JPS63119521A - Apparatus for vapor phase growth of organic metal - Google Patents

Abstract

PURPOSE:To provide a high-quality, high-reliability IC by providing an adsorbing chamber and allowing partial hydrocarbon liberated from a source gas to be adsorbed by an adsorbing agent, thereby reducing the carbon mixing into the grown film. CONSTITUTION:In the middle of an introducing pipe 12 for making a source gas flow into a reaction chamber, an adsorbing chamber 3 containing an adsorbing agent 31 is provided, and the adsorbing chamber 3 is heated to a temperature lower than the temperature at which the vapor phase cracking of the source gas occurs, providing a construction in which partial hydrocarbon liberated from the source gas is adsorbed by the adsorbing agent 31. For example, in the adsorbing chamber 3 made of a transparent quartz tube, the adsorbing agent 31 of hydrocarbon made of an alumina (Al2O3) powder agent is used. With this, the carbon mixing into the grown metallic film can be reduced appropriately.

Description

[Detailed Description of the Invention] [Summary] An adsorption chamber heated to a low temperature is provided in the middle of the source gas introduction pipe to the reaction chamber, and a part of the liberated hydrocarbons is adsorbed and removed. . By doing so, the metal growth film becomes highly purified.

[Industrial Application Field] The present invention relates to an improvement in a metal organic chemical vapor deposition apparatus (MOCVD apparatus).

Conventionally, in the manufacturing method of semiconductor devices such as ICs, a semiconductor film or other metal film is deposited on a semiconductor substrate.

The vapor phase growth method for growing insulating films is widely used and is one of the basic techniques for semiconductor manufacturing.

Such vapor phase growth methods are divided into two main types: chemical vapor deposition (CVD) and physical growth (PVD). Phase growth method (MOC'VD: MetalOrgan
ic Chemical Vapor Deposit
tion), which uses organic metal gas as a source gas (raw material gas) and thermally decomposes it to grow a film.

However, in this MOCVD method, sufficient care must be taken to prevent impurities contained in the source gas from being mixed into the grown film.

[Prior art] Now, the MOCVD method can be grown at low temperature under normal pressure or reduced pressure, and like other CVD methods, it has good coverage (step coverage). For example, it can deposit an aluminum film with good coverage. can be done.

Traditionally, aluminum films have been used as electrode wiring for ICs, but because no suitable source gas has been developed, CVD methods have not been used, and PVD methods such as sputtering and vapor deposition have been used exclusively. Therefore, there was a drawback of poor coverage.

That is trimethylaluminum (TMAL; Al (
CH)G), triethylaluminum (TEAL
Organo-aluminiums such as ;Al (CH)3 ) and triisobutylaluminum (TIBAL;^1 (CH)3 ) have been developed and can be deposited by MOCVD methods, thus improving coverage and improving IC It has become useful for increasing reliability and quality.

Furthermore, when manufacturing compound semiconductor devices such as GaAs, the MOCVD method can be applied to the epitaxial growth method to easily obtain a heterojunction of compound semiconductor crystal layers, and is a method that is attracting particular attention in this field. .

A conventional schematic sectional view of an MOCVD apparatus for growing by such MOCVD method is shown in FIG. 2, in which 1 is a source container, 11 is a hydrogen gas inlet, 12 is a source gas introduction pipe, and 2 is Reaction chamber
S chamber), 20 is a wafer, 21 is a susceptor that rotates with the wafer placed thereon, 22 is a high-frequency heating coil, 23 is an exhaust port, and the reaction chamber, introduction tube, etc. are all made of transparent quartz material.

For example, when growing an aluminum film using such an MOCVD apparatus, a solution of triisobutylaluminum (TIBAL) is placed in the source container 1, hydrogen gas is introduced into the solution and bubbled, and the hydrogen gas is used as a carrier gas. The T I BAL gas thus obtained is sent to the surface of the wafer 20 in the reaction chamber 2 through the introduction pipe 12 . At that time, the wafer is heated to a temperature of about 250°C. Then, a thermally decomposed aluminum film grows on the wafer surface.

Although FIG. 2 illustrates a vertical reaction chamber, horizontal reaction chambers are also used.

[Problems to be Solved by the Invention] Incidentally, in the growth method using the MOCVD apparatus as described above, since the film is grown by thermally decomposing the combined gas of hydrocarbon and metal, the PVD method is not suitable. It has the disadvantage that hydrocarbons are more likely to be mixed into the coating than in the conventional method. Among hydrocarbons, there is no need to worry about hydrogen because it becomes gaseous and diffuses, but contamination occurs when carbon gets mixed into the film.

When such carbon is included in the grown film, high purity IC can be obtained.
This will have an adverse effect on the board, impairing its quality and reliability.

The present invention proposes an MOCVD apparatus having a structure that reduces the incorporation of carbon into such a grown film.

[Means for solving the problem] The purpose is to provide an adsorption chamber containing an adsorbent in the middle of the introduction pipe through which the source gas flows into the reaction chamber,
An MO configured to heat the adsorption chamber to a temperature lower than the temperature at which the source gas decomposes in the gas phase, so that some of the hydrocarbons liberated from the source gas are adsorbed onto the adsorbent.
Achieved by CVD equipment.

[Function] That is, the MOCVD apparatus according to the present invention has a structure in which an adsorption chamber heated to a low temperature is disposed in the middle of the source gas introduction pipe, and some liberated hydrocarbons are adsorbed and removed by an adsorbent. Make it. By doing so, the amount of carbon mixed into the metal growth film can be reduced accordingly.

[Example] Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 shows a schematic cross-sectional view of the MOCVD apparatus according to the present invention, in which 3 is an adsorption chamber made of a transparent quartz tube, 31 is a hydrocarbon adsorbent made of alumina (+ Al10) powder, and 32 is a heating With a heater, adsorption chamber 3 like this
is provided in the middle of the source gas introduction pipe 12. Note that other members that are the same as those in FIG. 2 are given the same symbols.

In such an MOCVD apparatus, the heating temperature of the reaction chamber 2 is set to T1. If the heating temperature of the adsorption chamber chamber 3 is set to T2 and T,>7'2, then in the adsorption chamber 3 at the heating temperature T2, a decomposition reaction of MR→MR, +R2 occurs, and in the next reaction chamber 2 at the heating temperature T2. So, MR, → M+R.

A decomposition reaction occurs. Here, M is a metal and all R are hydrocarbons. Through this reaction, the metal M does not disappear and becomes a grown film, but the hydrocarbons are absorbed into the adsorbent 31 before the amount of R2 enters the reaction chamber 2. The amount of carbon mixed into the metal film during the decomposition reaction in the reaction chamber 2 is reduced accordingly.

Now, to explain with an example of an aluminum film, the heating temperature (T2) of the adsorption chamber 3 was set to 150°C, the heating temperature (T1) of the reaction chamber 2 was set to 250°C, and triisobutyl aluminum was prepared using hydrogen gas as a carrier gas. (TIB
AL) flows into the reaction chamber 2 through the adsorption chamber 3. Then, in adsorption chamber 3, A (C4+-1,)3;
Hz input C=cH.

(TIBAL) (DIBAL-H')
A decomposition reaction of (iso7° Reiren) occurs, and a decomposition reaction of (CH,) occurs in reaction chamber 2.
Hydrocarbons such as uc-CH2 are removed before entering the reaction chamber 2, and contamination with the metal film is reduced by that amount.

Although the above has been explained using an example of an aluminum film, it goes without saying that the apparatus according to the present invention can also be applied to the growth of a compound semiconductor film using triethyl gallium or the like as a source gas.

[Effect of the invention] As is clear from the above explanation, the MOC according to the present invention
The VD apparatus has the advantage that the incorporation of carbon into the grown film is reduced, resulting in higher quality and higher reliability of the IC.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the MOCVD apparatus according to the present invention, and FIG.
The figure is a cross-sectional view of a conventional MOCVD apparatus. In the figure, 1 is a source container, 11 is a hydrogen gas inlet, 12 is a source gas introduction pipe, 2 is a reaction chamber, 20 is a wafer, 21 is a susceptor, 22 is a high frequency heating coil,
23 is an exhaust port, 3 is an adsorption chamber, 31 is alumina (adsorbent)
Figure 0 bolt 0CVD guy 1 Figure 2

Claims (1)

[Claims] An adsorption chamber containing an adsorbent is provided in the middle of the introduction pipe through which the source gas flows into the reaction chamber, and the adsorption chamber is heated to a temperature lower than the temperature at which the source gas decomposes in the gas phase to release it from the source gas. 1. An organometallic vapor phase epitaxy apparatus, characterized in that the organometallic vapor phase growth apparatus is configured such that a part of the hydrocarbons produced by the hydrocarbons is adsorbed by the adsorbent.