JPS63100734A - Heat treatment device - Google Patents

Abstract

PURPOSE:To heat treat wafers evenly assuring excellent quality by a method wherein a processing tube, a heater outside the tube movable in the tube axial direction, an inlet closing door of tube are provided to offset any difference in thermal histories of wafers in case of batch processing. CONSTITUTION:A door 9 is opened feeding a tube 1 with N2 gas to insertion-fix a carrier part 16 loaded with wafers to the tube 1. Then, the door 9 is closed stopping the N2 gas feed to open a valve 5 vacuumizing inside the tube 1 and after closing the valve 5 by turning a switch 7 to feed N2 gas again up to atmospheric pressure. A heater 13 is driven to the position of wafers W and a heat shielding cylinder 12 is retracted to feed processing gas. When the tube 1 is filled with N2 gas, the heater 13 is actuated to start annealing process. After finishing the processing, the heater 13 is stopped to drive the heat shielding cylinder 12 after the temperature is cooled down for retracting the heater 13. At this time, the N2 gas is completely substituted for the processing gas. Through these procedures, the wafers are not subjected to any thermal shock even after withdrawal from the tube 1 to be withdrawn from the tube 1 after satisfactorily cooled down by N2 gas. In such a constitution, the wafers W can be heat-treated evenly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat treatment apparatus for semiconductor wafers, and particularly to a heat treatment apparatus suitable for annealing treatment after metal film formation.

[Conventional technology]

Generally, in the manufacturing process of semiconductor devices, a process of heat-treating a semiconductor wafer under a required atmosphere is essential. For this reason, various heat treatment equipment has been proposed in the past, but the usual equipment is to place the wafer in a purge box attached to an insertion/extraction mechanism, and to purge the air inside the box with an inert gas such as nitrogen. A method is adopted in which the material is inserted into a process tube while being heated and heat treated.

Incidentally, the lamp annealing device can be used, for example, for "electronic materials" No. 2.
5, No. 3 (1986), pages 119 to 122.

[Problem that the invention seeks to solve]

In the above conventional technology, the thermal history between wafers becomes uneven during batch processing, insufficient consideration is given to reducing residual oxygen in the processing chamber, and the heat treatment effect is uneven among wafers within a batch. This leads to deterioration in quality and yield, and also causes problems such as element deterioration due to the formation of natural oxide films on wafers and a reduction in the number of wafers processed in a batch.

In other words, the above-mentioned conventional equipment usually employs batch processing and is already in a high temperature state at the time of insertion, so the first and last wafers tend to receive different thermal histories at the time of insertion, and each wafer This results in differences in the heat treatment effects, resulting in nonuniform characteristics of semiconductor devices and a decrease in yield.

In addition, external oxygen is likely to be drawn in when inserting or withdrawing a wafer, and the formation of a natural oxide film is unavoidable.

The purpose of the present invention is to eliminate the difference in thermal history experienced by each wafer even in a batch processing type heat treatment apparatus, and to further reduce the influence of air entrainment during wafer insertion to obtain a uniform and high-quality heat treatment effect. The purpose of the present invention is to provide a heat treatment device that can perform the following steps.

[Means for solving problems]

The heat treatment apparatus of the present invention includes a process tube into which a member to be heat treated can be inserted, a heater disposed outside the process tube and movable relative to the axis of the process tube, and an opening of the process tube in a sealed state. It is equipped with an opening/closing door that can be closed.

Further, it is preferable that a heat shield cylinder is disposed between the process tube and the heater, and that the heat shield cylinder is provided so as to be relatively movable in the axial direction of the process tube.

Further, the process tube is configured to have a vacuum state inside and to allow required gas to flow therethrough.

[Effect]

In this heat treatment apparatus, when a wafer is inserted, a heat shield cylinder covers the entire tube, and heat supply into the tube is suppressed as much as possible. After inserting the wafer, the tube opening is sealed to prevent air from being entrained. Then, when the heater moves to the wafer position and the heat shield cylinder retreats, heating starts. After the heat treatment, heating of the heater is stopped, and after the temperature is lowered to a required temperature, the heat shield cylinder is moved to the wafer position, and the heater is moved back. Thereafter, the wafer is cooled to a temperature at which it is not affected by external oxygen during extraction, and then the wafer is extracted.

(Example〕 Hereinafter, one embodiment of the present invention will be described based on the drawings.

In the figure, a process tube 1 has a gas passage 1 at its rear end.
a, to which are connected a gas supply pipe 3 connected to the processing gas supply section 2, and an evacuation pipe 6 connected to a vacuum pump 4 and pulp 5, respectively.

Further, a vacuum switch 7 is disposed in the gas passage 1a,
Opening and closing operations are performed at the required vacuum pressure within the tube 1.

Note that the gas passage 1a is covered with a heat insulating material 8.

On the other hand, an opening/closing i@9 having a water-cooled O-ring 10 is disposed at the front end opening of the process tube 1, so that the front end opening can be closed in a sealed state. Further, a normal pressure (atmospheric pressure) detection switch 11 is disposed on the opening/closing door 9 and is activated when the inside of the chain 1 reaches normal pressure.

Furthermore, a heat shield cylinder 12 made of SiC or the like is disposed outside the process tube 1 so as to surround it, and a cylindrical heater 13 is further disposed outside the process tube 1. A heat shielding cylinder driving section 14 and a heater driving section 15 are connected to the heat shielding cylinder 12 and the heater 13, respectively.
The heater 13 and the heater 13 are configured to be able to move independently in the front-rear direction along the tube 1.

In the figure, reference numeral 16 denotes a wafer transport section, which can move in the front and rear directions with respect to the tube 1 to take the wafer W into and out of the tube 1.

According to this configuration, heat treatment can be performed as follows.

That is, when the wafer is inserted, the heater 13 is in a position retracted to the left and is not heated. In this state, the opening/closing door 9 is opened and an inert gas such as nitrogen is flowing from the gas supply section 2 into the tube 1. Then, the wafer W mounted on the wafer transport section 16 is inserted and mounted into the process tube 1.

Next, the opening/closing door 9 is closed, the gas supply is stopped, and the pulp 5 in the exhaust section is opened and the vacuum pump 4 is operated to open the tube 1.
Exhaust the gas inside. Then, when a preset degree of vacuum is reached, the vacuum switch 7 is activated, the pulp 5 is closed, and inert gas is again flowed from the gas supply section 2 until the inside of the tube 1 reaches atmospheric pressure.

Next, after confirming that the inside of the tube 1 has returned to atmospheric pressure with the normal pressure detection switch 11, the heater 13
5, the heat shield cylinder 12 moves to the position of the wafer W, and in contrast to this, the heat shield cylinder 12 retreats to the left.

At the same time, processing gas is flowed from the gas supply section 2, and when the tube 1 is filled, the heater 13 starts energizing heating.
The wafer W is annealed.

After heat annealing is performed for a predetermined period of time, the heater 13 is turned off. Then, after the temperature has decreased to a temperature that does not cause thermal strain to the wafer, the heat shielding cylinder 12 is moved to the right by the drive unit 14, and at the same time, the heater 13 is moved backward. At this point, the gas has been switched from processing gas to inert gas.

Finally, after the wafer W is cooled using an inert gas to the extent that it will not receive a thermal shock even if it is pulled out from the tube 1 and will not react with oxygen in the atmosphere, the opening/closing door 9 is opened and the wafer transport section is opened. 16 to pull out the wafer W from inside the tube 1.

Therefore, according to this embodiment, when inserted into the tube 1,
Differences in thermal history between a plurality of wafers W that are mounted and subjected to annealing processing can be reduced, and uniform processing can be performed on all wafers. In addition, the opening/closing door 9 that seals the front end opening of the tube 1 can suppress air entrainment into the tube 1, making it possible to perform wafer heat processing in batches while reducing the influence of this entrained air.

〔Effect of the invention〕

According to the present invention, there is provided a heater that is disposed on the outside of the process tube into which a member to be heat treated can be inserted and that is movable relative to the tube axis of the process tube, and an opening/closable door that is capable of sealingly closing the opening of the process tube. Therefore, the difference in thermal history between wafers processed simultaneously can be reduced, and the difference in the amount of deformation between the members to be heat processed can be reduced.

In addition, since it is possible to prevent external oxygen from being drawn into the tube, the formation of a natural oxide film on the surface of the heat-treated member is suppressed.
Variations in film quality within a batch can be reduced. Further, by disposing a heat shielding tube between the process tube and the heater and making the heat shielding tube movable relative to the axial direction of the process tube, the heat treatment described above can be performed even better. can.

[Brief explanation of the drawing]

The figure is a sectional view showing the overall configuration of an embodiment of the present invention. 1... Process tube, 2... Gas supply source, 3.
...Gas supply pipe, 4...Vacuum pump, 5...Valve, 6...Evacuum tube, 7...Vacuum switch, 8...
・Insulation material, 9...opening/closing door, 10...0 ring, 11
. . . Normal pressure switch, 12 . . . Heater, 13 . . . Heat shield tube, 14 .

Claims (1)

[Claims] 1. A process tube into which a member to be heat treated can be inserted, a heater disposed outside the process tube and movable relative to the axis of the process tube, and an opening of the process tube sealed. A heat treatment device characterized by comprising an opening/closing door that can be closed in any state. 2. The heat treatment apparatus according to claim 1, wherein a heat shield cylinder is provided between the process tube and the heater so as to be movable in the axial direction of the process tube.