Polypeptide chip preparation method and monitoring method for exposure alignment of polypeptide chip

Abstract

The invention discloses a preparation method of a polypeptide chip and a monitoring method for exposure alignment of the polypeptide chip. The monitoring method comprises the following steps: providing a photoresist for preparing a polypeptide chip, dispersing a photochromic substance in the photoresist, and enabling the photochromic substance to be color-changing particles; enabling the photoresist to form a precursor glue film on the surface of a substrate for preparing the polypeptide chip, and carrying out patterning illumination on the precursor glue film; and detecting the color-changing pattern of the precursor glue film, and judging whether the patterning photoetching reaches the standard or not according to the difference between the color-changing pattern and the standard pattern. According to the monitoring method provided by the invention, the photochromic substance is arranged, so that the photoresist precursor film can form color change during patterning illumination, and whether patterning illumination accurately reaches the standard or not can be conveniently monitored according to comparison with a standard pattern; the adverse effect of compound type color-changing substances on the growth of the polypeptide is avoided, so that the exposure alignment monitoring method for the preparation process of the polypeptide chip, which is efficient, convenient and feasible, is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of polypeptide chips, and in particular, to a method for preparing a polypeptide chip and a method for monitoring exposure alignment for a polypeptide chip. Background Art

[0002] A polypeptide chip is fabricated by in-situ solid-phase synthesis of polypeptides on a wafer. First, a photoresist is spin-coated on the wafer surface, and then selectively exposed through a mask under an ultraviolet light device such as a proximity exposure machine. The exposed positions generate photoacid, which in turn initiates the in-situ synthesis of region-selective polypeptide chains. The alignment accuracy of the exposure not only affects the synthesis accuracy of a single layer but also plays a decisive role in the superposition quality of different peptide chain layers.

[0003] The photoresist is a colorless and transparent liquid. After ultraviolet light exposure, it cannot show the characteristics of the selectively exposed areas blocked by the mask, so it is impossible to timely judge the alignment effect. To timely understand the accuracy of the exposure alignment and thereby improve the production efficiency of effective polypeptide chips, it is necessary to add a gateway during the exposure process to make a timely response.

[0004] A photochromic agent (or photo-responsive agent) is a type of substance that can change color under light irradiation. They can change their molecular structure or electronic form by absorbing light of a specific wavelength, thereby causing a color change. Photochromic agents usually have a highly selective color response and have different color-changing effects for different light sources and illumination conditions, and are widely used in the fields of optics, materials science, chemical sensors, display technology, etc.

[0005] In the prior art, a photochromic agent can be selectively used and dispersed in a photoresist system. After ultraviolet light exposure, the positions blocked by the mask template remain the original color unchanged, and the exposed areas change color under light irradiation. The alignment degree between the exposed areas and the theoretical mask pattern is analyzed through a microscope system. When applied to a polypeptide chip, if it is aligned, it can directly enter the subsequent synthesis process; if not aligned, the wafer can be retracted for corresponding processing.

[0006] For example, Chinese Patent CN 108594607A provides a technical solution for adding a compound-type uV color-changing agent to a photoresist system to monitor whether the patterned exposure is aligned. However, this technical solution is applicable to inorganic semiconductor manufacturing processes. The inventor found that when this technical solution is applied to the preparation of polypeptide chips, the compound-type color-changing agent will have a negative impact on the growth of polypeptides, and even lead to the inability to form effective polypeptide sequences, thereby resulting in chip scrapping or failure.

[0007] Therefore, how to avoid the influence of photochromic agents on the growth of polypeptide chains has become a difficult problem for R & D personnel. Summary of the Invention

[0008] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a method for preparing a polypeptide chip and a method for monitoring the exposure alignment of the polypeptide chip.

[0009] To achieve the foregoing invention purpose, the technical solutions adopted by the present invention include:

[0010] In the first aspect, the present invention provides a method for monitoring the exposure alignment of a polypeptide chip, which includes:

[0011] Providing a photoresist for preparing a polypeptide chip, wherein a photochromic substance is dispersed in the photoresist, and the photochromic substance is a color-changing particle;

[0012] Forming a precursor film on the surface of a substrate for preparing a polypeptide chip with the photoresist, and performing patterned illumination on the precursor film;

[0013] Detecting the color-changing pattern of the precursor film, and determining whether the patterned illumination meets the standard according to the difference between the color-changing pattern and the standard pattern.

[0014] In the second aspect, the present invention further provides a method for preparing a polypeptide chip, which includes:

[0015] Providing a substrate for preparing a polypeptide chip;

[0016] Forming a precursor film on the substrate and performing patterned illumination, and using the above monitoring method to monitor whether the patterned illumination meets the standard;

[0017] For the qualified substrates, initiating the in-situ synthesis of selective polypeptide chains in the exposed areas to obtain a polypeptide chip.

[0018] Based on the above technical solutions, compared with the prior art, the beneficial effects of the present invention at least include:

[0019] The monitoring method provided by the present invention can form a color change in the photoresist precursor film during patterned illumination by setting a photochromic substance, thereby generating a corresponding pattern. It is convenient to monitor whether the patterned illumination is accurately qualified according to the comparison between the pattern and the standard pattern; and by preferably using a particulate color-changing particle as the photochromic substance, the adverse effects of the compound-type photochromic substance in the prior art on polypeptide growth are avoided, thereby providing an efficient, convenient and feasible method for monitoring the exposure alignment in the process of preparing a polypeptide chip.

[0020] The above description is only an overview of the technical solutions of the present invention. In order to enable those skilled in the art to more clearly understand the technical means of the present application and implement it according to the content of the specification, the following is a detailed description with reference to the preferred embodiments of the present invention and the accompanying drawings. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the surface pattern of a polypeptide chip before exposure provided by a typical embodiment of the present invention;

[0022] Figure 2 It is a schematic diagram of the surface pattern of a polypeptide chip after exposure provided by a typical embodiment of the present invention. Detailed implementation manners

[0023] In view of the deficiencies in the prior art, the inventors of this case have proposed the technical solution of the present invention through long-term research and a large number of practices. The following will further explain the technical solution, its implementation process, principle, etc. The present invention aims to provide an online monitoring method that combines a photochromic agent and a photoresist for accurately aligning a polypeptide chip. Its uniqueness lies in obtaining a characteristic pattern with selective area color change by irradiating the photochromic agent with ultraviolet light under the shielding of a mask template, so as to judge whether the alignment before exposure is accurate, and provide an objective basis for timely and accurately judging whether the synthesis process can continue.

[0024] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention. However, the present invention may be practiced in other ways than those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0025] An embodiment of the present invention provides a monitoring method for exposure alignment of a polypeptide chip, which includes the following steps:

[0026] Provide a photoresist for preparing a polypeptide chip, wherein the photoresist is dispersed with a photochromic substance, and the photochromic substance is a color-changing particle;

[0027] Form a precursor film of the photoresist on the surface of a substrate for preparing a polypeptide chip, and perform patterned illumination on the precursor film;

[0028] Detect the color-changing pattern of the precursor film, and determine whether the patterned lithography is qualified according to the difference between the color-changing pattern and a standard pattern.

[0029] In the above technical solution, in order to realize an effective method for monitoring exposure alignment in the process of preparing a polypeptide chip, the following requirements need to be met:

[0030] 1) A suitable photochromic agent. First, select a suitable photochromic agent, which is required to have an irradiation response time not longer than the exposure time of the wafer for a proximity exposure machine; then, the selected photochromic agent can be uniformly dispersed (not limited to dissolution) in the photoresist system, does not chemically react with the photoresist system, and has no negative impact on the photoacid generated after the photoresist is irradiated; finally, the color contrast between the irradiated and unirradiated areas of the selected photochromic agent by the proximity exposure machine is obvious.

[0031] 2) Mask design. Design symmetric patterns around the fixed identification of the wafer corresponding to the mask for subsequent data analysis.

[0032] 3) Microscope system. Observe the matching degree between the contour of the exposed area and the symmetric pattern corresponding to the mask under the microscope system to judge the alignment accuracy.

[0033] 4) Monitoring software. Design software to transmit the data of the microscope system to the computer in real time, and observe and analyze the alignment accuracy through the display screen.

[0034] The above requirements belong to the common requirements for exposure alignment monitoring through photochromic substances. However, the requirements of the technical solution provided by the embodiments of the present invention are not limited to this. The inventors of the present invention found that although the conventional compound type color-changing agents have better color-changing performance and are sufficient to produce good effects when applied to inorganic chips such as semiconductor chips, for polypeptide chips, since polypeptide growth is required, most compounds have a negative impact on the solid-phase reaction of amino acids. Therefore, for polypeptide chips, the required photochromic agent is also required not to have a significant adverse effect on the growth of polypeptide chains.

[0035] Therefore, the difference between the present invention and the existing alignment monitoring in the semiconductor field lies in the selection of particulate color-changing agents for color-changing reactions. The color-changing agent is physically dispersed rather than dissolved in the photoresist, and no chemical influence is generated on the outside during the internal color-changing reaction, so it will not affect the growth of polypeptide chains.

[0036] In some embodiments, the mass fraction of the photochromic substance in the photoresist is about 0.1, such as 0.05 - 0.5%.

[0037] In some embodiments, the color-changing particles include any one or a combination of two or more of encapsulated color-changing particles or loaded color-changing particles. The specific selection of color-changing particles is, for example, a kind of photochromic microcapsule, such as a preparation method of urea-formaldehyde photochromic microcapsule and the urea-formaldehyde photochromic microcapsule. The specific preparation process is, for example: generating a urea-formaldehyde prepolymer by polymerizing urea and formaldehyde; through in-situ polymerization, the prepolymer polymerizes and coats the photochromic compound at the water-oil interface to form a urea-formaldehyde photochromic microcapsule. Using the photochromic compound as the core material and urea-formaldehyde resin as the wall material to prepare the photochromic microcapsule.

[0038] Or dissolving the photochromic material in an organic solvent to obtain a photochromic solution; completely dissolving the emulsifier and then adding the photochromic solution, emulsifying the blend solution to obtain an emulsion; adding a resin prepolymer to the emulsion, then adding a dispersant, washing and drying to make the prepolymer wrap the photochromic material to obtain a photochromic microcapsule product.

[0039] In the above method, by coating a layer of shell that has no significant impact on the growth of polypeptides on the surface of the photochromic material, the influence of the compound photochromic agent on the growth of polypeptides is avoided.

[0040] Similarly, for the supported photochromic agent, through cross-linking reaction or the action of a coupling agent, the photochromic agent is tightly bound to the surface of the inorganic particles, and its color-changing reaction is also limited to the surface without causing changes in the large environment, thus having no significant impact on the growth of polypeptides. However, since after all the photochromic agent still has the opportunity to contact the polypeptides, the achieved effect is inferior to that of the encapsulated color-changing particles.

[0041] How to obtain the color-changing particles corresponding to the lithography wavelength is not the core technical means of the present invention. The relevant color-changing particles can be prepared by a self-made method or directly purchased as existing commercial finished color-changing particles.

[0042] In some embodiments, a patterned mask is used for the patterned light irradiation; the light source used for the patterned light irradiation is an ultraviolet light source.

[0043] In some embodiments, a fixed mark is provided on the surface of the substrate, and exposure positions corresponding to the positions around the fixed mark are provided in the patterned mask;

[0044] The monitoring method specifically includes:

[0045] After the patterned light irradiation, the relative positions of the color-changing points generated on the surface area of the precursor film corresponding to the exposure positions are detected by a microscope, and the deviation of the patterned exposure is determined based on the relative positions.

[0046] In some embodiments, a plurality of exposure positions are provided, and the plurality of exposure positions are symmetrically distributed with the corresponding position of the fixed mark as the symmetry point.

[0047] In some embodiments, the fixed mark is in a cross shape, and the plurality of exposure positions are mirror-symmetrically distributed with the two axes of the cross shape as the symmetry axes respectively.

[0048] In some embodiments, when the plurality of color-changing points are symmetrically distributed with the fixed mark and no color change occurs in the unirradiated position of the patterned light irradiation, it is determined that the patterned light irradiation is aligned;

[0049] In some embodiments, when the plurality of color-changing points are asymmetrically distributed around the fixed mark and no color change occurs in the unirradiated position of the patterned light irradiation, it is determined that the patterned light irradiation is offset, and it is determined whether the offset amount is within the standard value. When the offset amount is within the standard value, it is determined that the patterned light irradiation is qualified;

[0050] In some embodiments, when color change occurs at the unexposed positions of the patterned light illumination, it is determined that the patterned mask fails.

[0051] As some typical application examples of the above technical solution, the above technical solution can be implemented by the following specific steps:

[0052] S1: Mask design; (refer to but not limited to Figure 1 the pattern design shown);

[0053] S2: Disperse the photochromic agent in the photoresist system at a mass percentage of 0.1%.

[0054] S3: Spin-coat the new mixed system on the surface of the wafer.

[0055] S4: Proximity exposure machine + mask exposure;

[0056] S5: Compare the dimensions on the micrograph with the mask pattern dimensions to analyze the accuracy of the exposure alignment.

[0057] As a further application of the above technical solution, the embodiment of the present invention also provides a method for preparing a polypeptide chip, which includes the following steps:

[0058] Provide a substrate for preparing a polypeptide chip;

[0059] Form a precursor film on the substrate and perform patterned light illumination, and use the monitoring method provided in any of the above embodiments to monitor whether the patterned light illumination meets the standard;

[0060] For the qualified substrate, initiate the in-situ synthesis of selective polypeptide chains in the exposed area to obtain a polypeptide chip.

[0061] In some embodiments, the preparation method may specifically include:

[0062] Contact the exposed area with a polypeptide chain precursor to form a peptide chain reaction and grow a regionalized polypeptide chain distribution.

[0063] The technical solution of the present invention will be further described in detail below through several embodiments in conjunction with the accompanying drawings. However, the selected embodiments are only used to illustrate the present invention and do not limit the scope of the present invention. In addition, unless otherwise specified, the materials, process equipment, etc. selected in the following embodiments are all from conventional commercial purchases or existing conventional growth schemes.

[0064] Example 1

[0065] The photosensitive color-changing microcapsules are uniformly dispersed in the photoresist system at a mass ratio of 0.1%, and are uniformly distributed on the surface of the wafer by spin coating. After pre-curing baking, it is placed under a proximity exposure machine (or ultraviolet lamp) and exposed through a mask for 3 to 20 seconds. Observe through a microscope system whether the state of the area corresponding to the mask design pattern around the fixed mark on the wafer is symmetric about the fixed mark on the wafer, whether the exposed area changes color significantly, and whether the unexposed area does not change color.

[0066] If the exposed color-changing pattern is symmetric about the fixed mark on the wafer and the masked position of the mask does not change color, the exposure alignment effect is good, and the subsequent process flow can be continued; if the exposed color-changing pattern is asymmetric about the fixed mark on the wafer and the masked position of the mask does not change color, there is a problem of exposure deviation, and it can be determined whether to continue the subsequent process flow according to the actual quality control standard; if the masked position of the mask changes color, the subsequent process flow should not be entered, and the reason for the failure of the mask to block needs to be considered. For wafers with poor alignment effect that cannot continue the subsequent process flow, the wafers need to be returned for rework or otherwise processed.

[0067] Example 2

[0068] In this example, the monitoring method of Example 1 is used for the preparation of the polypeptide chip, and the specific process is as follows:

[0069] The exposed area is contacted with the polypeptide chain precursor to form a peptide chain reaction, and a regionalized polypeptide chain distribution is grown, and a polypeptide chip with better performance can be obtained after growth.

[0070] Example 3

[0071] This example is generally similar to Example 1, and the only difference is that:

[0072] Replace with a kind of supported color-changing microparticle, and its structure is to load the same organic color-changing material on the surface of titanium dioxide at the scale of hundreds of nanometers through a silane coupling agent.

[0073] Effective alignment monitoring and polypeptide chip growth can still be achieved, but the uniformity of the chips obtained by growth is inferior to that of Example 2.

[0074] Comparative Example 1

[0075] This comparative example is generally the same as Examples 1 and 2. The main difference is that instead of providing capsule-type photochromic microparticles, the photochromic organic components are directly added to the photoresist in equal doses.

[0076] Finally, when using the method of Example 2 for polypeptide growth, a polypeptide chip sufficient for application cannot be obtained at all, and only a small amount of regions have successfully grown polypeptides.

[0077] Therefore, simply imitating the color-changing alignment method in the existing semiconductor process is difficult to avoid affecting the polypeptide during the growth of the polypeptide chip. It is necessary to combine corresponding blocking means to successfully achieve alignment monitoring and polypeptide growth simultaneously.

[0078] Based on the above embodiments and comparative examples, it can be clearly seen that the monitoring method provided by the embodiments of the present invention can form a color change in the photoresist precursor film when patterned illumination is performed by setting a photochromic substance, thereby generating a corresponding pattern. According to the comparison between the pattern and the standard pattern, it is convenient to monitor whether the patterned illumination meets the standard accurately; and by preferably using particulate color-changing microparticles as the photochromic substance, the adverse effects of the compound-type color-changing substance in the prior art on polypeptide growth are avoided, thus providing an efficient, convenient and feasible exposure alignment monitoring method for the preparation process of polypeptide chips.

[0079] It should be understood that the above embodiments are only used to illustrate the technical concept and characteristics of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A monitoring method for polypeptide chip exposure alignment, characterized in that, Comprising: Providing a photoresist for preparing a polypeptide chip, wherein a photochromic substance is dispersed in the photoresist, and the photochromic substance is a color-changing particle; Forming a precursor film on the surface of a substrate for preparing a polypeptide chip with the photoresist, and performing patterned illumination on the precursor film; Detecting the color-changing pattern of the precursor film, and judging whether the patterned lithography is qualified according to the difference between the color-changing pattern and a standard pattern.

2. The monitoring method according to claim 1, wherein The mass fraction of the photochromic substance in the photoresist is 0.05-0.5%.

3. The monitoring method according to claim 1, characterized in that The color-changing particles include any one or a combination of two of encapsulated color-changing particles and supported color-changing particles; Wherein, the structure of the encapsulated color-changing particles is that a transparent shell encapsulates a color-changing chemical substance, and the structure of the supported color-changing particles is that a color-changing material is supported on the surface of an inorganic particle carrier through a chemical bond.

4. The monitoring method according to claim 1, wherein Performing the patterned illumination with a patterned mask; the light source used for the patterned illumination is an ultraviolet light source.

5. The monitoring method according to claim 4, characterized in that, A fixed mark is arranged on the surface of the substrate, and exposure positions corresponding to the positions around the fixed mark are arranged in the patterned mask; The monitoring method specifically includes: After performing the patterned illumination, detecting the relative position between the color-changing points generated on the surface area of the precursor film corresponding to the exposure positions and the fixed mark through a microscope, and judging the offset situation of the patterned exposure based on the relative position.

6. The monitoring method according to claim 5, wherein A plurality of the exposure positions are arranged, and the plurality of exposure positions are symmetrically distributed with the corresponding position of the fixed mark as the symmetry point.

7. The monitoring method according to claim 6, wherein, The fixed mark is in a cross shape, and the plurality of exposure positions are mirror-symmetrically distributed with the two axes of the cross shape as the symmetry axes respectively.

8. The monitoring method according to claim 6 or 7, characterized in that When the plurality of color-changing points are symmetrically distributed with the fixed mark and no color change occurs in the unexposed position of the patterned illumination, it is judged that the patterned illumination is aligned; And / or, when the plurality of color-changing points are asymmetrically distributed around the fixed mark and no color change occurs in the unexposed position of the patterned illumination, it is judged that the patterned illumination is offset, and it is determined whether the offset amount is within a standard value. When the offset amount is within the standard value, it is judged that the patterned illumination is qualified; And / or, when color change occurs in the unexposed position of the patterned illumination, it is judged that the patterned mask fails.

9. A method for preparing a polypeptide chip, characterized in that, Comprising: Providing a substrate for preparing a polypeptide chip; Forming a precursor film on the substrate and performing patterned illumination, and monitoring whether the patterned illumination is qualified by using the monitoring method according to any one of claims 1-8; For the qualified substrate, initiating the in-situ synthesis of selective polypeptide chains in the exposed area to obtain a polypeptide chip.

10. The preparation method according to claim 9, characterized in that, Specifically including: Bringing the exposed area into contact with a polypeptide chain precursor to form a peptide chain reaction and grow a regionalized polypeptide chain distribution.

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