阅读说明：本技术 一种晶圆上动态rrc涂覆节约光刻胶的方法 (Method for saving photoresist on wafer by dynamic RRC coating ) 是由 孙洪君 张晨阳 朴勇男 蔺伟聪 关丽 于 2020-06-24 设计创作，主要内容包括：本发明公开了一种晶圆上动态RRC涂覆节约光刻胶的方法,属于半导体光刻技术领域。该方法针对优化配方,节约光刻胶,降低工艺成本,减少显影缺陷,具有重要意义。在涂胶工艺配方,滴胶步骤前,增加动态RRC涂覆步骤,与现有技术相比,节约了光刻胶,降低了工艺成本,在保证原有标准要求的前提下,提高了工艺质量,并减少了后续显影缺陷,起到降本增质的作用。(The invention discloses a method for saving photoresist on a wafer by dynamic RRC coating, belonging to the technical field of semiconductor photoetching. The method has important significance in optimizing the formula, saving photoresist, reducing the process cost and reducing the development defects. Compared with the prior art, the dynamic RRC coating step is added before the glue dripping step in the glue coating process formula, so that the photoresist is saved, the process cost is reduced, the process quality is improved on the premise of ensuring the original standard requirement, the subsequent development defect is reduced, and the effects of reducing cost and improving quality are achieved.)

1. A method for saving photoresist on a wafer by dynamic RRC coating is characterized in that: the method is used for coating photoresist on a wafer, and specifically comprises the following steps:

(1) sending the 12-inch wafer to be glued into a gluing unit;

(2) performing dynamic photoresist thinner RRC coating;

(3) coating photoresist, wherein the consumption of the photoresist is 2-5 ml;

(4) adjusting the rotating speed of the wafer according to the requirement on the film thickness;

(5) and after the coating of the wafer is finished in the coating unit, the wafer is taken out by a robot, baked, sent to be exposed and developed, and finally the processed wafer is transferred back to the wafer box.

2. The method for dynamic RRC coating photoresist on a wafer according to claim 1, wherein: in the step (2), in the dynamic RRC coating process, the RRC coating time is determined according to the thickness, the characteristics and the like of the photoresist spin-coated on the wafer.

3. The method for dynamic RRC coating photoresist on a wafer according to claim 1, wherein: in the step (2), the RRC coating time is 2-10s, and the wafer rotating speed is 20-50 rpm.

4. The method for wafer dynamic RRC coating photoresist saving according to claim 1, wherein: in the step (3), the consumption of the photoresist is determined according to the thickness, characteristics and the like of the photoresist spin-coated on the wafer.

Technical Field

The invention relates to the technical field of semiconductor photoetching, in particular to a method for saving photoresist by dynamic RRC coating on a wafer.

Background

Semiconductor lithography processes are also continually advancing as the technology for manufacturing semiconductor integrated circuits and devices continues to advance and evolve. With the decreasing of the critical dimension of the device, the process cost is also increasing, so that the reduction of the process cost and the reduction of the photoresist consumption become more important. Reasons include, but are not limited to, the following: 1. to produce smaller and higher density circuits, multiple layers of photoresist are coated on a 12 inch (300mm) wafer, the amount of photoresist required is large, and the price of each layer of photoresist is expensive, so that the cost price of producing chips is higher and higher; 2. in the production process, the CP value of some photoresist is large, the photoresist is not easy to spread on the surface of the whole wafer uniformly during spin coating, so that photoresist in partial areas is accumulated, and the accumulation can cause serious influence on subsequent etching and other processes; 3. in the wafer coating process, micro bubbles invisible to naked eyes exist in the photoresist, which can affect subsequent etching and other processes.

For the above reasons, it is important to reduce the amount of photoresist used for the stacked coating of multiple layers of photoresist on a wafer because the amount of photoresist required is large and the price of each layer of photoresist is expensive. The RRC is used as a photoresist solvent, so that in the process of coating (see figure 1), the use amount of the photoresist can be reduced, the photoresist can be diluted, the mobility of the photoresist is increased, microscopic bubbles contained in the photoresist are reduced, the photoresist is uniformly coated on the surface of a wafer (see figure 2), and the RRC has an obvious optimization effect on subsequent processes such as development, etching and the like.

At present, in the process method of photoresist coating on the wafer, a dynamic RRC coating step is rarely added, and the advantages and the disadvantages are that:

the advantages of no RRC coating step during coating are: 1. the process time can be saved, and the productivity is relatively improved; 2. the RRC-free coating enables the mechanical structure and the control program of the gluing equipment to be relatively simple, the failure rate of the equipment can be relatively reduced, and the equipment cost is saved. The disadvantages are that: 1. the consumption of the photoresist is relatively large, so that the production process cost is increased; 2. the subsequent processes such as development, etching and the like have more defects, the process yield is low, and the requirements of high-performance integrated circuit devices cannot be met.

Disclosure of Invention

In order to solve the problems of large consumption of photoresist, high cost, more subsequent process defects and low process yield in the prior art, the invention aims to provide a method for saving photoresist by dynamic RRC coating on a wafer.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for saving photoresist on a wafer by dynamic RRC coating is used for coating the photoresist on the wafer and specifically comprises the following steps:

(1) sending the 12-inch wafer to be glued into a gluing unit;

(2) performing dynamic photoresist thinner RRC coating; RRC coating time is 2-10s, and wafer rotating speed is 20-50 rpm.

(3) Coating photoresist, wherein the consumption of the photoresist is 2-5 ml;

(4) adjusting the rotating speed of the wafer according to the requirement on the film thickness;

(5) and after the coating of the wafer is finished in the coating unit, the wafer is taken out by a robot, baked, sent to be exposed and developed, and finally the processed wafer is transferred back to the wafer box.

In the step (2), in the dynamic RRC coating process, the RRC coating time is determined according to the thickness, the characteristics and the like of the photoresist spin-coated on the wafer.

In the step (3), the consumption of the photoresist is determined according to the thickness, characteristics and the like of the photoresist spin-coated on the wafer.

The invention has the following advantages and beneficial effects:

1. the method of the invention utilizes the glue coating process formula, adds dynamic RRC coating before the glue dripping step, greatly reduces the usage amount of photoresist, reduces the process cost, improves the process quality on the premise of ensuring the original standard requirement, simultaneously reduces the subsequent development defect and improves the process yield.

2. The process quality is improved: the RRC is used as a photoresist solvent, so that the mobility of the photoresist is increased, microscopic bubbles contained in the photoresist are dissolved, the photoresist can be more uniformly coated on the surface of the wafer, the subsequent processes such as development, etching and the like are obviously optimized, the process yield is improved, and the requirement of a high-performance integrated circuit device can be met.

3. For the photoresists with different components and thicknesses, the conditions for realizing the optimal coating effect (observed by a photoresist film thickness change curve obtained by measuring a coated optical film thickness gauge) can be searched by adjusting parameters such as increasing or reducing the time length of an RRC coating step, RRC supply flow, pressure and the like.

Drawings

FIG. 1 is a schematic view of the coating process of the present invention.

FIG. 2 is a schematic diagram showing the distribution of RRC and photoresist on the wafer surface during the coating process.

Detailed Description

The invention is described in detail below with reference to the figures and examples.

The invention provides a method for saving photoresist by dynamic RRC coating on a wafer, which comprises the following specific processes:

taking out a 12-inch wafer to be coated with glue from a wafer box, conveying the wafer to a cold plate for cooling at 23 ℃, then conveying the wafer to a gluing unit for gluing, selecting a gluing formula for preparing to coat the photoresist, wherein the consumption of the photoresist is 10-20ml before an RRC step is not added;

secondly, modifying a gluing formula, adding a dynamic RRC coating step before a glue dripping step, and setting RRC coating time to be 2-10s, wherein the rotating speed is generally 20-50rpm (the specific RRC coating time is determined according to the thickness, the characteristics and the like of photoresist spin-coated on a wafer);

thirdly, coating the photoresist, wherein the consumption of the photoresist is 2-5ml and is far less than that of the photoresist used before the RRC step is not added (the specific consumption of the photoresist is determined according to the thickness, the characteristics and the like of the photoresist spin-coated on the wafer);

fourthly, after RRC coating is finished, photoresist coating is carried out, and the film thickness is adjusted through the main rotating speed;

and fifthly, after the coating process of the wafer is finished in the glue coating unit, taking out the wafer by a robot, baking, exposing, developing and finally transferring the processed wafer back to the wafer box.