Method for reducing process defects of spin coating developing equipment

Abstract

The invention relates to the field of semiconductors, and particularly discloses a method for reducing process defects of uniform glue developing equipment. According to the process provided by the invention, an accurate developing liquid dropping mode is adopted, the moving distance of dropping liquid is shortened, the over-developing phenomenon of developing can be effectively avoided, the stability and repeatability of developing are improved, the exhaust air rate in a baking stabilizing chamber is increased, impurity accumulation in a hot plate cavity is effectively reduced, and the quality of the hot plate is improved. Volatilized by-products of the photosensitive glue in the heating process are removed in time, the uniformity of the heating effect of the photosensitive glue layer is prevented from being affected, the rotary glue spinning speed after standing of the developing solution is increased, the contact time of the developing solution and the back face of the wafer is effectively shortened, residual glue is prevented from being attached to the wafer again, and therefore the cleanliness of the technology is improved, and the production efficiency is improved. Aiming at a high-viscosity negative photoresist photoetching process used in semiconductor manufacturing, the process stability of uniform photoresist developing equipment is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor technology, and in particular relates to a method for reducing process defects of a coating and developing device. Background Art

[0002] Spreading and developing technology is a key step in semiconductor manufacturing. It is mainly used to form a uniform photosensitive layer on the wafer and perform subsequent photolithography development. The stability of the spreader and developing equipment is crucial to the yield and consistency of semiconductor devices. The existing photolithography process usually includes the following steps:

[0003] Pre-baking: high-temperature baking before applying glue to the wafer to remove residual moisture and other solvents on the surface of the wafer, which helps the photosensitive adhesive to form a uniform film on the surface of the wafer and improve the adhesion of the adhesive layer;

[0004] Glue coating: drip an appropriate amount of photosensitive glue on the surface of the wafer, and evenly cover the surface of the wafer with the photosensitive glue by rotating or other coating methods;

[0005] After the photosensitive adhesive is evenly coated on the wafer surface, it needs to be baked for a certain period of time to stabilize the adhesive layer and cooled in an appropriate low-temperature environment;

[0006] Photolithography exposure, by placing a photolithography mask on a photosensitive resin and using a photolithography machine to expose through the pattern on the mask, the light source irradiates the resin layer, causing the exposure area to change;

[0007] Development: The unexposed parts of negative photoresist will be washed away by the developer during the development process. When the negative photoresist is exposed, the photosensitive groups cause the polymer molecules in the photoresist to cross-link into a network structure, making the exposed area more stable and less soluble, while the unexposed parts are dissolved and removed under the action of the developer.

[0008] During use, the applicant discovered that the above process has the following defects:

[0009] 1. Shadows appear at the edge of the pattern after development: Shadows appear at the edge of the pattern after the wafer is developed, and this phenomenon has a periodic pattern. For example, when the equipment is not used for a long time, the development effect is good, but after concentrated and large-scale use in a short period of time, the effect gradually deteriorates. Even in the same batch of wafers, the development effect of the previous wafers is good, while the subsequent wafers have problems.

[0010] 2. After development, photoresist may be missing from the edge of the wafer, which means that the developer dissolves the photoresist excessively, exposing the wafer substrate.

[0011] 3. When backwash is turned on, residual glue still exists on the back of the wafer after the process is completed, which will have a negative impact on subsequent manufacturing steps;

[0012] The above defects seriously affect the accuracy of the photolithography pattern, resulting in a decrease in production yield, an increase in manufacturing costs, and making it impossible for the existing process of the coating and developing equipment to stably produce high-quality products. Summary of the invention

[0013] In order to overcome the deficiencies of the prior art, an object of the present invention is to provide a method for reducing the process defects of a coating and developing device, so as to solve the problem that the existing use process of the coating and developing device cannot stably produce high-quality products.

[0014] To achieve the above object, the present invention provides the following technical solutions:

[0015] A method for reducing process defects of a coating and developing device, comprising:

[0016] Baking the wafer at high temperature to remove the moisture and solvent remaining on the surface of the wafer, and cooling the wafer after baking and drying;

[0017] Adding photosensitive adhesive to the surface of the cooled wafer to evenly cover the surface of the wafer;

[0018] Baking and stabilizing the photosensitive adhesive layer coated on the surface of the wafer, quickly exhausting the air while baking to discharge byproducts generated by heating the photosensitive adhesive layer inside the baking chamber, and then cooling the wafer and the photosensitive adhesive layer in a low temperature environment;

[0019] Placing a photolithography mask on the photosensitive adhesive layer on the surface of the wafer, and using a photolithography machine to expose the pattern on the photolithography mask;

[0020] Adding a developer to the exposed wafer, letting it stand and then spinning to dry the developer;

[0021] The wafer from which the developer has been dried is cleaned by a rinse agent, and the wafer which is rotating at a high speed is blown dry by nitrogen gas.

[0022] Preferably, the temperature for high temperature baking the wafer is 150-200°C, and the temperature for cooling the wafer is 20-25°C.

[0023] Preferably, the photosensitive adhesive layer coated on the surface of the wafer is baked and stabilized in an environment of 100-115° C., while increasing the gas exhaust rate inside the baking chamber.

[0024] Preferably, the speed of the spin drying developer is 1000-1500 rpm.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention is achieved by:

[0027] The precise developer dripping method is adopted to shorten the moving distance of the dripping liquid and accurately control the dripping time, which significantly improves the loss of glue during the development process, especially the glue stability of the edge of the wafer is significantly improved. By accurately controlling the dripping process, the over-development phenomenon can be effectively avoided, and the stability and repeatability of the development can be improved;

[0028] Increase the exhaust volume inside the baking stabilization chamber to effectively reduce the accumulation of impurities inside the hot plate chamber, and promptly remove the byproducts volatilized by the photosensitive adhesive during the heating process to avoid affecting the uniformity of the heating effect of the photosensitive adhesive layer. By increasing the exhaust volume, impurities can be quickly discharged to ensure the uniformity of the heating process, thereby reducing the formation of shadows;

[0029] Increase the rotation speed of the developer after it has been left to stand, effectively reducing the contact time between the developer and the back of the wafer, preventing residual glue from adhering to the wafer again, and thus improving the cleanliness of the process;

[0030] The improved method proposed in the present invention is aimed at the high-viscosity negative photolithography process used in semiconductor manufacturing, and significantly improves the process stability of the photolithography development equipment. The improved process not only reduces the defects occurring during the photolithography development process and improves the accuracy of the photolithography pattern, but also improves the overall production yield and reduces manufacturing costs. These improvement measures have been tested and verified on existing equipment and have achieved the expected results, and are suitable for various process requirements in semiconductor manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The figure is a block diagram of the improved method of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example:

[0034] See also Figure 1 As shown, a method for reducing process defects of a coating and developing device comprises:

[0035] Baking the wafer at a high temperature of 150 to 200° C. to remove the moisture and solvent remaining on the surface of the wafer, and cooling the wafer at a temperature of 20 to 25° C. after baking and drying;

[0036] Adding photosensitive adhesive to the surface of the cooled wafer to evenly cover the surface of the wafer;

[0037] Baking and stabilizing the photosensitive adhesive layer coated on the surface of the wafer at 100-115° C., rapidly exhausting the air while baking to discharge byproducts generated by heating the photosensitive adhesive layer in the baking chamber, and then cooling the wafer and the photosensitive adhesive layer at a low temperature;

[0038] Placing a photolithography mask on the photosensitive adhesive layer on the surface of the wafer, and using a photolithography machine to expose the pattern on the photolithography mask;

[0039] Adding a developer to the wafer after exposure, and spinning the developer to dry it after standing, wherein the speed of spinning the developer to dry it is 1000-1500 rpm. Within the process allowable range, the speed of spinning the developer to dry it is increased to reduce the residence time of the developer;

[0040] The wafer from which the developer has been dried is cleaned by a rinse agent, and the wafer which is rotating at a high speed is blown dry by nitrogen gas.

[0041] The precise developer dripping method is adopted to shorten the moving distance of the dripping liquid and accurately control the dripping time, which significantly improves the loss of glue during the development process, especially the glue stability of the edge of the wafer is significantly improved. By accurately controlling the dripping process, the over-development phenomenon can be effectively avoided, and the stability and repeatability of the development can be improved;

[0042] Increase the exhaust volume inside the baking stabilization chamber to effectively reduce the accumulation of impurities inside the hot plate chamber, and promptly remove the byproducts volatilized by the photosensitive adhesive during the heating process to avoid affecting the uniformity of the heating effect of the photosensitive adhesive layer. By increasing the exhaust volume, impurities can be quickly discharged to ensure the uniformity of the heating process, thereby reducing the formation of shadows;

[0043] Increase the rotation speed of the developer after it has been left to stand, effectively reducing the contact time between the developer and the back of the wafer, preventing residual glue from adhering to the wafer again, and thus improving the cleanliness of the process;

[0044] The improved method proposed in the present invention is aimed at the high-viscosity negative photolithography process used in semiconductor manufacturing, and significantly improves the process stability of the photolithography development equipment. The improved process not only reduces the defects occurring during the photolithography development process and improves the accuracy of the photolithography pattern, but also improves the overall production yield and reduces manufacturing costs. These improvement measures have been tested and verified on existing equipment and have achieved the expected results, and are suitable for various process requirements in semiconductor manufacturing.

[0045] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0046] In the drawings of the embodiments disclosed in the present invention, only the structures related to the embodiments disclosed in the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other.

Claims

1. A method for reducing process defects of a coating and developing device, characterized in that: include: Baking the wafer at high temperature to remove the moisture and solvent remaining on the surface of the wafer, and cooling the wafer after baking and drying; Adding photosensitive adhesive to the surface of the cooled wafer to evenly cover the surface of the wafer; Baking and stabilizing the photosensitive adhesive layer coated on the surface of the wafer, quickly exhausting the air while baking to discharge byproducts generated by heating the photosensitive adhesive layer inside the baking chamber, and then cooling the wafer and the photosensitive adhesive layer in a low temperature environment; Placing a photolithography mask on the photosensitive adhesive layer on the surface of the wafer, and using a photolithography machine to expose the pattern on the photolithography mask; Adding a developer to the exposed wafer, letting it stand and then spinning to dry the developer; The wafer from which the developer has been dried is cleaned by a rinse agent, and the wafer which is rotating at a high speed is blown dry by nitrogen gas.

2. The method for reducing process defects of a coating and developing device according to claim 1, characterized in that: The temperature of the high temperature baking wafer is 150-200°C, and the temperature of the cooling wafer is 20-25°C.

3. The method for reducing process defects of a coating and developing device according to claim 1, characterized in that: The photosensitive adhesive layer coated on the surface of the wafer is baked and stabilized in an environment of 100 to 115° C., while increasing the gas exhaust rate inside the baking chamber.

4. The method for reducing process defects of a coating and developing device according to claim 1, characterized in that: The speed of the spin drying developer is 1000-1500 rpm.

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