阅读说明：本技术 一种光刻胶组合物及其用途 (Photoresist composition and application thereof ) 是由 刁翠梅 李冰 张咪 王双双 陈昕 王文芳 董栋 张宁 于 2021-06-22 设计创作，主要内容包括：本申请提供了一种光刻胶组合物及其用途,该光刻胶组合物,以重量份计,包括以下成分：酚醛树脂10-50份、感光剂1-10份、塑化剂0.1-5份、添加剂0.1-5份和有机溶剂40-100份,添加剂包括结构式(I)所示化合物中的至少一种。将本申请的光刻胶作为G线光刻胶或I线光刻胶使用,具有较低的回流温度,能避免高温对器件造成不利影响,在较低的温度下迅速回流形成形貌良好的微镜阵列,可用于对温度要求苛刻的生产工艺中。而且较小尺寸、或者较大高宽比的图形也能回流成形貌良好的微镜阵列。(The application provides a photoresist composition and an application thereof, wherein the photoresist composition comprises the following components in parts by weight: 10-50 parts of phenolic resin, 1-10 parts of photosensitizer, 0.1-5 parts of plasticizer, 0.1-5 parts of additive and 40-100 parts of organic solvent, wherein the additive comprises at least one of compounds shown in a structural formula (I). The photoresist is used as a G-line photoresist or an I-line photoresist, has lower reflux temperature, can avoid adverse effects on devices caused by high temperature, quickly reflows at lower temperature to form a micromirror array with good appearance, and can be used in a production process with harsh requirements on temperature. And smaller size, or higher aspect ratio patterns can also reflow to form a good looking micromirror array.)

1. The photoresist composition comprises the following components in parts by weight: 10-50 parts of linear phenolic resin, 1-10 parts of photosensitizer, 0.1-5 parts of plasticizer, 0.1-5 parts of additive and 40-100 parts of organic solvent;

the additive comprises at least one of the compounds of formula (I):

wherein R is₁-R₅Each independently selected from hydrogen, halogen atom, hydroxyl group, ether group, ester groupPhenyl, C₁-C₁₀Alkyl of (C)₃-C₁₀A cycloalkyl group of (a), a sulfonic acid group unsubstituted or substituted with Ra, an amino group unsubstituted or substituted with Ra;

each Ra is independently selected from C₆-C₁₀Cycloalkyl or phenyl.

2. The photoresist composition of claim 1, wherein the additive comprises at least one of the following compounds D1-D4:

3. the resist composition according to claim 1, wherein the novolak resin includes at least one of polycondensates obtained by condensation polymerization of cresol compounds and aldehyde compounds,

the cresol compound comprises at least one of m-cresol, p-cresol, o-cresol, xylenol and trimethylphenol,

the aldehyde compound includes at least one of formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and salicylaldehyde.

4. The photoresist composition according to claim 1, wherein the novolac resin comprises a condensation polymer obtained by condensation polymerization of m-cresol and p-cresol with formaldehyde, and the molar ratio of the m-cresol to the p-cresol is 1:1 to 1:4, preferably 1:1 to 1: 2.5.

5. The photoresist composition of claim 1, wherein the weight average molecular weight of the novolac resin is 2000-15000, preferably 2000-8000, more preferably 3000-5000.

6. The photoresist composition of claim 1, wherein the plasticizer is selected from at least one of an epoxy compound, an ester compound, an ether compound, a polyol compound, and a polymer thereof.

7. The photoresist composition of claim 1, wherein the plasticizer is selected from at least one of 4,4- (1-isopropylidene) bis (2, 6-bismethylphenol), 2',4,4' -tetrahydroxybenzophenone, 2,3,4,4 '-tetrahydroxybenzophenone, 2',4 '-dihydroxypropiophenone, 2,4' -dihydroxydiphenylmethane, dibutyl phthalate, phthalate esters, diethyl phthalate, di (2-ethylhexyl) phthalate esters, methyl vinyl ethers, and polymethyl vinyl ethers.

8. The photoresist composition of claim 1, wherein the organic solvent is selected from at least one of propylene glycol methyl ether acetate, propylene glycol methyl ether, diheptanone, methyl isobutyl ketone, ethyl lactate, anisole, cyclopentanone, xylene, ethyl acetate, and butyl acetate.

9. Use of the photoresist composition of any one of claims 1 to 8 as a G-line photoresist or an I-line photoresist.

Technical Field

The application relates to the technical field of micro-electro-mechanical systems or organic light emitting diodes, in particular to a photoresist composition and application thereof.

Background

In recent years, the application of optical devices has increased dramatically, and very complicated multifunctional instruments, such as smart phones or cameras, are generally implanted. At the heart of this type of optics is a micromirror array, which is used for the collection or emission of light. Currently, the most common method used in industry to fabricate micromirror arrays is thermal reflow of photoresist. The photoresist functions as a pattern transfer, i.e., transferring a pattern from the reticle to a corresponding substrate. One of the most common methods is: a photoresist is coated on a substrate, exposed and developed to obtain a pattern, generally a pattern of regularly arranged lines, columns or cylinders, which is then heated and reflowed to flow into a semicircular shape.

Generally, the glass transition temperature (Tg) of the resin in the photoresist is 100-120 ℃, but the unexposed photosensitizer in the photoresist can be decomposed at high temperature to be used as a cross-linking agent to initiate resin cross-linking, the Tg of the cross-linked resin is 140-150 ℃, and in order to obtain a better micro-mirror appearance, the reflux temperature is at least 50 ℃ higher than the Tg, namely more than 200 ℃. However, due to the limitation of the production process with severe temperature requirement, too high temperature cannot be used, and therefore, it is urgently needed to develop a photoresist with lower reflow temperature.

Disclosure of Invention

In view of the above problems of the prior art, it is an object of the present application to provide a photoresist composition and its use to achieve a reduction in reflow temperature.

A first aspect of the present application provides a photoresist composition comprising the following components in parts by weight: 10-50 parts of linear phenolic resin, 1-10 parts of photosensitizer, 0.1-5 parts of plasticizer, 0.1-5 parts of additive and 40-100 parts of organic solvent;

the additive comprises at least one of the compounds of formula (I):

wherein R is₁-R₅Each independently selected from hydrogen, halogen atom, hydroxyl group, ether group, ester group, phenyl group, C₁-C₁₀Alkyl of (C)₃-C₁₀A cycloalkyl group of (a), a sulfonic acid group unsubstituted or substituted with Ra, an amino group unsubstituted or substituted with Ra;

each Ra is independently selected from C₆-C₁₀Cycloalkyl or phenyl.

A second aspect of the present application provides a use of the photoresist composition of the present application as a G-line photoresist or an I-line photoresist.

The photoresist composition provided by the application comprises the following components in parts by weight: 10-50 parts of phenolic resin, 1-10 parts of photosensitizer, 0.1-5 parts of plasticizer, 0.1-5 parts of additive and 40-100 parts of organic solvent, wherein the additive comprises at least one of compounds shown in a structural formula (I). The addition of the additive makes the photoresist composition of the present application flow more easily at low temperature to obtain better micromirror morphology. The additive can not be bleached and absorbed on G lines and I lines, and after illumination development, the appearance of the micro-mirror array is more trapezoidal, so that the micro-mirror array is more convenient to flow and form. The photoresist is used as a G-line photoresist or an I-line photoresist, can be rapidly reflowed at a lower temperature to form a micromirror array with good appearance, and can be used in a production process with strict requirement on temperature. And smaller size, or higher aspect ratio patterns can also reflow to form a good looking micromirror array.

Of course, not all advantages described above need to be achieved at the same time in the practice of any one product or method of the present application.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only one embodiment of the present application, and other embodiments can be obtained by those skilled in the art according to the drawings.

FIGS. 1a, 1b and 1c are schematic diagrams of a method for fabricating a micromirror array according to an embodiment of the present application;

FIGS. 2a and 2b are the photoresist features before and after reflow in example 1 of the present application;

FIGS. 3a and 3b are the photoresist features before and after reflow in example 2 of the present application;

FIGS. 4a and 4b are the photoresist features before and after reflow in example 3 of the present application;

FIGS. 5a and 5b are the photoresist features before and after reflow in example 4 of the present application;

FIGS. 6a and 6b are the photoresist features before and after reflow in example 5 of the present application;

FIGS. 7a and 7b are the photoresist features before and after reflow in example 6 of the present application;

FIGS. 8a and 8b are the photoresist features before and after reflow in example 7 of the present application;

FIGS. 9a and 9b are the photoresist features before and after reflow in example 8 of the present application;

FIGS. 10a and 10b are the photoresist features before and after reflow in example 9 of the present application;

FIGS. 11a and 11b show the photoresist features before and after reflow in comparative example 1 of the present application.

Reference numerals: 10. the manufacturing method comprises the following steps of a substrate, 20 photoresist patterns with a cylindrical structure, 30 micro mirror arrays, 31 photoresist patterns with a hemispherical structure, 40 photoresist layers and 50 mask plates.

Detailed Description

The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in this application are within the scope of protection of this application.

A first aspect of the present application provides a photoresist composition comprising the following components in parts by weight: 10-50 parts of linear phenolic resin, 1-10 parts of photosensitizer, 0.1-5 parts of plasticizer, 0.1-5 parts of additive and 40-100 parts of organic solvent; preferably, 15-40 parts of linear phenolic resin, 2-8 parts of photosensitizer, 0.1-2 parts of plasticizer, 0.1-2 parts of additive and 50-80 parts of organic solvent; the additive comprises at least one of the compounds represented by the structural formula (I):

wherein R is₁-R₅Each independently selected from hydrogen, halogen atom, hydroxyl group, ether group, ester group, phenyl group, C₁-C₁₀Alkyl of (C)₃-C₁₀Cycloalkyl of (a), sulfonic acid group unsubstituted or substituted by Ra, unsubstituted or substituted by RaAn amino group; each of the foregoing Ra is independently selected from C₆-C₁₀Cycloalkyl or phenyl.

Preferably, the additive may comprise at least one of the following compounds D1-D4:

it should be understood by those skilled in the art that, in the present application, the "parts" are not limited to specific mass units, and those skilled in the art can select the parts according to actual situations, and only need to add the parts according to the proportion. For example: g. kg or t, etc.

The additive of the application can flow more easily at low temperature, so that the photoresist composition can be rapidly reflowed at low temperature of less than or equal to 110 ℃ to form a micromirror array with good appearance. In addition, the additive can not be bleached and absorbed on G lines and I lines, and after illumination development, the appearance of the micro-mirror array is more trapezoidal, so that the micro-mirror array is more convenient to flow and form.

The photoresist composition has a low reflow temperature, can avoid the crosslinking temperature of resin, can rapidly reflow at a low temperature of less than or equal to 110 ℃ to form a hemispherical micro-mirror array with good appearance, and can be used in a production process with strict requirements on temperature. And the method still meets the reflow process aiming at the graphs with smaller size or larger aspect ratio, does not have the phenomenon of bulge at the top, and can reflow to form the micro-mirror array with good appearance.

In one embodiment of the present application, the components of the photoresist composition may further include a leveling agent and the like. In the present application, the kind of leveling agent is not particularly limited as long as the object of the present application can be achieved. For example, the leveling agent may be selected from at least one of an ionic surfactant and a non-ionic surfactant. Nonionic surfactants are preferred. Specifically, FC-4430 surfactant (manufacturer: 3M, USA), FC-4432 surfactant (manufacturer: 3M, USA), fluoro-diol, POLYFOX PF-636 (manufacturer: Ono chemical (Shanghai) Co., Ltd.), POLYFOX PF-6320 (manufacturer: Ono chemical (Shanghai) Co., Ltd.), POLYFOX PF-656 (manufacturer: Ono chemical (Shanghai) Co., Ltd.), POLYFOX PF-6520 (manufacturer: Ono chemical (Shanghai) Co., Ltd.), and the like may be included. The amount of the leveling agent used herein is not particularly limited as long as the object of the present application can be achieved. The use of the leveling agent can reduce the surface tension between the phenolic novolac resin, the photosensitizer, the plasticizer and the organic solvent in the photoresist composition, so that the phenolic novolac resin, the photosensitizer and the plasticizer are uniformly dispersed in the organic solvent. Further, the photoresist layer coated by the photoresist composition has uniform distribution of linear resin, photosensitizer and plasticizer, and can prevent the photoresist layer from generating spots or linear stains.

In one embodiment of the present application, the novolac resin includes at least one of polycondensates obtained by condensation polymerization of cresol-based compounds and aldehydes. In the present application, the p-cresol-based compound is not particularly limited as long as the object of the present application can be achieved. For example, the cresols may include at least one of m-cresol, p-cresol, o-cresol, xylenol, and trimethylphenol. In the present application, the aldehyde compound is not particularly limited as long as the object of the present application can be achieved. For example, the aldehyde compound may include at least one of formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and salicylaldehyde.

Preferably, the phenol novolac resin comprises a polycondensate obtained by condensation polymerization of m-cresol and p-cresol with formaldehyde, wherein the molar ratio of m-cresol to p-cresol is 1:1 to 1:4, preferably 1:1 to 1: 2.5.

The novolac resin of any of the foregoing embodiments can improve the chemical resistance and adhesion of the photoresist composition. The phenol novolac resin of the preferred embodiment can further significantly improve the chemical resistance and adhesion of the photoresist composition.

In one embodiment of the present application, the weight average molecular weight of the phenolic novolac resin is 2000-15000, preferably 2000-8000, more preferably 3000-5000. When the weight average molecular weight of the phenol novolac resin is too small (for example, less than 2000), the heat resistance of the phenol novolac resin is reduced, and the phenomenon of softening and flowing of the photoresist is easily caused; when the weight average molecular weight of the novolac resin is too large (e.g., greater than 15000), the sensitivity of the novolac resin is low, which results in an increase in the energy required to expose the photoresist layer. By controlling the weight average molecular weight of the novolac resin within the above range, the photoresist has high heat resistance temperature and good photosensitivity.

In one embodiment of the present application, the photosensitizer includes a compound formed by reacting diazonaphthoquinone with a polycyclic compound having a plurality of phenolic hydroxyl groups; wherein the mol ratio of the diazonaphthoquinone to the polycyclic compound with a plurality of phenolic hydroxyl groups is 1:1-1:4, preferably 1:2-1: 3.

In the present application, the kind of the diazonaphthoquinone is not particularly limited as long as the object of the present application can be achieved. For example, the diazonaphthoquinone may be selected from 2-diazo-1-naphthoquinone-4-sulfonyl chloride or 2-diazo-1-naphthoquinone-5-sulfonyl chloride. In the present application, the kind of polycyclic compound having a plurality of phenolic hydroxyl groups is not particularly limited as long as the object of the present application can be achieved. For example, the polycyclic compound having a plurality of phenolic hydroxyl groups may be selected from any one of 2,3, 4-trihydroxybenzophenone, 2',4,4' -tetrahydroxybenzophenone, 2',3, 4-tetrahydroxybenzophenone, 2,3,4,4' -Tetrahydroxybenzophenone (THBP), 1,1, 1-tris (4-hydroxyphenyl) ethane or 1,1, 1-tris (4-hydroxyphenyl) methane, preferably 2,2',4,4' -tetrahydroxybenzophenone or 2,2',3, 4-tetrahydroxybenzophenone.

For example, the photosensitizer may include at least one of the following compounds B1 and B2. Wherein the compound B1 is prepared by the reaction of 2,3,4,4 '-tetrahydroxybenzophenone and 2-diazo-1-naphthoquinone-5-sulfonyl chloride (DNQ) according to the molar ratio of 1:2, and the compound B2 is prepared by the reaction of 2,3,4,4' -tetrahydroxybenzophenone and 2-diazo-1-naphthoquinone-5-sulfonyl chloride according to the molar ratio of 1: 3.

The photosensitizer contains diazonaphthoquinone and polycyclic compounds with a plurality of phenolic hydroxyl groups, so that the photoresist composition has photosensitive characteristics, can generate chemical reaction after exposure, and can be dissolved in a developing solution.

In one embodiment herein, the plasticizer is selected from at least one of an epoxy compound, an ester compound, an ether compound, a polyol compound, and a polymer thereof. Preferably, the plasticizer is at least one selected from the group consisting of 4,4- (1-isopropylidene) bis (2, 6-bismethylphenol) (C1), 2',4,4' -tetrahydroxybenzophenone, 2,3,4,4 '-tetrahydroxybenzophenone, 2',4 '-dihydroxypropiophenone, 2,4' -dihydroxydiphenylmethane, dibutyl phthalate, phthalate esters, diethyl phthalate, di (2-ethylhexyl) phthalate esters, methyl vinyl ethers and polymethyl vinyl ethers. The use of the above plasticizer increases the photospeed, so that the energy required for exposing the photoresist composition is reduced, the photoresist composition flows at a lower temperature, and the photolithography efficiency can be improved.

In one embodiment of the present application, the organic solvent is selected from at least one of Propylene Glycol Methyl Ether Acetate (PGMEA), Propylene Glycol Methyl Ether (PGME), diheptanone, methyl isobutyl ketone, ethyl lactate, anisole, cyclopentanone, xylene, ethyl acetate, and butyl acetate. Preferably at least one selected from PGMEA, ethyl lactate and diheptanone. The organic solvent has good solubility and coating performance, and the phenolic novolac resin, the photosensitizer, the plasticizer and the additive in the photoresist composition can be more uniformly dissolved in the organic solvent by selecting the organic solvent, so that the phenolic novolac resin, the photosensitizer, the plasticizer and the additive in the photoresist layer formed by the photoresist composition are more uniformly distributed.

In the present application, there is no particular limitation on the method for preparing the photoresist composition, as long as the object of the present application can be achieved. For example, a method of preparing a photoresist composition of the present application may comprise the steps of: dissolving the linear phenolic resin, the photosensitizer, the plasticizer and the additive in an organic solvent, and uniformly mixing to obtain a photoresist composition; wherein, the weight portion of the phenolic novolac resin is 10 to 50 portions, the photosensitizer is 1 to 10 portions, the plasticizer is 0.1 to 5 portions, the additive is 0.1 to 5 portions, and the organic solvent is 40 to 100 portions.

It should be noted that, since Ultraviolet (UV) rays are included in natural light, in order to prevent chemical reaction caused by UV during the preparation of the photoresist composition and influence the chemical stability of the photoresist composition, in one embodiment of the present application, the photoresist composition is prepared in an environment without UV. For example, the phenolic novolac resin, the sensitizer, the plasticizer and the additive are dissolved in the organic solvent under the yellow environment and are mixed uniformly to obtain the photoresist composition.

In the present application, the order of mixing the above-mentioned phenol novolac resin, sensitizer, plasticizer, additive and organic solvent, the mixing time and the mixing temperature are not particularly limited as long as the object of the present application can be achieved.

A second aspect of the present application provides a use of the photoresist composition of the present application as a G-line photoresist or an I-line photoresist. The photoresist composition is used as a G-line photoresist, and the wavelength of an exposure light source is 436 nm. The photoresist composition of the present application was used as an I-line photoresist with an exposure light source of 365 nm.

The photoresist is an etching-resistant thin film material whose solubility changes by irradiation or radiation of ultraviolet light, electron beam, ion beam, X-ray, or the like. Are commonly used as materials for corrosion-resistant coatings during photolithographic processes. Photoresists can be classified into positive photoresists and negative photoresists according to their chemical reaction mechanism and development principle. The exposed area of the positive photoresist can generate photolysis reaction, so that the photoresist is degraded into substances which can be dissolved in a developing solution, and the non-exposed area of the photoresist can form a photoresist pattern which is the same as or basically the same as that of the mask plate. The exposed area of the negative photoresist can generate a crosslinking reaction and can not be dissolved in a developing solution, and the non-exposed area can be dissolved in the developing solution, so that the non-exposed area of the photoresist can form a photoresist pattern which is complementary or basically complementary with the pattern of the mask plate.

The photoresist composition provided by the present application is used as a G-line photoresist or an I-line photoresist, and is a positive photoresist, i.e., the photoresist composition is not dissolved in a developing solution before exposure, and after exposure, the chemical properties of the irradiated portion are changed, and the changed portion can be dissolved in the developing solution and removed.

The photoresist of the present application can be used as a base material for fabricating a micromirror array. In the present application, there is no particular limitation on the method of manufacturing the micromirror array as long as the object of the present application can be achieved. For example, the present application can employ a method of fabricating a micromirror array comprising the steps of:

(1) forming a photoresist layer having a thickness of 1-2 μm on a surface of a substrate, the photoresist layer comprising the photoresist composition of the present application;

(2) exposing the photoresist layer by using a mask plate;

(3) developing the exposed photoresist layer to obtain a photoresist pattern;

(4) and baking the photoresist pattern to reflow the photoresist pattern, thereby obtaining the micro-mirror array.

In this application, the term "micromirror array" refers to an array consisting of lenses with clear apertures and relief depths on the order of micrometers.

The method of forming a photoresist layer, exposing, and developing is not particularly limited as long as the object of the present invention can be achieved. For example, the photoresist layer may be formed by spray coating, flow coating, immersion coating, roll coating, spin coating, or the like. The exposure method may include contact exposure, proximity exposure, projection exposure, or the like. The developing method can comprise whole box silicon wafer immersion developing, continuous spray developing or puddle developing, etc. The developer to be used for development is not particularly limited as long as the object of the present invention can be achieved. For example, the developer solution may include tetramethylammonium hydroxide and the like.

It should be noted that, when the photoresist composition of the present application is used to manufacture a micromirror array, in step (4), the reflow temperature of the photoresist pattern is less than or equal to 110 ℃, and therefore, the photoresist pattern can be rapidly reflowed at low temperature to form a good-profile semicircular micromirror array. The time of the reflux is not particularly limited as long as the object of the present application can be achieved.

In one embodiment of the present application, as shown in fig. 1a, a photoresist layer 40 having a thickness of 1-2 μm is coated on a substrate 10, uv-exposure is performed under a circular array of mask plates 50, and the exposed photoresist layer 40 is developed; as shown in fig. 1b, the photoresist pattern 20 with a cylindrical structure is obtained after development; as shown in fig. 1c, the cylindrical photoresist pattern 20 is heated to a molten state and reflows, and the surface tension thereof transforms the cylindrical photoresist pattern 20 into a hemispherical photoresist pattern 31, thereby obtaining a micromirror array 30.

The photoresist composition is used as a G-line photoresist or an I-line photoresist to manufacture a micromirror array, a hemispherical micromirror array with good appearance can be obtained at a low reflow temperature of less than or equal to 110 ℃, a pattern with small size or large aspect ratio can be reflowed to form the micromirror array with good appearance, and the resolution is high.

The embodiments of the present application will be described in more detail below with reference to examples and comparative examples. The experiments and evaluations of the respective examples and comparative examples were carried out in accordance with the following methods. Unless otherwise specified, "part" and "%" are based on mass.

The test method and the test equipment comprise:

the resolution testing method comprises the following steps:

(1) spin coating on a 6-inch silicon wafer by using a glue spreader (manufacturer: Tokyo electronics Co., Ltd., model: Mark V), adjusting the spin coating speed according to the thickness of the photoresist layer, baking for the first time at 90 ℃ for 60s after the spin coating is finished, and then cooling to measure the film thickness to form a photoresist layer with the thickness of 2 microns;

(2) then, the substrate is placed into an I-line exposure machine (manufacturer: Nikon I9, model: Nikon I9, and Numerical Aperture (NA) ═ 0.57) for exposure, a mask plate is provided with a line width of 2-0.25 μm, the ratio of the line width to the grating spacing is 1:1-1:5, exposure time is set to be 20-2000ms for exposure, and the exposure amount is 10-1000 mJ;

(3) then developing with 2.38 wt% tetramethyl ammonium hydroxide aqueous solution at 23 deg.C for 60 s;

(4) finally, the resolution was evaluated using a photoresist picture obtained by a scanning electron microscope (CD-SEM) (manufacturer: Hitachi, model 8840) for characteristic dimension measurement.

And (3) testing the reflow performance:

and (3) placing the wafer observed by the CD-SEM on a hot plate again for baking to enable the wafer to reflow, wherein the reflow temperature is 105-110 ℃, the reflow time is 90-180s, and observing the shape of the reflowed photoresist by an X-SEM slice (manufacturer: Hitachi, model 4800).

And (3) testing the photosensitive speed:

the exposure dose in step (2) of the resolution test method, i.e., exposure energy: when the measured line width on the photoresist picture is consistent with the actual value on the mask, the measured line width is the optimal exposure of the line width, and is also the photosensitive speed value of the formula, namely the result of the photosensitive speed.

Example 1

< preparation of Photoresist composition >

20 parts of phenolic novolac A1, 3 parts of photosensitizer B2, 1 part of plasticizer C1, 0.3 part of additive D1 and 0.01 part of leveling agent fluoro-diol were dissolved in 57 parts of PGMEA to prepare a solution with a solid content of 30%, and the solution was filtered through a filter membrane with a pore size of 0.2 μm to obtain a photoresist composition. The linear phenolic resin A1 is prepared by condensation polymerization of m-cresol, p-cresol and formaldehyde, wherein the molar ratio of m-cresol to p-cresol is 1:1.5, and the weight average molecular weight of A1 is 3750.

< preparation of micromirror array >

Forming a photoresist layer with the thickness of 2 mu m on the surface of the substrate, wherein the photoresist layer adopts the photoresist composition;

exposing the photoresist layer by using a mask plate;

developing the exposed photoresist layer to obtain a photoresist pattern with a height of 0.7 μm, as shown in FIG. 2 a;

the photoresist pattern was baked on a hot plate and reflowed at a reflow temperature of 110 c for a reflow time of 60s to obtain a micromirror array with a height of 0.7 μm as shown in fig. 2 b.

Example 2

The procedure of example 1 was repeated, except that D2 was used as an additive in < preparation of resist composition >.

Example 3

The procedure of example 1 was repeated, except that in < preparation of resist composition >, 1 part by mass of the sensitizer B2 was used, and D3 was used as an additive.

Example 4

The procedure of example 1 was repeated, except that D4 was used as an additive in < preparation of resist composition >.

Example 5

The procedure of example 1 was repeated, except that A2 was used as the novolak resin in < preparation of the resist composition >. The linear phenolic resin A2 is prepared by condensation polymerization of m-cresol, p-cresol and formaldehyde, wherein the molar ratio of m-cresol to p-cresol is 1:1, and the weight average molecular weight of A2 is 6000.

Example 6

The procedure of example 1 was repeated, except that A3 was used as the novolak resin in < preparation of the resist composition >. The linear phenolic resin A3 is prepared by condensation polymerization of m-cresol, p-cresol and formaldehyde, wherein the molar ratio of m-cresol to p-cresol is 1:1, and the weight average molecular weight of A3 is 7000.

Example 7

The same as example 1 except that in < preparation of resist composition >, B1 was used as the sensitizer.

Example 8

The procedure of example 1 was repeated, except that the photosensitizer used in < preparation of photoresist composition > was a mixture of B1: B2 ═ 1:1.

Example 9

The same as example 1 was repeated except that in < preparation of micromirror array >, the reflow temperature was 105 ℃.

Comparative example 1

The same as example 1 except that no additive was added in < preparation of photoresist composition >.

The preparation parameters and test results of examples 1 to 8 and comparative example 1 are shown in table 1:

TABLE 1

Note: the "/" in table 1 indicates no corresponding preparation parameters.

As can be seen from Table 1 and FIGS. 2 to 11, the photoresist compositions of examples 1 to 9 generally have significantly better resolution and sensitivity than the photoresist composition of comparative example 1. Moreover, the micromirror array prepared by using the photoresist composition of examples 1-9 is a semicircular or near-semicircular micromirror array with good morphology; in contrast, the micromirror array prepared by using the photoresist composition of comparative example 1 has a significant protrusion on the top. Thus, the photoresist composition provided by the application has low reflow temperature, high resolution and high photospeed, and can be rapidly reflowed at the low reflow temperature of less than or equal to 110 ℃ to form a good hemispherical micro-mirror array by using the photoresist composition provided by the application.

The above description is only for the preferred embodiment of the present application and is not intended to limit the scope of the present application. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application are included in the protection scope of the present application.