JPH0311885Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a developing device for semiconductor wafers.

(Prior Art) Development is one of the photoetching processes in the manufacturing process of semiconductor integrated circuits. This refers to the process of dissolving the unexposed resist, using a solvent that dissolves low-polymerization substances but not high-polymerization substances, and either spraying this on the wafer or, if necessary, applying a rinse solution after spraying the solvent. This is done by spraying.

Normally, when spraying chemicals such as solvents and cleaning solutions onto the wafer in this type of development process, the chemicals are sealed in a container such as a canister, and a suitable gas such as nitrogen gas is supplied inside to increase the internal pressure. This allows the chemical solution to be discharged from the container and distributed onto the wafer rather than by spraying.

However, according to such means, as the chemical solution is used, the liquid level inside the container gradually decreases.
On the other hand, since the pressure of the gas supplied inside the container has conventionally been kept constant, the discharge pressure of the chemical liquid gradually decreases, resulting in a decrease in the amount of the chemical liquid discharged from the container.

In order to avoid this, it is possible to increase the gas pressure in advance to the extent that a predetermined discharge pressure can be maintained even if the chemical solution in the container becomes low, but according to this method, a large amount of chemical solution remains. Even in this case, because the gas pressure is high, the chemical solution is discharged in excess of the required amount and is wasted. Furthermore, variations in the discharge conditions occur, such as the discharge pressure changing depending on the amount of remaining chemical solution.

It has also been considered to detect the flow rate of the chemical liquid from the container and control the gas pressure depending on the flow rate so that the flow rate is always constant. However, according to this method, it is not possible to predict that the remaining amount will reach zero, and it becomes clear that the remaining amount has reached zero only when the flow rate reaches zero. In such cases, the process must be stopped midway through development.
This is extremely inconvenient.

(Problems to be solved by the invention) This invention aims to keep the discharge pressure constant regardless of the amount of chemical liquid remaining in the container, and displays the remaining amount of chemical liquid in the container. To make it possible to know in advance when the remaining amount of a chemical solution in a container becomes zero.

(Means for solving the problem) This invention uses a scale to sequentially detect the remaining amount of the chemical solution in the container, which decreases as the spraying of the chemical solution progresses. The device is characterized in that the pressure of the gas for discharging the chemical solution supplied to the inside of the container is adjusted based on the emitted signal, and the remaining amount of the chemical solution in the container is indicated using the above-mentioned scale.

(Example) An example of this invention will be described with reference to the drawings. Reference numeral 1 denotes a wafer, and a chemical solution used for development is sprayed onto the surface of the wafer from a spray 2. The wafer 1 is held by a vacuum chuck 3 and rotated by a rotating shaft 4. 5 is a container in which a chemical solution 6 (e.g., developer, cleaning solution, etc.) necessary for developing work is stored; 7 is a pipe for the chemical solution disposed between the container 5 and the spray 2; and 8 is a container in which a gas is stored in the container 5. This is a pipe that supplies (for example, an inert gas such as nitrogen gas) for discharging a chemical solution. These configurations are not particularly different from conventional devices of this type.

According to this invention, as a device for detecting the remaining amount of the chemical solution 6 in the container 5 without opening the container,
Use scale 9. Then, the container 5 is placed on the scale 9. Since the chemical solution 6 becomes lighter as it is used, the remaining amount of the used chemical solution can be determined from the scale 10 of the scale 9.

To detect this remaining amount, a plurality of detector positions 2 for detecting the position of the pointer 11 are arranged along the scale 10 as shown in the figure. As this detector, it is preferable to use a photosensor, for example, one constructed by a combination of a photodiode and a phototransistor.

For example, a pressure regulator 13 with a motor drive is arranged on the pipe 8 . 14 is a pressure sensor.

In the above configuration, it is assumed that the pressure of the supplied gas is adjusted by the pressure regulator 13 so that a pressure corresponding to the amount of the chemical liquid 6 in the container 5 is initially applied. It is assumed that the pressure at this time causes the discharge pressure of the chemical solution 6 from the container 5 to be within a predetermined range.

As the amount of chemical solution 6 in container 5 decreases as the development of the wafer progresses, the indicated value of scale 9 becomes smaller. When one detector 12 detects the position of the pointer 11 when the pressure has decreased by a certain amount, the pressure regulator 13 is operated based on the detection signal to increase the gas pressure.

This pressure is detected by the pressure sensor 14, and is increased until it reaches a value suitable for generating a predetermined discharge pressure for the amount of chemical solution 6 in the container 5 at that time. Repeat this below. This ensures that the fluid is always discharged at the optimum discharge pressure.

Further, as the development progresses, it is possible to predict when the remaining amount will reach zero based on the remaining amount when the chemical solution in the container 5 decreases. Therefore, it is possible to avoid a situation where the process has to be stopped midway due to the chemical solution in the container 5 dropping to zero during the development process.

(Effects of the invention) As detailed above, according to this invention, the amount of chemical liquid discharged can be stabilized and sprayed onto the wafer with the optimal discharge pressure at all times, and there is no wasteful spraying. Furthermore, it is possible to know in advance when the remaining amount becomes zero.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of this invention, and FIG. 2 is a plan view of the scale. 1... Wafer, 2... Spray, 5... Container, 6... Chemical solution, 9... Scale, 10... Scale, 11
... pointer, 12 ... detector, 13 ... pressure regulator.

Claims (1)

[Scope of Claim for Utility Model Registration] A container in which a chemical solution for wafer development is stored; a sprayer that sprays the chemical solution onto the wafer, which is discharged by the pressure of gas supplied into the container; a scale on which the container is mounted, a scale having a pointer and a scale indicating the remaining amount of the chemical solution in the container as the chemical solution is being sprayed; and a plurality of scales arranged along the scale of the scale; a detector that sequentially detects the pointers that are displaced as the spraying of the chemical solution progresses and outputs a signal; In order to increase the pressure of the gas and keep the discharge pressure constant, a pressure regulator is provided that adjusts to increase the pressure of the gas supplied into the container in sequence according to signals from each of the detectors. A developing device for semiconductor wafers, characterized by comprising: