JP2007134483A

JP2007134483A - Vertical diffusion furnace

Info

Publication number: JP2007134483A
Application number: JP2005325850A
Authority: JP
Inventors: Isao Yokoyama; 勲横山
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2005-11-10
Filing date: 2005-11-10
Publication date: 2007-05-31

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical diffusion furnace which makes uniform a flow of a process gas in a heat treatment chamber. <P>SOLUTION: An interior of a reaction tube 1 is partitioned by a baffle plate 2, a part below the baffle plate 2 is assigned as a heat treatment chamber 11, and a part above the baffle plate 2 is assigned as a gas introduction chamber 12. An exhaust port 3 is formed at one location at a lower end of the reaction tube 1. A hole of the baffle plate 2 is provided so that a portion of the gas exhaust port 3 has a smaller opening rate than a portion on the opposite side in a plane. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は縦型拡散炉に関する。 The present invention relates to a vertical diffusion furnace.

従来より、ウエハに不純物を拡散したり、熱酸化膜を形成したりする際に、複数のウエハを同時に熱処理できる拡散炉が使用されている。拡散炉には、反応管やヒータを横に配置した横型拡散炉と、反応管やヒータを縦に配置した縦型拡散炉がある。
下記の特許文献１には、上端が閉鎖され、下端が開口した単一のチューブ（石英製の反応管）で熱処理炉を構成し、このチューブの上方をバッフル板（微細な孔を開けた板）で仕切り、このバッフル板から下方を熱処理室とした縦型拡散炉が記載されている。この熱処理室内に、多数の基板を上下方向で並列に、水平に保持したボートが配置される。 Conventionally, a diffusion furnace capable of simultaneously heat-treating a plurality of wafers when impurities are diffused into a wafer or a thermal oxide film is formed has been used. As diffusion furnaces, there are a horizontal diffusion furnace in which reaction tubes and heaters are arranged horizontally, and a vertical diffusion furnace in which reaction tubes and heaters are arranged vertically.
In Patent Document 1 below, a heat treatment furnace is constituted by a single tube (quartz reaction tube) having an upper end closed and a lower end opened, and a baffle plate (a plate having fine holes) is formed above the tube. ), And a vertical diffusion furnace having a heat treatment chamber below the baffle plate is described. In this heat treatment chamber, a boat holding a large number of substrates in parallel in the vertical direction is disposed.

この縦型拡散炉では、プロセスガスを導入するガス導入管の先端部を、前記バッフル板とチューブの天井面との間に配置し、この先端部に上向きの噴射口を設けている。これにより、ガス導入管に供給されたプロセスガスが、噴射口からチューブの上端面に向けて噴射された後に、バッフル板の孔から下方に向かい、熱処理室内に導入される。
なお、特許文献１には、プロセスガスの排気口についての記載がないが、通常の縦型拡散炉は、チューブの下端に排気口が設けられている。
特開平８−１０７０８２号公報 In this vertical diffusion furnace, the distal end portion of the gas introduction pipe for introducing the process gas is disposed between the baffle plate and the ceiling surface of the tube, and an upward injection port is provided at the distal end portion. Thereby, after the process gas supplied to the gas introduction pipe is injected from the injection port toward the upper end surface of the tube, it is introduced downward into the heat treatment chamber from the hole of the baffle plate.
Although Patent Document 1 does not describe a process gas exhaust port, an ordinary vertical diffusion furnace is provided with an exhaust port at the lower end of a tube.
JP-A-8-107082

特許文献１には、チューブ内にバッフル板を設けることで、プロセスガスを均一に熱処理室に流し込むことができると記載されている。しかしながら、実際には、チューブの断面内で、排気口側の部分と反対側の部分とでプロセスガスの流量に差が生じ、熱処理室内のプロセスガスの流れが不均一になるという問題点がある。
本発明は、熱処理室内のプロセスガスの流れを均一にすることができる縦型拡散炉を提供することを課題とする。 Patent Document 1 describes that by providing a baffle plate in the tube, the process gas can be uniformly poured into the heat treatment chamber. However, in practice, there is a problem in that the flow rate of the process gas differs between the portion on the exhaust port side and the portion on the opposite side in the cross section of the tube, and the flow of the process gas in the heat treatment chamber becomes non-uniform. .
An object of the present invention is to provide a vertical diffusion furnace that can make the flow of a process gas uniform in a heat treatment chamber.

上記課題を解決するために、本発明は、反応管内をバッフル板で仕切り、このバッフル板から下を熱処理室とし、バッフル板から上をガス導入室とした縦型拡散炉であって、前記反応管の下端に排気口が形成され、前記バッフル板の孔は、面内で、排気口側の部分が反対側の部分よりも開口率が小さくなるように設けてあることを特徴とする縦型拡散炉を提供する。 In order to solve the above problems, the present invention provides a vertical diffusion furnace in which a reaction tube is partitioned by a baffle plate, a heat treatment chamber is provided below the baffle plate, and a gas introduction chamber is provided above the baffle plate. A vertical type characterized in that an exhaust port is formed at the lower end of the pipe, and the hole of the baffle plate is provided in such a manner that the portion on the exhaust port side is smaller in opening than the portion on the opposite side in the plane. Provide a diffusion furnace.

バッフル板の孔を、面内で、排気口側の部分が反対側の部分よりも開口率が小さくなるように設けるためには、例えば、全て同じ直径で、排気口側の部分が反対側の部分よりも低い密度で配置するか、排気口側の部分で反対側の部分よりも直径を小さくして、全て同じ密度で配置する。
本発明の縦型拡散炉によれば、バッフル板の孔が、面内で、排気口側の部分が反対側の部分よりも開口率が小さくなるように設けてあるため、開口率が面内で同じであるバッフル板を使用した縦型熱拡散炉よりも、熱処理室内のプロセスガスの流れを均一にすることができる。 In order to provide the holes of the baffle plate so that the opening ratio of the exhaust side portion is smaller than that of the opposite side portion in the plane, for example, all of the diameters are the same and the exhaust side portion is on the opposite side. Arrange them at a lower density than the part, or make the diameter smaller at the part on the exhaust port side than the part on the opposite side, and arrange them at the same density.
According to the vertical diffusion furnace of the present invention, since the hole of the baffle plate is provided in the plane so that the opening ratio is smaller on the exhaust side than on the opposite side, the opening ratio is in-plane. The process gas flow in the heat treatment chamber can be made more uniform than in the vertical thermal diffusion furnace using the same baffle plate.

以下、本発明の実施形態について説明する。
図１は、本発明の一実施形態に相当する縦型熱拡散炉を示す概略構成図である。図２および３は、バッフル板の平面図である。
この実施形態の縦型拡散炉は、反応管１内をバッフル板２で仕切り、このバッフル板２から下を熱処理室１１とし、バッフル板２から上をガス導入室１２としている。また、反応管１の下端の一カ所に排気口３が形成されている。 Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a schematic configuration diagram showing a vertical thermal diffusion furnace corresponding to an embodiment of the present invention. 2 and 3 are plan views of the baffle plate.
In the vertical diffusion furnace of this embodiment, the inside of the reaction tube 1 is partitioned by a baffle plate 2, the heat treatment chamber 11 is below the baffle plate 2, and the gas introduction chamber 12 is above the baffle plate 2. Further, an exhaust port 3 is formed at one position on the lower end of the reaction tube 1.

ガス導入管は、導入口４１と縦管４２と横管４３からなり、導入口４１が、反応管１の下端外側の、ガス排出口３の反対側に配置されている。縦管４２は、反応管１の外側に配置されている。横管４３は、反応管１の周面を貫通して、ガス導入室（バッフル板２と反応管１の天井面との間）１２内に配置されている。横管４３はバッフル板２の中心まで延び、その先端部に上向きの噴射口が設けてある。このガス導入管により、ガス導入室１２内にプロセスガスが導入され、バッフル板２の中心から上向きにプロセスガスが噴射されるようになっている。 The gas introduction pipe includes an introduction port 41, a vertical tube 42, and a horizontal tube 43, and the introduction port 41 is disposed on the opposite side of the gas discharge port 3 outside the lower end of the reaction tube 1. The vertical tube 42 is disposed outside the reaction tube 1. The horizontal tube 43 penetrates the peripheral surface of the reaction tube 1 and is disposed in the gas introduction chamber 12 (between the baffle plate 2 and the ceiling surface of the reaction tube 1). The horizontal tube 43 extends to the center of the baffle plate 2 and is provided with an upward injection port at its tip. The process gas is introduced into the gas introduction chamber 12 by the gas introduction pipe, and the process gas is jetted upward from the center of the baffle plate 2.

バッフル板２は石英製の板に多数の孔２１が形成されたものであり、この実施形態では、図２に示すように、全て同じ直径の孔２１が、排気口３側の部分が反対側の部分よりも低い密度で配置されている。これにより、バッフル板２の面内で、排気口側の部分が反対側の部分よりも開口率が小さくなっている。
この縦型拡散炉の熱処理室１１内に、多数のウエハＷが水平に保持されたボート５を入れて密封する。この例では、シールキャップ６上に固定された保温筒７の上に、ウエハＷが保持されたボート５を配置した状態で、これらを一緒に上昇させてボート５と保温筒７を反応管１内に入れ、シールキャップ６を反応管１に密着させる。 The baffle plate 2 is a quartz plate in which a large number of holes 21 are formed. In this embodiment, as shown in FIG. 2, all the holes 21 having the same diameter are provided on the opposite side on the exhaust port 3 side. It is arranged at a lower density than the part. Thereby, in the surface of the baffle plate 2, the opening ratio is smaller in the exhaust side portion than in the opposite side portion.
In the heat treatment chamber 11 of this vertical diffusion furnace, a boat 5 in which a number of wafers W are held horizontally is placed and sealed. In this example, in a state where the boat 5 holding the wafer W is arranged on the heat insulating cylinder 7 fixed on the seal cap 6, these are raised together to connect the boat 5 and the heat insulating cylinder 7 to the reaction tube 1. The seal cap 6 is brought into close contact with the reaction tube 1.

そして、ガス導入管の導入口４１から供給されたプロセスガスは、縦管４２を上昇して横管４３からガス導入室１２に入り、横管４３先端部の噴射口から反応管１の天井面に向けて噴射された後に、バッフル板２の孔から下方に向かい、熱処理室１１内に導入される。ここで、排気口３側の部分と反対側の部分とにおける、バッフル板２の孔２１の開口率の差に応じて、バッフル板２の直下でプロセスガスの流量に差が生じる。その結果、熱処理室１１でプロセスガスが排気口３側に向かう量と、反対側に向かう量が同じくらいになり、熱処理室１１内のプロセスガスの流れが均一になる。 Then, the process gas supplied from the inlet 41 of the gas inlet pipe rises up the vertical pipe 42 and enters the gas introduction chamber 12 through the horizontal pipe 43, and the ceiling surface of the reaction pipe 1 from the injection port at the tip of the horizontal pipe 43. After being injected toward the bottom, it is directed downward from the hole of the baffle plate 2 and introduced into the heat treatment chamber 11. Here, there is a difference in the flow rate of the process gas directly under the baffle plate 2 according to the difference in the opening ratio of the holes 21 of the baffle plate 2 between the portion on the exhaust port 3 side and the portion on the opposite side. As a result, the amount of process gas directed toward the exhaust port 3 and the amount directed toward the opposite side in the heat treatment chamber 11 are approximately the same, and the flow of process gas in the heat treatment chamber 11 becomes uniform.

これに対して、バッフル板２の孔が面内で均一な開口率となるように形成されている場合は、図４に示すように、バッフル板２の直下でプロセスガスの流量は均一である。この場合、熱処理室１１でプロセスガスが排気口３側に向かう量が多くなり、熱処理室１１内のプロセスガスの流れが不均一になる。
図２のバッフル板２に代えて、図３に示すように、孔２１の直径が、排気口３側の部分で反対側の部分より小さく、面内で全て同じ密度で孔２１が配置されたバッフル板を用いてもよい。なお、製造コストの観点からは、同じ直径の孔２１を設ける図２のバッフル板の方が、製造コストが低くできるため好ましい。 On the other hand, when the holes of the baffle plate 2 are formed so as to have a uniform aperture ratio in the plane, the flow rate of the process gas is uniform just below the baffle plate 2 as shown in FIG. . In this case, the amount of process gas directed toward the exhaust port 3 in the heat treatment chamber 11 increases, and the flow of the process gas in the heat treatment chamber 11 becomes uneven.
In place of the baffle plate 2 of FIG. 2, the diameter of the hole 21 is smaller at the portion on the exhaust port 3 side than at the opposite side, and the holes 21 are arranged at the same density in the plane as shown in FIG. A baffle plate may be used. From the viewpoint of manufacturing cost, the baffle plate of FIG. 2 provided with the holes 21 having the same diameter is preferable because the manufacturing cost can be reduced.

本発明の縦型拡散炉の一実施形態を示す概略構成図。The schematic block diagram which shows one Embodiment of the vertical type | mold diffusion furnace of this invention. 実施形態のバッフル板の平面図。The top view of the baffle board of embodiment. 実施形態のバッフル板の平面図。The top view of the baffle board of embodiment. 比較例の縦型拡散炉を示す概略構成図。The schematic block diagram which shows the vertical diffusion furnace of a comparative example.

Explanation of symbols

１…反応管、１１…熱処理室、１２…ガス導入室、２…バッフル板、２１…孔、３…排気口、４１…ガス導入管の導入口、４２…ガス導入管の縦管、４３…ガス導入管の横管、５…ボート、6 …シールキャップ、７…保温筒、Ｗ…ウエハ。 DESCRIPTION OF SYMBOLS 1 ... Reaction tube, 11 ... Heat treatment chamber, 12 ... Gas introduction chamber, 2 ... Baffle plate, 21 ... Hole, 3 ... Exhaust port, 41 ... Inlet port of gas introduction tube, 42 ... Vertical tube of gas introduction tube, 43 ... Horizontal pipe of gas introduction pipe, 5 ... boat, 6 ... seal cap, 7 ... insulation cylinder, W ... wafer.

Claims

A vertical diffusion furnace in which the inside of the reaction tube is partitioned by a baffle plate, the heat treatment chamber is below the baffle plate, and the gas introduction chamber is above the baffle plate,
An exhaust port is formed at the lower end of the reaction tube,
The vertical diffusion furnace according to claim 1, wherein the holes of the baffle plate are provided in such a manner that a portion on the exhaust port side has a smaller opening ratio than a portion on the opposite side.

2. The vertical diffusion furnace according to claim 1, wherein the holes of the baffle plate have the same diameter, and the exhaust side portion is disposed at a lower density than the opposite side portion.

2. The vertical diffusion furnace according to claim 1, wherein the holes of the baffle plate are arranged at the same density with a diameter smaller at the exhaust port side than at the opposite side portion.