JPS622543A - Decomposing device for semiconductor thin film - Google Patents

Abstract

PURPOSE:To obtain a safe and handy decomposing device for thin film by a method wherein the seal container thereof holding the wafer container and so forth is provided with an air feed opening and a liquid feed opening or an air feed opening also serving as a liquid feed opening, and at the same time is provided with an exhaust vent and a light discharge opening; and the liquid is injected and discharged by the operation of the valves. CONSTITUTION:Semiconductor substrates W each having thin films (f) are loaded in a wafer carrier 3 in a state that the substrates W are erected, and then a carrier cover 6 is put over. By opening a valve 11, hydrofluoric acid is injected in an air feed opening also serving as a liquid feed opening 10 at the prescribed amount and the hydrofluoric acid L is injected in liquid reservoirs 7c in a seal container 7 up to the prescribed liquid level. After that, a cover 7a is closed, and at the same time the valve 11 is also closed to seal the container 7, which is left to stand for the prescribed time; and after an elapse of the prescribed time, a liquid discharge opening 8 is connected to the waste liquor tank and so forth, and after that a valve 9 is opened to discharge the hydrofluoric acid L of the liquid reservoirs 7c. An exhaust vent 12 is connected to the exhaust duct, and a valve 13 is opened to exhaust the hydrogen fluoric gas of the container 7. The valve 11 is opened to feed the air into the container 7 through the opening 10, with the result that the gas inside is substituted for the air. After that, pure water is injected in the container 7 through the opening 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a decomposition device for decomposing a thin film of Ml oxide or the like formed on a semiconductor substrate.

[Technical Background of the Invention J] In a thin film such as an oxide film formed on a semiconductor substrate, Na,
It is well known that if an impurity such as Fe is contained, even if the amount is extremely small, it will have a large effect on the electrical characteristics of a semiconductor element. Therefore, in order to improve the electrical characteristics of the device, it is necessary to accurately grasp the content of these impurities and to suppress the incorporation of the impurities as much as possible when forming the thin film.

Conventionally, a decomposition apparatus having the structure shown in FIG. 2 has been used to decompose a thin film on a semiconductor substrate and measure the impurity content therein.

In FIG. 2, 1 is a closed container having a lid 1a;
Applicable W! Inside the closed container 1, there is hydrogen fluoride 11! A beaker 2 containing L, a wafer carrier 3 containing a semiconductor substrate W in an upright state, and a support stand 4 that supports the wafer carrier 3.
, a decomposition liquid receiver 5 supported by the support stand 4 and placed directly below the wafer carrier 3, and a clear rear cover 6 placed over the top of the wafer carrier 3.

When decomposing 1llaf on the semiconductor substrate W with this apparatus, it is left in the illustrated state at room temperature for several hours. Then, the wimr is decomposed by the hydrogen fluoride vapor generated from the hydrogen fluoride WIL to become a decomposition liquid l, and this decomposition liquid l
will accumulate in the decomposition liquid receiver 5, so open Ila after opening for a predetermined time and transfer the decomposition liquid l from the decomposition liquid receiver [15] to another container (test tube, etc.) using a micropipette, etc. The sample is weighed as soon as it is soaked, and the amount of impurities in the decomposed liquid is measured using a flameless atomic absorption spectrometer.

For use, a mixed acid consisting of iAMSmM fluoride water and water is placed in the container 1, and the container is heated at about 90°C on a hot plate.
After heating and washing, the container is tilted to flush out the mixed acid, and then washed with pure water to prepare for the next decomposition operation.

[Problem 1 of Background Art The conventional decomposition V;l arrangement as described above has the following problems.

(a)i! When the lid is opened after Il1 decomposition is completed, the inside is filled with
There was a danger that the hydrogen fluoride gas that was in the tank would leak out and be inhaled by the measurement workers, so improvements were needed for safety and health reasons.

(b) Since a person has to hold the beaker 2 by hand to put in and take out the hydrofluoric acid, it is not desirable in terms of safety and health, and the operation is troublesome.

(0) It was dangerous to handle heated strong acid when cleaning the inside of the closed container 1 after use. In particular, when pouring out the heated strong acid from inside the container, there was a risk that the strong acid would scatter, which was very dangerous.

[Object of the Invention] An object of the present invention is to solve the above-mentioned problems and provide an improved disassembly device. In other words, an object of the present invention is to eliminate the need for a person to manually take a beaker containing hydrofluoric acid into and out of the container at the start and end of a decomposition operation, and to eliminate harmful gases at the end of a decomposition operation. An object of the present invention is to provide an improved decomposition device in which there is no risk of strong acid being scattered around, and furthermore, there is no risk of strong acid being splashed during cleaning of the container.

[Summary of the Invention 1] In the improved decomposition apparatus according to the present invention, an air supply port, a liquid supply port,
Alternatively, an air supply port and liquid supply port is provided, an exhaust port and a liquid drain port are provided, and a valve is provided at the air supply port, liquid supply port, air supply port and liquid supply port, exhaust port, and liquid drain port. The present invention is characterized in that ventilation within the container and operations for injecting and draining liquid into the container can be performed by operating the valve. According to the apparatus of the present invention having such a configuration, the above-mentioned problems are solved and a disassembly apparatus that is safe and easy to handle is realized.

[Embodiment 1 of the invention An embodiment of the present invention will be described below with reference to FIG.

, J3, parts having the same configuration as those of the conventional apparatus are designated by the same reference numerals as those shown in FIG. 2, and therefore, explanations of these parts will be omitted.

In the embodiment of the present invention shown in FIG. 1, a bottom plate of a closed container 7 having a lid 7a is formed with a high island-shaped platform 7b in the center thereof. A support stand 4, a decomposition liquid receiving tray 5, and a wafer carrier 3 are placed on the portion 7b. Further, an annular liquid reservoir 7c is formed surrounding the platform portion 7b, and hydrogen fluoride acid is stored in this liquid reservoir 7c. A drain port 8 communicating with the liquid reservoir 7C is provided on the side wall near the bottom of the container 7, and a valve 9 is also provided. Further, an air supply port/liquid supply port 10 and a valve 11 are provided on the side wall above the liquid reservoir 7C, and an exhaust duct (not shown) is provided on the side wall near the top of the container 7. A connecting exhaust port 12 is provided and a valve 13 is provided.

When using the device of the present invention as described above, first, the thin IQ
After loading the semiconductor blocking plate W having the shape r into the wafer carrier 3 in an upright state, the carrier cover 6 is covered.
Next, the valve 11 is opened and a predetermined amount of hydrofluoric acid is injected into the air supply port/liquid supply port 10, and hydrogen fluoride 1@! is injected into the liquid reservoir 7c in the sealed container 7. Injection is performed until L reaches a predetermined liquid level.

after that,! 7a and the valve 11 to seal the container 7 and leave it for a predetermined period of time.

After a predetermined period of time has elapsed, the drain port 8 is connected to a waste liquid tank (not shown), and the valve 9 is opened to discharge the hydrogen fluoride acid in the liquid reservoir 7C. After discharging the hydrogen fluoride acid, the exhaust port 12 is connected to an exhaust duct (not shown), the valve 13 is opened, and the hydrogen fluoride gas in the container 7 is exhausted, and the valve 11 is opened to serve as an air supply port and liquid supply. Air is sent into the container 7 from the port 10 to replace the inside of the container with air. After that, pure water is injected into the container 7 from the air supply port/liquid supply port 10 to clean the inside of the container, and then the valve 9 is closed and the liquid reservoir 7C of the container is filled with pure water.
the law of nature. After that, close the valve 13 and close the lid 7a 1Fll.
Then, the decomposition liquid accumulated in the decomposition liquid receiving tray 5 is collected using a micrometer and a bed, and the decomposition liquid is analyzed using an atomic absorption spectrometer.

On the other hand, when recovering the decomposition liquid, the container 7 is tilted and the pure water in the container is discharged from the mouth of the container in preparation for the next decomposition operation.

[Effects of the Invention] As explained above, the device of the present invention is safe and easy to operate because there is no need for a person to manually put the beaker containing hydrofluoric acid in and out of the closed container. It is safe because people are not exposed to harmful gases when collecting decomposition liquid, and it has various effects such as no danger at all since container cleaning does not require strong acids or by hand. can play.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an embodiment of the disassembly apparatus of the present invention, and FIG. 2 is a sectional view of a conventional disassembly apparatus. DESCRIPTION OF SYMBOLS 1... Airtight container, 1a... Lid, 2... Beaker, 3... Wafer carrier, 4... Support stand, 5
... Decomposition liquid saucer, 6... Carry V cover, 7.
... airtight container, 7a... lid, 7b... platform,
7C...Liquid reservoir, 8...Drain port, 10...Air supply port and liquid supply port, 12...Exhaust port, 9,11.13.
・・Valve, ``...Thin film, W...Single conductor substrate, !・
・・Decomposition liquid, ・・Hydrofluoric acid. Patent applicant: Toshiba Corporation (7 agents, patent attorneys, 1) Eiji Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A semiconductor substrate having a thin film such as an oxide film is stored upright in a closed container, and the thin film is removed by hydrogen fluoride gas generated from a hydrofluoric acid solution in the closed container. A device for decomposing a semiconductor thin film, which decomposes a substance and receives the decomposed liquid in a decomposed liquid receiving tray in the sealed container, characterized in that the sealed container is provided with an air supply port and an exhaust port. Thin film decomposition equipment. 2. The semiconductor thin film decomposition device according to claim 1, wherein the closed container is provided with a liquid supply port that also serves as an air supply port, or a liquid supply port that also serves as an air supply port, and a liquid drain port.