, and use a CMP post-cleaning machine for cleaning after completion; compared with the preparation method using the related art, the photoresist surface morphology of the thinned and polished photoresist of the present invention is better, the rate is fast, the flatness is high, the uniformity is good, and there are no obvious appearance defects.

[0073] In view of the technical defects of the existing etching methods, such as long etching time and large height difference after etching, which leads to the limitation of photoresist thinning and polishing process, and greatly limits the application of high aspect ratio photoresist, the photoresist thinning and polishing process mainly relies on dry etching on the substrate surface, such as: commonly used etching equipment mainly includes ICP (plasma etching) RIE (reactive ion etching) IBE (ion beam etching), etc. ICP and RIE equipment mainly use fluorine-based gas and oxygen to carry out reactive ion etching, and the traditional method has a slow etching rate, and the surface height difference after etching is more than 2um, and the energy stacking in the etching process is easy to cause photoresist denaturation and etching to stop; and IBE uses a single argon ion bombardment surface removal rate that is slower than ICP / RIE, and the height difference after etching is smaller. Specifically, the traditional process thinning and polishing process: chemical mechanical polishing (its process is quite complicated and there are many influencing factors); for those skilled in the art, they will set or modify parameters based on traditional etching equipment (such as simplifying the operation process and reducing process influencing factors).

[0074] In addition, because the photoresist coating method can easily lead to large surface height differences, the CMP machine can easily generate large friction resistance during operation, which can lead to easy fragmentation. It is necessary to strictly control the uniformity and height difference of the coating, and adjust the time, speed, and amount of the coating machine to reduce the degree of large differences in the surface height of the substrate photoresist.

[0075] That is to say, it is not easy for those skilled in the art to use CMP technology and specific technical parameters to thin and polish photoresist, compared with several traditional preparation methods. Through the scheme of the present invention, the method of using CMP to thin and polish photoresist has a better removal rate and extremely high depth-width selectivity process application. In other words, it is difficult to think of using silica sol polishing liquid with alkaline abrasive particles of small size, low pressure and low speed to improve the morphology of photoresist on the substrate surface and reduce the roughness and flatness, and reduce the step difference between the photoresist and the substrate material structure.

[0076] To achieve the purpose of the present invention, the present invention also provides a micro-nano device, which is applied to the thinning and polishing method suitable for photoresist; the micro-nano device uses photoresist thinning and polishing to make part of the metal circuit leak out, and part of the photoresist needs to be retained as a dielectric layer support process.

[0077] That is to say, the embodiment of the present invention also provides a micro-nano device that uses photoresist polishing to thin the metal line so that part of the metal line is leaked, and part of the photoresist needs to be retained as a dielectric layer support process to facilitate the subsequent process. The advantages and technical effects brought by the micro-nano device manufacturing of the embodiment of the present invention are: fast photoresist removal rate, high flatness, and small roughness; it can achieve extremely high aspect ratio process requirements.

[0078] The present invention can realize a photoresist with a very high aspect ratio by spin coating on a substrate, and solidify the photoresist; use a low-pressure and low-speed CMP technology to perform morphological trimming on the surface of the photoresist, so that the height difference of the surface of the photoresist is less than 5μm; use a high-pressure and high-speed CMP technology to perform rough polishing, remove surface defects of the photoresist in a large area and actually remove the thickness; clean the processed photoresist, that is, spin coating the photoresist with a very high aspect ratio on the substrate, and bake the photoresist before exposure; wherein the substrate is a cleaned silicon / quartz substrate; a mask is used and combined with The baked photoresist is exposed with a preset exposure dose, and then the pattern on the mask is transferred to the surface of the substrate using a developer; the substrate after development is heat-treated and the photoresist is cured; then based on polishing parameter data, the photoresist is thinned and polished to a preset thickness and roughness, and a post-CMP cleaning machine is used to complete the cleaning operation; wherein the polishing parameter data includes polishing disc speed data, thinning polishing pressure data, polishing liquid flow data and polishing head speed data; compared with the dry etching method in the related art, the problem of slow rate, large roughness and poor uniformity can be effectively solved.

[0079] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for thinning and polishing a photoresist, characterized in that: The method comprises: Spin coating a photoresist capable of achieving an extremely high aspect ratio on a substrate, and curing the photoresist; Using low-pressure and low-speed CMP technology to perform morphological trimming on the surface of the photoresist so that the height difference of the surface of the photoresist is less than 5 μm; A high-pressure and high-speed CMP technique is used for rough polishing to grind the surface of the photoresist to a preset thickness; The processed photoresist is cleaned.

2. A thinning and polishing method suitable for photoresist according to claim 1, characterized in that: The method of curing the photoresist comprises the following steps: Performing a pre-exposure baking process on the photoresist; Expose the baked photoresist using a mask and a preset exposure dose, and then transfer the pattern on the mask to the surface of the substrate using a developer; The developed substrate is post-baked and the photoresist is cured.

3. A thinning and polishing method suitable for photoresist according to claim 2, characterized in that: The baking temperature of the pre-exposure baking treatment is 65° C. to 120° C., and the time is 30 min to 90 min.

4. A thinning and polishing method suitable for photoresist according to claim 2, characterized in that: The post-baking temperature is 90° C. to 120° C., and the time is 10 min to 30 min. Preferably, the post-baking temperature is 90° C., and the time is 30 min.

5. A method for thinning and polishing a photoresist according to any one of claims 1 to 4, characterized in that: In the morphology finishing, the rough polishing pressure is 2psi; the polishing liquid flow rate is 220mL / min; the polishing disc speed is 93R / min, and the polishing head speed is 87R / min; the polishing rate is 4um; the polishing liquid is an aluminum oxide polishing liquid, and the abrasive particle size is 1um.

6. A method for thinning and polishing photoresist according to claim 5, characterized in that: The height difference of the surface of the photoresist after morphology trimming is less than 3 μm.

7. A method for thinning and polishing a photoresist according to any one of claims 1 to 4, characterized in that: After morphology trimming, the photoresist is thinned and roughly polished over a large area, wherein the polishing pressure is 1.5psi~2psi; the polishing liquid flow rate is 90ml / min~220mL / min; the polishing disc speed is 63R / min~93R / min, the polishing head speed is 60R / min~87R / min; the polishing rate is 4um-200um.

8. A thinning and polishing method suitable for photoresist according to claim 7, characterized in that: After morphological modification, the photoresist was thinned and rough polished over a large area, wherein the polishing pressure was 2psi; the polishing liquid flow rate was 120ml / min; the polishing disc speed was 93R / min, the polishing head speed was 87R / min; and the polishing rate was 4um; The polishing liquid is an aluminum oxide polishing liquid, and the abrasive particle size is 1 um.

9. A thinning and polishing method suitable for photoresist according to claim 5, characterized in that: Before cleaning the processed photoresist, the method further comprises the following steps: fine polishing the surface of the photoresist; The polishing pressure of the fine polishing is 1.5psi; the polishing liquid flow rate is 120mL / min; the polishing disc speed is 63R / min, and the polishing head speed is 60R / min; the polishing rate is 200um; the polishing liquid is a silica sol polishing liquid with an abrasive particle size of 80um.

10. A micro-nano device, characterized in that: The micro-nano device is processed by the thinning and polishing method applicable to photoresist as described in any one of claims 1 to 9.

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