JP2692042B2 - Processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a processing apparatus.

(Prior Art) For example, in a semiconductor device manufacturing apparatus, a resist coating step is indispensable as one of the photolithography steps. This coating apparatus is a so-called spin coating, in which a resist solution consisting of a resist and its solvent is dropped onto a semiconductor wafer and the semiconductor wafer is rotated in one direction to form a resist film of a uniform thickness on the semiconductor wafer. It is called a device.

At this time, it is important to exhaust the atmospheric gas in the cup surrounding the semiconductor wafer and to control the exhaust flow rate thereof, which is disclosed in JP-A-57-166033 and JP-A-58-17.
8522, JP-A-60-245225. That is, when the atmosphere gas is not exhausted and the exhaust gas flow rate is not controlled, the resist film cannot be formed uniformly due to uneven coating of the resist solution, adhesion of foreign matter in the atmosphere gas, and the like. The film thickness control is also hindered. So, connect the exhaust pipe to the cup,
The atmosphere gas in the cup is exhausted through this exhaust pipe, and based on the output of the flow rate detection unit provided in the middle of the pipe,
It is necessary to control the exhaust flow rate.

(Problems to be Solved by the Invention) Thus, exhausting the atmospheric gas in the cup,
It has been found that controlling the exhaust flow rate and the exhaust flow rate are greatly related to the improvement of the processing yield of the semiconductor wafer, and the control accuracy of the exhaust flow rate depends on the flow rate detection accuracy.

By the way, as a result of the inventors of the present invention studying the yield improvement measure, the detection accuracy decreases over time in view of the peculiarities of the exhaust gas, and therefore the exhaust flow rate control accuracy extremely decreases, or undetectable occurs, and the yield increases. It turned out to fall. That is, it has been clarified that this kind of exhaust gas is a gas-liquid mixture, and the foreign matter in the exhaust gas adheres to the detection portion, resulting in extremely low detection accuracy.

Therefore, it is an object of the present invention to provide a processing device capable of realizing highly accurate exhaust control by preventing foreign matter from adhering to a detection unit that detects the exhaust flow rate of a gas-liquid mixture. .

[Structure of the Invention] (Means for Solving the Problems) The processing apparatus according to the invention of claim 1 is a processing apparatus that performs a predetermined process while exhausting a gas-liquid mixture, and the processing container and the processing container. An exhaust line connected to the exhaust line for performing the exhaust, and a flow rate detection unit provided in the exhaust line,
It is characterized in that the apparatus further comprises means for trapping unnecessary substances in the exhaust atmosphere, which is provided in a stage preceding the flow rate detecting section.

According to a second aspect of the present invention, in the processing apparatus according to the first aspect, the trapping means is a mesh.

(Operation) According to each of the first and second aspects of the present invention, by providing a means for trapping an unnecessary object in the preceding stage of the flow rate detection unit, foreign matter is prevented from adhering to the flow rate detection unit, and the flow rate control accuracy thereof is improved. Trying to improve.

In addition, it is possible to prevent a change in exhaust speed that occurs when the flow rate detection unit is not protected and adverse effects on the process due to erroneous detection. In addition, failure of the flow rate detection unit can be prevented.

In particular, according to the second aspect, by configuring the trapping means with a mesh, the mesh functions as a filter for capturing the foreign matter, so that the flow rate detection unit can be reliably protected.

The trap means may be composed of, for example, a mist trap provided in the exhaust line and a mesh for trapping the powder solidified by the mist trap in the middle of the flow rate between the flow rate detection sections. In this case, for example, a mist-like solution (mist) in the gas-liquid mixture as the exhaust gas is captured by the mist trap provided on the upstream side of the exhaust passage. However, the mist trap alone cannot prevent foreign matter from adhering to the flow rate detector. The mist captured by the mist trap is solidified with time, becomes powder, and is exhausted to the flow rate detection unit side together with the exhaust gas.
Then, the powder flowing out from the mist trap adheres to the flow rate detection unit, which greatly reduces the accuracy of exhaust flow rate control. As described above, by configuring the trap means with the mist trap and the mesh on the downstream side thereof, the accuracy of exhaust flow rate control can be improved.

(Example) Hereinafter, one example in which the present invention is applied to a resist coating apparatus for a semiconductor wafer will be specifically described with reference to the drawings.

In FIG. 1, a spin chuck 12 for mounting and fixing the semiconductor wafer 10 is provided, and this spin chuck 12 can be rotationally driven in the direction of the arrow in the figure. This spin chuck
A resist nozzle 14 is provided above the substantially central position of the semiconductor wafer 10 placed on the wafer 12. The resist nozzle 14 is capable of dropping a predetermined amount of resist solution including a resist and its solvent onto the semiconductor wafer 10 at a substantially central position. The semiconductor wafer 10 and spin chuck
A cup 16 is provided so as to surround 12. Since the cup 16 is coated with the resist on the semiconductor wafer 10 by rotating the spin chuck 12, it serves to prevent the resist solution from being scattered to the outside by a centrifugal force. A drain 18 is connected to the bottom of the cup 16 so that excess resist liquid can be drained.

Further, an exhaust pipe 20 is connected to the bottom of the cup 16 so that the atmospheric gas in the cup 16 can be exhausted when the resist is applied.

Next, the exhaust system will be described. A mist trap 22 is provided on the upstream side of the exhaust pipe 20. The mist trap 22 includes a plurality of partition walls 22a that meander the exhaust passage.
have. Exhaust gas comes into contact with and traps the partition wall 22a. This Mist Trap 22
A valve 24 is provided downstream of the valve 24. By opening and closing the valve 24, on / off of the exhaust operation in the exhaust pipe 20 can be controlled. The valve 24 can be provided at any position between the exhaust pipes 20.

On the downstream side of the valve 24, a protective mesh 26, which is an example of a filter that captures foreign matter that has passed through the trap 22, is provided. The protective mesh 26 traps foreign matter of a predetermined size or more in the exhaust gas that has passed through the mist trap 22 in its mesh. The filter is not limited to the protective mesh 26, and may have a function of filtering a powdery material such as a porous material.

The exhaust pipe 20 on the downstream side of the protective mesh 26 is provided with a detector 28 for detecting the exhaust flow rate and a variable damper 32 for variably controlling the exhaust flow rate. A mass flow controller 30 is provided for inputting the output from the detection unit 28 and controlling the variable damper 32 based on the detected output. In the present embodiment, the variable damper 32 is drive-controlled based on the detection output of the detection unit 28 so that the exhaust flow rate is always constant.

 Next, the operation will be described.

After the semiconductor wafer 10 is mounted and fixed on the spin chuck 12, a predetermined amount of resist solution is dropped from the resist nozzle 14 and the spin chuck 12 is rotationally driven at a constant rotation speed in the arrow direction of FIG. As a result, the resist liquid dripped at the substantially central position of the semiconductor wafer 10 diffuses on the semiconductor wafer 10 in the peripheral direction by the rotation of the spin chuck 12, and the resist coating is performed on the entire surface of the semiconductor wafer 10. It will be.

During this resist coating, coating unevenness on the surface of the semiconductor wafer 10 and a reflection phenomenon in which resist particles scattered in the cup 16 adhere to the semiconductor wafer occur, and these are exhausted from the atmospheric gas inside the cup 16. It depends on the fluctuation of the flow rate. In the present embodiment, by improving the detection accuracy in the detection unit 28 in the middle of the exhaust pipe 20, it is possible to prevent the fluctuation of the exhaust flow rate,
The resist is applied with high yield.

That is, the exhaust gas exhausted through the exhaust pipe 20 is
First, it is introduced into the mist trap 22. Since a plurality of partition walls 22a are formed inside the mist trap 22 so as to meander the exhaust gas flow rate, when the exhaust gas collides with the partition walls 22a, mist that is a mist-like solution is generated. The partition wall 22a captures the solution in the gas-liquid mixture as exhaust gas, which can be reliably trapped.

According to the experiments conducted by the present inventors, it has been confirmed that the provision of only the mist trap 22 in the middle of the exhaust pipe 20 cannot prevent foreign matter from adhering to the detection unit 28. That is, it was confirmed that the mist once captured by the mist trap 22 solidifies into powder over time, and the powder separates from the partition wall 22a and flows into the downstream side of the mist trap 22 together with the exhaust gas. . Therefore, in this embodiment, this mist trap 22
A protective mesh 26 is arranged midway between the exhaust pipe 20 and the detector 28. By providing this protective mesh 26,
It is possible to reliably capture the foreign matter originally present in the exhaust gas and the powder that is once captured by the mist trap 22 and then solidifies and flows out. Therefore, in the detection unit 28 provided in the subsequent stage of the protective mesh 26, the exhaust gas from which foreign substances such as mist and powder have been removed in advance passes, so that the foreign substances adhere to the detection unit 28 more than before. It is possible to significantly reduce it. As a result, the detection unit 28
With, it becomes possible to detect the exhaust flow rate with a predetermined accuracy at all times.
By outputting this information to the mass flow controller 30 and driving the variable damper 32 that variably controls the exhaust flow rate based on the drive of the mass flow controller 30, the cup 16
Fluctuations in the exhaust flow rate of the atmospheric gas inside can be greatly reduced.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

For example, the mist trap 22 is a partition wall in the above embodiment.
Although the exhaust flow amount is formed to meander by 22a, the present invention is not limited to this. Further, as the filter constituted by the protective mesh 26, various filter means capable of capturing foreign matter having a size equal to or larger than a predetermined particle size can be adopted. Also,
As the arrangement position, the mist trap 22 and the detector 28
It suffices as long as it exists in the midway 20 of the exhaust pipe between and, and for example, a filter can be integrally attached to the outlet of the mist trap 22. Like this, mist trap
By attaching the filter integrally with the 22, it is possible to simplify maintenance work such as cleaning.

Furthermore, the present invention is not limited to the application to the resist coating apparatus in the manufacturing process of the semiconductor element as in the above-mentioned embodiment, at least the gas-liquid mixture is exhausted, and if the processing is performed while controlling the exhaust flow rate, It can be similarly applied to other processing devices.

[Effects of the Invention] According to each of the first and second aspects of the present invention, by providing a means for trapping an unwanted substance in the preceding stage of the flow rate detection unit, the adhesion of foreign matter to the detection unit is significantly reduced compared to the conventional case. It is possible to prevent fluctuations in the exhaust gas flow rate by improving the detection accuracy, and it is possible to significantly improve the yield of processing, for example.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a resist coating apparatus to which the present invention is applied. 10 ... Non-processed object (semiconductor wafer), 12 ... Spin chuck, 14 ... Resist nozzle, 16 ... Cup, 20 ... Exhaust pipe, 22 ... Mist trap, 26 ... Filter (protective mesh), 28 ……Detection unit.

Claims (2)

(57) [Claims] 1. A processing apparatus for performing a predetermined process while exhausting a gas-liquid mixture, a processing container, an exhaust line connected to the processing container for performing the exhaust, and a flow rate detection unit provided in the exhaust line. A processing apparatus, characterized in that it comprises means for trapping unnecessary substances in the exhaust gas atmosphere, which is provided in a stage preceding the flow rate detecting section. 2. The processing apparatus according to claim 1, wherein the trapping means is a mesh.