阅读说明：本技术 光刻方法 (Photoetching method ) 是由 韩建伟 吴长明 姚振海 陈骆 王绪根 朱联合 于 2021-08-05 设计创作，主要内容包括：本申请涉及半导体集成电路制造技术领域,具体涉及一种光刻方法。光刻方法包括以下步骤：提供待涂胶的基片；在基片的表面喷涂增黏剂,形成增黏层；在增黏层上涂覆疏水光刻胶,形成具有特定厚度的疏水光刻胶层；对疏水光刻胶层进行曝光操作,使得疏水光刻胶层上形成感光区和非感光区；通过显影液,对曝光操作后的疏水光刻胶层进行显影操作,使得感光区中疏水光刻胶的分子量减小,分子量减小的疏水光刻胶至少部分溶解在显影液中；向显影操作后的疏水光刻胶层上,喷淋表面活性溶液,使得感光区中分子量减小的残留疏水光刻胶与表面活性溶液的疏水基结合,在亲水基的亲水作用下使得分子量减小的残留疏水光刻胶,剥离感光区位置处的基片表面。(The present application relates to the field of semiconductor integrated circuit manufacturing technology, and more particularly, to a photolithography method. The photoetching method comprises the following steps: providing a substrate to be glued; spraying a tackifier on the surface of the substrate to form a tackifying layer; coating hydrophobic photoresist on the adhesion promoting layer to form a hydrophobic photoresist layer with a specific thickness; exposing the hydrophobic photoresist layer to form a photosensitive area and a non-photosensitive area on the hydrophobic photoresist layer; carrying out development operation on the hydrophobic photoresist layer after the exposure operation through a developing solution, so that the molecular weight of the hydrophobic photoresist in the photosensitive area is reduced, and the hydrophobic photoresist with the reduced molecular weight is at least partially dissolved in the developing solution; and spraying a surface active solution on the hydrophobic photoresist layer after the development operation to combine the residual hydrophobic photoresist with the reduced molecular weight in the photosensitive area with the hydrophobic group of the surface active solution, and stripping the surface of the substrate at the position of the photosensitive area by the residual hydrophobic photoresist with the reduced molecular weight under the hydrophilic action of the hydrophilic group.)

1. A lithographic method, comprising:

providing a substrate to be glued;

spraying a tackifier on the surface of the substrate to form a tackifying layer;

coating hydrophobic photoresist on the adhesion promoting layer to form a hydrophobic photoresist layer with a specific thickness;

according to a specific photoetching mask pattern, carrying out exposure operation on the hydrophobic photoresist layer to form a photosensitive area and a non-photosensitive area on the hydrophobic photoresist layer;

carrying out development operation on the hydrophobic photoresist layer after the exposure operation through a developing solution, so that the molecular weight of the hydrophobic photoresist in the photosensitive area is reduced, and the hydrophobic photoresist with the reduced molecular weight is at least partially dissolved in the developing solution;

after to the development operation on the hydrophobic photoresist layer, spray the surface active solution including hydrophilic group and hydrophobic group, make in the sensitization district, the remaining hydrophobic photoresist that molecular weight reduces with the hydrophobic group of surface active solution combines make the remaining hydrophobic photoresist that molecular weight reduces under the hydrophilic effect of hydrophilic group, peel off the substrate surface of sensitization district position department.

2. The photolithography method according to claim 1, wherein the step of spraying the adhesion promoter on the surface of the substrate to be coated to form the adhesion promoter layer comprises:

heating the substrate to any temperature between 100 ℃ and 180 ℃;

spraying the tackifier in a gaseous form in a dose of 0.03ml to 0.05ml so as to flow to the periphery of the substrate for a time of 20s to 50 s;

and maintaining the ambient environment of the substrate at any temperature between 100 ℃ and 180 ℃ for 20s to 50s, so that the tackifier gas and the surface of the substrate fully react to form the hydrophobic tackifying layer.

3. The method of claim 1, wherein the step of applying a hydrophobic photoresist on the adhesion promotion layer to form a hydrophobic photoresist layer comprises:

rotating the substrate with the adhesion promoting layer at a rotating speed of 800RPM to 2000 RPM;

spraying hydrophobic photoresist with the dosage of 0.5ml to 6ml onto the upper surface of the adhesion promotion layer;

and under the action of centrifugal force, the hydrophobic photoresist is made to be spread on the upper surface of the adhesion promotion layer, and a hydrophobic photoresist layer with a specific thickness is formed after baking.

4. The method of claim 1, wherein said step of spraying a surface active solution comprising hydrophilic groups and hydrophobic groups onto said hydrophobic photoresist layer after said developing operation such that residual hydrophobic photoresist having a reduced molecular weight in said photosensitive regions is bound to the hydrophobic groups of said surface active solution and said residual hydrophobic photoresist is released from the surface of the substrate at the location of said photosensitive regions by the hydrophilic action of said hydrophilic groups comprises:

determining an actual thickness of the hydrophobic photoresist layer;

determining the required spraying dosage and the required spraying time of the surface active solution corresponding to the actual thickness of the hydrophobic photoresist layer based on the corresponding relation between the pre-stored thickness of the hydrophobic photoresist and the spraying dosage and the spraying time of the surface active solution;

according to the demand sprays dose and demand spray time, to after the development operation on the hydrophobic photoresist layer, spray the surface active solution including hydrophilic group and hydrophobe, make in the sensitization district, the remaining hydrophobic photoresist that molecular weight reduces with the hydrophobe of surface active solution combines make under the hydrophilic action of hydrophilic group the remaining hydrophobic photoresist breaks away from the substrate surface of sensitization district position department.

5. The photolithography method according to claim 1, wherein the step of spraying a surface active solution comprising hydrophilic groups and hydrophobic groups onto the hydrophobic photoresist layer after the developing operation, so that the residual hydrophobic photoresist with reduced molecular weight in the photosensitive region is combined with the hydrophobic groups of the surface active solution, and the step of releasing the residual hydrophobic photoresist from the substrate surface at the position of the photosensitive region under the hydrophilic action of the hydrophilic groups is further performed after:

and spraying deionized water on the surface of the substrate, so that the stripped residual hydrophobic photoresist is taken away by the fluidity of the deionized water.

6. The lithographic method of claim 1, wherein said surface active solution comprises a surface active solute and an aqueous solvent, said surface active solute being dissolved in said aqueous solvent;

the molecular structure of the surface active solute comprises: hydrophilic and hydrophobic groups located at opposite ends of the molecular structure, respectively.

7. The lithographic method of claim 1, wherein said adhesion promotion layer comprises a hydrophobic group, said hydrophobic photoresist layer being hydrophobic;

the adhesion promoting layer is used as a coupling agent of the hydrophobic photoresist layer and the surface of the substrate.

8. A lithographic method according to claim 1, wherein said photosensitive region has a solubility in a developer that is substantially greater than a solubility of said non-photosensitive region in the developer.

Technical Field

The present application relates to the field of semiconductor integrated circuit manufacturing technology, and more particularly, to a photolithography method.

Background

In the production of semiconductor integrated circuits, the photolithography process, which is a key step in the process of manufacturing integrated circuit patterns, has a significant impact on the quality, yield and cost of the product.

Generally, the photolithography process transfers a pattern on a mask plate to a photoresist coated on a wafer surface through three steps of gumming, exposing and developing.

However, the number of products or the number of layers of photoresist in the chip processing process is large, and the types and properties of the photoresist required by different products are different. The adhesion of different photoresists on the wafer is different, that is, some kinds of photoresists form patterns on the wafer and have a collapse problem, or some kinds of photoresists have a photoresist residue problem after exposure and development, which has a serious adverse effect on the manufacture of wafer integrated circuit patterns.

In the related art, an adhesion promoter such as hexamethyldisilazane is usually used, i.e. a layer of adhesion promoter is coated on the wafer surface before the photoresist is coated, so as to improve the adhesion between the photoresist and the wafer surface and prevent the collapse of the photoresist pattern. However, after the adhesion is increased, the problem of photoresist residue increases in the development open area.

Disclosure of Invention

The application provides a photoetching method which can solve the problems of collapse of photoetching patterns and residual hydrophobic photoresist in the related technology.

In order to solve the technical problems described in the background art, the present application provides a photolithography method including the steps of:

providing a substrate to be glued;

spraying a tackifier on the surface of the substrate to form a tackifying layer;

coating hydrophobic photoresist on the adhesion promoting layer to form a hydrophobic photoresist layer with a specific thickness;

according to a specific photoetching mask pattern, carrying out exposure operation on the hydrophobic photoresist layer to form a photosensitive area and a non-photosensitive area on the hydrophobic photoresist layer;

carrying out development operation on the hydrophobic photoresist layer after the exposure operation through a developing solution, so that the molecular weight of the hydrophobic photoresist in the photosensitive area is reduced, and the hydrophobic photoresist with the reduced molecular weight is at least partially dissolved in the developing solution;

after to the development operation on the hydrophobic photoresist layer, spray the surface active solution including hydrophilic group and hydrophobic group, make in the sensitization district, the remaining hydrophobic photoresist that molecular weight reduces with the hydrophobic group of surface active solution combines make the remaining hydrophobic photoresist that molecular weight reduces under the hydrophilic effect of hydrophilic group, peel off the substrate surface of sensitization district position department.

Optionally, the step of spraying a tackifier on the surface of the substrate to be glued to form a tackifying layer includes:

heating the substrate to any temperature between 100 ℃ and 180 ℃;

spraying the tackifier in a gaseous form in a dose of 0.03ml to 0.05ml so as to flow to the periphery of the substrate for a time of 20s to 50 s;

and maintaining the ambient environment of the substrate at any temperature between 100 ℃ and 180 ℃ for 20s to 50s, so that the tackifier gas and the surface of the substrate fully react to form the hydrophobic tackifying layer.

Optionally, the step of coating a hydrophobic photoresist on the adhesion promotion layer to form a hydrophobic photoresist layer includes:

rotating the substrate with the adhesion promoting layer at a rotating speed of 800RPM to 2000 RPM;

spraying hydrophobic photoresist with the dosage of 0.5ml to 6ml onto the upper surface of the adhesion promotion layer;

and under the action of centrifugal force, the hydrophobic photoresist is made to be spread on the upper surface of the adhesion promotion layer, and a hydrophobic photoresist layer with a specific thickness is formed after baking.

Optionally, the step of spraying a surface active solution including a hydrophilic group and a hydrophobic group onto the hydrophobic photoresist layer after the developing operation, so that the residual hydrophobic photoresist with reduced molecular weight in the photosensitive area is bonded with the hydrophobic group of the surface active solution, and the residual hydrophobic photoresist is separated from the surface of the substrate at the position of the photosensitive area under the hydrophilic action of the hydrophilic group includes:

determining an actual thickness of the hydrophobic photoresist layer;

determining the required spraying dosage and the required spraying time of the surface active solution corresponding to the actual thickness of the hydrophobic photoresist layer based on the corresponding relation between the pre-stored thickness of the hydrophobic photoresist and the spraying dosage and the spraying time of the surface active solution;

according to the demand sprays dose and demand spray time, to after the development operation on the hydrophobic photoresist layer, spray the surface active solution including hydrophilic group and hydrophobe, make in the sensitization district, the remaining hydrophobic photoresist that molecular weight reduces with the hydrophobe of surface active solution combines make under the hydrophilic action of hydrophilic group the remaining hydrophobic photoresist breaks away from the substrate surface of sensitization district position department.

Optionally, after the step of spraying a surface active solution including a hydrophilic group and a hydrophobic group onto the hydrophobic photoresist layer after the developing operation is performed, so that the residual hydrophobic photoresist with reduced molecular weight in the photosensitive area is combined with the hydrophobic group of the surface active solution, and the residual hydrophobic photoresist is separated from the surface of the substrate at the position of the photosensitive area under the hydrophilic action of the hydrophilic group, the method further comprises:

and spraying deionized water on the surface of the substrate, so that the stripped residual hydrophobic photoresist is taken away by the fluidity of the deionized water.

Optionally, the surface active solution comprises a surface active solute and an aqueous solvent, the surface active solute being dissolved in the aqueous solvent;

the molecular structure of the surface active solute comprises: hydrophilic and hydrophobic groups located at opposite ends of the molecular structure, respectively.

Optionally, the adhesion promotion layer comprises a hydrophobic group, and the hydrophobic photoresist layer has hydrophobicity;

the adhesion promoting layer is used as a coupling agent of the hydrophobic photoresist layer and the surface of the substrate.

Optionally, the photosensitive region has a solubility in a developer that is substantially greater than a solubility of the non-photosensitive region in the developer.

The technical scheme at least comprises the following advantages: this application is through the adhesion promoter, treats gummed substrate surface and carries out the preliminary treatment before the rubber coating, reduces the moisture on this substrate surface on the one hand, and on the other hand adhesion promoter and the surperficial hydroxyl reaction of this substrate eliminate the hydrogen bonding on substrate surface for the substrate surface becomes hydrophobicity by hydrophilicity, and the hydrophobic base on adhesion promoter layer can combine with hydrophobic photoresist, improves the adhesiveness between hydrophobic photoresist and the substrate.

The molecular weight of the photoresist in the photosensitive area after development is utilized to be remarkably reduced, and the surface active solution comprising hydrophilic groups and hydrophobic groups is sprayed on the hydrophobic photoresist layer after the development operation, so that the hydrophobic photoresist remained in the photosensitive area after the molecular weight is reduced is combined with the hydrophobic groups of the surface active solution, the hydrophobic photoresist remained under the hydrophilic action of the hydrophilic groups is separated from the surface of the substrate at the position of the photosensitive area, and the problem of photoresist residue caused by the increase of the adhesiveness between the photoresist and the substrate in the photosensitive area is avoided.

Drawings

In order to more clearly illustrate the detailed description of the present application or the technical solutions in the prior art, the drawings needed to be used in the detailed description of the present application or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow chart of a photolithography method provided by an embodiment of the present application;

FIG. 2 shows a schematic diagram of a photoresist pattern collapse topography.

Detailed Description

The technical solutions in the present application will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; the connection can be mechanical connection or electrical connection; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

In addition, the technical features mentioned in the different embodiments of the present application described below may be combined with each other as long as they do not conflict with each other.

Fig. 1 shows a flowchart of a photolithography method provided in an embodiment of the present application, and referring to fig. 1, the photolithography method includes steps S1 to S7 performed in sequence:

step S1: and providing a substrate to be glued.

Step S2: and spraying a tackifier on the surface of the substrate to be glued to form a tackifying layer.

In order to make the adhesion promoter react with the surface of the substrate sufficiently and improve the adhesion between the substrate and the hydrophobic photoresist, the step S2: spraying a tackifier on the surface of the substrate to be glued to form a tackifying layer, wherein the following steps S21 to S23 are sequentially performed, wherein:

step S21: the substrate is heated to any temperature between 100 ℃ and 180 ℃. So that the substrate is fully and uniformly heated to reduce the moisture on the surface of the substrate.

Step S22: the adhesion promoter is sprayed in gaseous form at high temperature in a dose of 0.03ml to 0.05ml so as to flow to the periphery of the substrate for a period of 20s to 50 s.

Step S23: and maintaining the environment around the substrate at any temperature between 100 ℃ and 180 ℃ for 20s to 50s, so that the tackifier gas and the surface of the substrate fully react to form the hydrophobic tackifying layer.

Alternatively, the adhesion promoter in this embodiment may be trimethylsilyl, and the adhesion promoter layer formed includes a hydrophobic group.

In the related art, since the hydrophobic photoresist has hydrophobicity, and the hydroxyl groups and residual water molecules on the surface of the substrate to be coated are hydrophilic, the adhesion between the hydrophobic photoresist and the substrate is poor, and the photoresist pattern collapse after coating and photoetching is easy to occur, the collapse morphology structure schematic diagram of the photoresist pattern shown in fig. 2 is formed, and it can be seen from fig. 2 that the photoresist 220 which is formed on the substrate 210 and can define the photoresist pattern collapses.

And the surface of the substrate to be coated with glue is pretreated by the adhesion promoter before coating with glue, so that the moisture on the surface of the substrate is reduced, and the adhesion promoter reacts with hydroxyl on the surface of the substrate to eliminate the hydrogen bond on the surface of the substrate, so that the surface of the substrate is changed from hydrophilicity to hydrophobicity, and the hydrophobic group of the adhesion promoter can be combined with the hydrophobic photoresist to improve the adhesiveness between the hydrophobic photoresist and the substrate.

Step S3: and coating a hydrophobic photoresist on the adhesion promoting layer to form a hydrophobic photoresist layer with a specific thickness.

In order to make the hydrophobic photoresist layer formed on the adhesion promotion layer more uniform, the step S3: coating a hydrophobic photoresist on the adhesion promotion layer to form a hydrophobic photoresist having a specific thickness may include sequentially performing steps S31 to S33, wherein:

step S31: so that the substrate with the adhesion promotion layer formed thereon is rotated at a rotation speed of 800RPM to 2000RPM after the step S2 is completed.

Step S32: and spraying hydrophobic photoresist with the dosage of 0.5ml to 6ml onto the upper surface of the adhesion promoting layer.

In the implementation, the process can be set according to the photolithography process and the kind of the photoresist.

Step S33: and under the action of centrifugal force, the hydrophobic photoresist is made to be spread on the upper surface of the adhesion promotion layer, and a hydrophobic photoresist layer with a specific thickness is formed after baking.

Step S4: and carrying out exposure operation on the hydrophobic photoresist layer according to a specific photoetching mask pattern, so that a photosensitive area and a non-photosensitive area are formed on the hydrophobic photoresist layer.

Wherein the pattern of the lithography mask is determined by the mask according to requirements.

Typically, hydrophobic photoresists include: a photosensitive compound, a matrix material, and a solvent. For positive-working hydrophobic photoresists, the substrate material is soluble in the developer in the absence of a dissolution inhibitor, which typically acts as a strong dissolution inhibitor, reducing the dissolution rate of the substrate material. Under the irradiation of specific light, the photosensitive compound and the light are subjected to chemical reaction to form a solubility enhancer, so that the solubility factor in the developing solution can be greatly improved, and the solubility of the matrix material in the developing solution is increased. And partially shading the hydrophobic photoresist layer of the substrate by using a mask, wherein the mask is provided with a pattern in advance. The area of the hydrophobic photoresist layer shielded by the mask is a non-photosensitive area, and the area of the hydrophobic photoresist layer exposed without being shielded by the mask is a photosensitive area.

Wherein the solubility of the photosensitive region in a subsequent developer is much greater than the solubility of the non-photosensitive region in the developer.

Step S5: and developing the hydrophobic photoresist layer after the exposure operation by using a developing solution, so that the molecular weight of the hydrophobic photoresist in the photosensitive area is reduced, and at least part of the hydrophobic photoresist with the reduced molecular weight is dissolved in the developing solution.

Since the solubility of the hydrophobic photoresist in the photosensitive region in the developing solution is improved after the step S4 is completed, after the hydrophobic photoresist layer after the exposure operation is developed by the developing solution, the hydrophobic photoresist in the photosensitive region can react with the developing solution, so that the molecular weight is reduced, and the hydrophobic photoresist can be at least partially dissolved in the developing solution. However, for the non-photosensitive area, the solubility of the hydrophobic photoresist layer in the developing solution is unchanged and still smaller, so that the developing solution cannot react with the hydrophobic photoresist layer at the position of the non-photosensitive area, and the molecular weight of the hydrophobic photoresist layer at the position of the non-photosensitive area cannot be reduced.

However, in the photosensitive region, the hydrophobic photoresist with reduced molecular weight is affected by the adhesiveness, and the phenomenon that the hydrophobic photoresist is not completely dissolved in the developing solution occurs, that is, the problem of hydrophobic photoresist residue occurs in the photosensitive region.

In order to solve the problem of the hydrophobic photoresist residue, after step S5, the following steps are performed:

step S6: after to the development operation on the hydrophobic photoresist layer, spray the surface active solution including hydrophilic group and hydrophobic group, make in the sensitization district, the remaining hydrophobic photoresist that molecular weight reduces with the hydrophobic group of surface active solution combines make under the hydrophilic effect of hydrophilic group the remaining hydrophobic photoresist breaks away from the substrate surface of sensitization district position department.

It is to be construed that the surface active solution includes a surface active solute dissolved in an aqueous solvent, and the molecular structure of the surface active solute includes a hydrophilic group and a hydrophobic group respectively located at opposite ends of the molecular structure. The surface active solution comprises a hydrophilic group and a hydrophobic group, wherein the hydrophobic group is combined with the hydrophobic photoresist, the hydrophilic group of the surface active solution has a hydrophilic effect, and the molecular weight of the hydrophobic photoresist at the position of a photosensitive area is obviously reduced after the development operation is completed, so that under the hydrophilic effect of the hydrophilic group, the surface active solution enables the residual hydrophobic photoresist with the reduced molecular weight to be separated from the surface of the substrate at the position of the photosensitive area, enter the water of the surface active solution and take away the stripped residual hydrophobic photoresist along with the fluidity of the surface active solution.

In this embodiment, the step S6 may include the following steps S61 to S63 performed in this order:

step S61: the actual thickness of the hydrophobic photoresist layer formed is determined.

Step S62: and determining the required spraying dose and the required spraying time of the surface active solution corresponding to the thickness A of the hydrophobic photoresist layer based on the corresponding relation between the pre-stored thickness of the hydrophobic photoresist layer and the spraying dose and the spraying time of the surface active solution.

Step S63: according to the demand sprays dose and demand spray time, to after the development operation on the hydrophobic photoresist layer, spray the surface active solution including hydrophilic group and hydrophobe, make in the sensitization district, the remaining hydrophobic photoresist that molecular weight reduces with the hydrophobe of surface active solution combines make under the hydrophilic action of hydrophilic group the remaining hydrophobic photoresist breaks away from the substrate surface of sensitization district position department.

In order to more completely clarify the stripped residual hydrophobic photoresist, this embodiment further proceeds after step S6 is completed:

step S7: and spraying deionized water on the surface of the substrate, so that the stripped residual hydrophobic photoresist is taken away by the fluidity of the deionized water.

In this embodiment, the substrate may be rotated while spraying deionized water onto the surface of the substrate to improve the fluidity of the deionized water.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of this invention are intended to be covered by the scope of the invention as expressed herein.