JP2644819B2 - heating furnace - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heating furnace used in a semiconductor device manufacturing process.

2. Description of the Related Art A conventional heating furnace used for manufacturing a semiconductor device is an electric heating furnace in which a heater is wound around a quartz tube into which a semiconductor wafer is put and covered with a heat insulating material. The heater was heated by supplying electricity at a commercial frequency of 50 Hz or 60 Hz.

Problems to be Solved by the Invention In a conventional electric heating furnace used for manufacturing a semiconductor device,
The semiconductor wafer placed in the heating furnace is gradually heated from room temperature to a temperature around 900 ° C, but heat is applied from the outer peripheral portion of the semiconductor wafer, so that the heat is applied between the inner peripheral portion and the outer peripheral portion of the semiconductor wafer. A temperature difference occurs. As a result, the semiconductor wafer is deformed, causing crystal defects, and causing various problems in miniaturization and high integration of the semiconductor device. There is also a method of reducing the rate of temperature change when the temperature of the electric heating furnace is raised in order to make the temperature distribution in the plane of the semiconductor wafer uniform, but in this case, the heat treatment time increases and the production efficiency decreases accordingly. There was a limit.

An object of the present invention is to provide a heating furnace that uniformly and efficiently heats the entire semiconductor wafer in a short time.

Means for Solving the Problems The heating furnace of the present invention is a high-frequency induction heating furnace that heats the entire semiconductor wafer uniformly at a predetermined frequency at a pre-stage relative to the semiconductor wafer input port, and directly by high frequency in a short time. An electric heating furnace for performing a heat treatment such as deposition, diffusion, or annealing of impurities is provided at a later stage.

According to the heating furnace of the present invention, when a semiconductor wafer is charged, first, the whole semiconductor wafer is heated uniformly and efficiently to a processing temperature of a subsequent electric heating furnace by a high frequency in a short time when the semiconductor wafer is charged. After that, since the semiconductor wafer is put into an electric heating furnace, deformation of the semiconductor wafer caused by uneven temperature distribution in the semiconductor wafer surface which occurs when the temperature of the semiconductor wafer rises is reduced, and generation of crystal defects is suppressed. be able to.

Embodiment An embodiment of a heating furnace according to the present invention will be described with reference to the side view shown in FIG.

In this heating furnace, the first stage is a high-frequency induction heating furnace 1 and the second stage is an electric heating furnace 2. One quartz tube 3 is arranged at the center of the high-frequency induction heating furnace 1 and the electric heating furnace 2. A high-frequency coil 4 is wound around the quartz tube 3 in the region of the high-frequency induction heating furnace 1, both ends of the high-frequency coil 4 are connected to a high-frequency power supply 5, and a heater 6 is provided in the quartz tube 3 in the region of the electric heating furnace 2.
Is wound, and both ends of the heater 6 are connected to a commercial frequency power supply 7 of 50 Hz or 60 Hz. A gas introduction pipe 10 for introducing a gas is provided on the opposite side of the semiconductor wafer input port 9, and the periphery of the quartz tube 3 is insulated. The structure is covered with the material 11.

Next, a method of using the heating furnace of the present invention will be described.
The quartz board 12 on which the semiconductor wafer 8 is mounted is inserted through the semiconductor wafer input port 9, and the semiconductor wafer is shortened to the temperature of the electric heating furnace 2 while the semiconductor wafer 8 passes through the high-frequency induction heating furnace 1. The heating is performed by high frequency in a timely and uniformly linear manner. After that, the semiconductor wafer 8 is placed in the electric heating furnace 2, where impurities are deposited, diffused or annealed.

Next, the high-frequency induction heating furnace will be described in more detail.

In the high-frequency induction heating furnace 1, when the penetration depth of the high-frequency current into the semiconductor wafer is δ (cm), the following relational expression holds.

Here, ρ (Ωcm) is the specific resistance of the semiconductor wafer, μ
Is the relative magnetic permeability, and f (Hz) is the frequency. By changing the frequency f, the penetration depth δ of the high-frequency current can be changed. Assuming that the diameter of the semiconductor wafer is d (cm), the heating furnace 1 supplies a high-frequency current to the wafer and obtains a sufficient heating efficiency. From the viewpoint of obtaining a sufficient heating efficiency, a frequency of f ≧ 4 × 10 ³ · ρ / (μ · d ² ) To be able to occur.

As compared above, the semiconductor wafer is directly heated to the processing temperature of the electric heating furnace in a high-frequency induction heating furnace uniformly and in a short time by the high frequency, so that the semiconductor wafer is not in the surface of the semiconductor wafer as in the conventional method. Since there is no uniform temperature distribution,
Deformation of the semiconductor wafer does not occur, and generation of crystal defects can be suppressed.

According to the heating furnace of the present invention, in a semiconductor wafer heat treatment step in a semiconductor device manufacturing process, when a semiconductor wafer is put into an electric heating furnace, a high-frequency induction heating provided before the electric heating furnace is provided. By directly heating the temperature of the semiconductor wafer uniformly and efficiently to the processing temperature in a short time by a high frequency in a furnace, the deformation of the semiconductor wafer can be reduced, the generation of crystal defects can be suppressed, and the processing time can be shortened. As a result, miniaturization and high integration of the semiconductor integrated circuit become possible, and the yield can be improved.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the heating furnace of the present invention. 1 ... high frequency induction heating furnace, 2 ... electric heating furnace, 3 ...
... Quartz tube, 4 ... High frequency coil, 5 ... High frequency power supply, 6
... heater, 7 ... commercial frequency power supply, 8 ... semiconductor wafer, 9 ... semiconductor wafer inlet, 10 ... gas inlet tube, 11
…… Insulation material, 12 …… Quartz boat.

Claims (1)

(57) [Claims] 1. A heating furnace provided with a high-frequency induction heating furnace for directly heating a semiconductor wafer by high frequency at a preceding stage with respect to a semiconductor wafer input port and an electric heating furnace for performing a heat treatment at a later stage. Let the specific resistance of the wafer be ρ (Ωc
m), when the relative magnetic permeability of the semiconductor wafer is μ and the diameter of the semiconductor wafer is d (cm), the frequency f (Hz) of the high frequency is f ≧ 4 × 10 ³ · ρ / (μ · d ² ) A heating furnace characterized by the following.