JPS6410596B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an etching apparatus, and more particularly to a semiconductor substrate etching apparatus for etching a semiconductor substrate using a constant temperature chemical solution.

In the conventional etching tank, as shown in FIG. 1, a solution 3 kept at a constant temperature in a cooler 2 is circulated through the outer wall of the etching tank 1 to keep the temperature of the chemical solution 4 in the etching tank 1 constant. With this method, for example, when a semiconductor substrate is etched with a mixed chemical solution of hydrofluoric acid, nitric acid, and glacial acetic acid, the temperature of the mixed chemical solution rises due to the reaction heat of the etching. Even if etching is carried out on the outer wall of the etching tank 1, the heat of reaction is large, so it takes a long time to bring the mixed chemical solution 4 to a constant temperature, making it impossible to perform continuous etching of semiconductor substrates, and thus not being able to be used as a mass production device. Ta. Another possible method is to directly pass the chemical solution 4 through the cooler 2 as shown in FIG. 2, but it is not possible to use a highly corrosive chemical solution like the mixed chemical solution described above.

In order to eliminate these drawbacks, the present invention involves, for example, a Teflon pipe or the like being wrapped in the etching tank, and a liquid for the purpose of constant temperature is introduced into the pipe, so that even if the temperature rises due to the reaction heat of the etching process of the chemical liquid, the chemical liquid can be kept at a constant temperature. The present invention provides an etching apparatus that facilitates constant temperature control and enables continuous etching of semiconductor substrates.

The present invention is characterized by an etching bath for containing a chemical for etching semiconductor substrates, an outer bath surrounding the etching bath to keep the chemical at a constant temperature, and a corrosion-resistant pipe located inside the etching bath. The pipe in the etching tank is installed along the inner wall of the tank from the lower part to the upper part in the peripheral part of the etching tank except for the central part, and the pipe is provided with a cooler. and the pipe in the etching tank are connected by a first connecting pipe that passes through the outer tank, through which a liquid for constant temperature of the chemical solution is sent from the cooler and passes through the pipe in the etching tank. A liquid for constant temperature of the chemical solution is made to flow from the upper part of the etching tank into the outer tank, and a second pipe connects the bottom of the outer tank and the cooler to keep the chemical solution constant. A semiconductor substrate etching apparatus is provided in which a constant temperature liquid is returned to the cooler.

The present invention will be explained in detail below with reference to the drawings.

3 and 4 are schematic diagrams showing embodiments of the present invention, respectively, in which 1 is an etching tank, 2 is a cooler, 3 is a constant temperature liquid, 4 is hydrofluoric acid, nitric acid,
It is a mixed chemical solution of glacial acetic acid. Reference numeral 5 denotes a Teflon pipe through which a constant-temperature solution passes, and this pipe consists of a pipe 5' in the etching tank, a first connecting pipe 5'', and a second connecting pipe 5.

In this embodiment, the liquid 3 that has been kept at a constant temperature by the cooler 2 is introduced into a Teflon pipe, passes through a first connecting pipe 5'' and a pipe 5' in the etching tank 1, and is then kept at a constant temperature of the mixed chemical solution 4. The chemical mixture 4 returns to the cooler through the second connecting pipe 5 and is circulated.The effect of this structure is that the mixed chemical solution 4 is Even if the temperature rises due to processing reaction heat,
Since heat exchange between the temperature-controlled solution 3 and the mixed chemical solution 4 takes place on the outer wall of the etching tank and the surface area of the Teflon pipe, it becomes easy to maintain the temperature of the chemical solution 4, allowing continuous etching of semiconductor substrates. It is. That is, since the chemical solution is kept at a constant temperature from both the pipe and the outer tank, its efficiency and speed are high, and the treatment can always be carried out at a predetermined temperature. In addition, this liquid for constant temperature flows out from the pipe to the outer tank, and from there it is returned to the cooler through the second pipe, so there is no need to prepare separate liquid for the outer tank and for the inner tank pipe. . Furthermore, as shown in Figures 3 and 4, the pipes are arranged in the inner tank along the inner wall of the tank from the lower part to the upper part at the periphery excluding the central part. There is. The above-mentioned efficiency is further promoted by being provided from the lower part to the upper part in this manner.
Further, by providing a pipe in the peripheral part except for the central part, it is possible to immerse the semiconductor substrate in this central part and perform etching. Moreover, the liquid whose temperature is constant by the cooler is passed through the outer tank.
is introduced into the pipe in the etching tank through the connecting pipe. Therefore, due to this first connecting pipe, that is, the liquid flowing through the first connecting pipe, which is kept at a constant temperature at a predetermined temperature, also brings the liquid accumulated in the outer tank closer to the predetermined temperature. I can do it. As a result, the temperatures of both the pipes inside the bath and those from the outer bath can be maintained at closer temperatures, so that the temperature of the etching solution can be maintained efficiently from this point of view as well.

As explained above, the present invention has many advantages over conventional methods. In the embodiments of the present invention, a Teflon pipe was wound into a spiral structure and used in the process of etching a semiconductor substrate with a mixed chemical solution of hydrofluoric acid, nitric acid, and glacial acetic acid. As long as it has a structure in which a corrosion-resistant pipe is wrapped around the chemical solution in a state capable of processing non-processed materials for the purpose of constant temperature in the etching tank,
Needless to say, the scope of the claims of this patent extends regardless of the material or process.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic diagrams of a conventional etching apparatus, respectively, and FIGS. 3 and 4 are schematic diagrams showing an embodiment of the present invention, respectively. In the figure, 1... etching tank, 2...
Cooler, 3... Constant temperature liquid, 4... Mixed chemical solution of hydrofluoric acid, nitric acid, and glacial acetic acid, 5... Teflon pipe for passing the constant temperature liquid, 5'... Pipe in the etching tank, 5''... ...first connection pipe, 5...second
This is the connecting pipe. Further, the arrows in the figure indicate the flow of the constant temperature liquid.

Claims (1)

[Claims] 1. An etching tank for containing a chemical for etching semiconductor substrates, an outer tank surrounding the etching tank to keep the temperature of the chemical solution constant, and a corrosion-resistant pipe located inside the etching tank. The pipes inside the etching tank are installed along the inner wall of the tank at the periphery of the tank, excluding the central part, from the lower part to the upper part. The pipe is connected to a first connecting pipe that penetrates the outer tank, and a liquid for constant temperature of the chemical liquid is sent from the cooler to this pipe, and the chemical liquid that has passed through the pipe in the etching tank is kept at a constant temperature. The liquid for making the chemical liquid flow out from the upper part of the etching tank into the outer tank, and the bottom part of the outer tank and the cooler are connected by a second pipe to supply the liquid for constant temperature of the chemical solution. A semiconductor substrate etching apparatus characterized in that the semiconductor substrate is returned to the cooler.