JPH0845859A - Manufacture of semiconductor - Google Patents

Abstract

PURPOSE:To prevent a crack in a film and a haze caused by particles on the wafer face, by inserting the wafer in a reaction furnace at a given speed or below and keeping the temperature of the furnace below a given level while the wafer is put in the reactive furnace. CONSTITUTION:Wafers 8 are mounted horizontally on a multiple-stage boat 9. The boat 9 with the wafers 8 is inserted in the inner reactive furnace 3 at an inserting speed of 20mm/min or below. At this time, the inner temperature of the furnace 3 is adjusted at 600 deg.C or below by a heater 1. A reactive gas is fed through a reactive gas conduction port 6 at a lower end part of the inner reactive tube 3 to form a film on the wafer 8. The waste reactive gas is discharged from an outer reactive tube 2 to a discharge tube 7 through an inlet flange 4. In this way, a crack in the film on the wafer 8 is prevented and particles on the face of the wafer 8 that cause a haze are prevented at the same time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing method, and more particularly to a semiconductor manufacturing method for forming various thin films on a wafer surface by chemical vapor deposition.

[0002]

2. Description of the Related Art As one of semiconductor manufacturing methods, there is a method of forming various thin films on a wafer surface by chemical vapor deposition.

First, referring to FIG. 3, a vertical CVD apparatus for manufacturing a semiconductor by chemical vapor deposition, particularly a vertical furnace which is a main part of the vertical CVD apparatus will be described.

In the vertical CVD apparatus, wafers are horizontally loaded in multiple stages in a vertical reaction tube surrounded by a heater, and SiH ₄ --N ₂ O or TEOS is heated with a heater at a predetermined temperature. Is introduced into the wafer surface to introduce SiO
_It produces a thin film such as ₂ .

An outer reaction tube 2 is provided inside the heater 1, an inlet flange 4 is airtightly provided at a lower end of the outer reaction tube 2, and an inner reaction tube 3 whose lower end is supported by the inlet flange 4 is the outside. It is provided concentrically with the reaction tube 2. A cylindrical space 5 having a closed lower end is formed between the inner reaction tube 3 and the outer reaction tube 2. A reaction gas introduction port 6 is located below the inner reaction tube 3 and communicates with the inlet flange 4, and an exhaust tube 7 is provided.
Are provided so as to communicate with the lower end of the space 5.

A boat 9 for holding wafers 8 in a horizontal posture in multiple stages is provided with a metal furnace lid 11 via a boat cap 10.
The boat 9 is supported by a boat elevator (not shown) via the metal furnace lid 11 so as to be able to move up and down, and is inserted into the inner reaction tube 3. In a state where the boat 9 is completely loaded in the inner reaction tube 3,
The metallic furnace lid 11 is in airtight contact with the inlet flange 4 to hermetically close the inside of the outer reaction tube 2.

When the wafers are processed, the boats 9 are loaded with the wafers 8 in a horizontal posture in multiple stages, and the boats 9 loaded with the wafers are loaded into the internal reaction tubes 3.
With the inside heated to a predetermined temperature by the heater 1,
The reaction gas is introduced from the lower end of the inner reaction tube 3 through the reaction gas introduction port 6, the wafer 8 is processed, and the gas after the reaction is further introduced from the inside of the outer reaction tube 2 through the inlet flange 4 into the exhaust pipe 7 and vacuum. The air is exhausted from a pipe (not shown).

Normally, when forming a SiO ₂ film, SiH ₄ --N ₂
The temperature in the reaction furnace is maintained at 800 ° C for O system and 700 ° C for TEOS pyrolysis, and the charging speed of the boat 9 is 100 mm.
It was treated as / min.

[0009]

In recent years, the density of semiconductor devices has been increasing and the productivity has been further improved, so that the wafer diameter has been increasing. With the increase in diameter of the wafer, the effect of thermal stress when inserting the wafer into the reaction furnace increases, and cracks occur in the film formed on the wafer surface,
The thin film was damaged, causing dust generation. This dust generation causes particles and haze (roughness of the surface of the thin film) after film formation, resulting in deterioration of the quality and yield of semiconductor devices.

In view of the above circumstances, the present invention provides a semiconductor manufacturing method for reducing the generation of particles and haze in the semiconductor manufacturing process.

[0011]

The present invention relates to a semiconductor manufacturing method in which a wafer is loaded into a reaction furnace and various thin films are formed on the surface of the wafer by chemical vapor deposition. The charging rate is 20 mm / min or less, and the temperature inside the reaction furnace at the time of charging is 600 ° C. or less.

[0012]

[Function] The temperature inside the reaction furnace when the wafer is placed inside the reaction furnace is set to 6
To prevent cracks from occurring by setting the temperature below 00 ° C and reducing the amount of heat applied to the wafer per unit time during charging into the reaction furnace, and further reduce the charging speed to below 20 mm / min. Provides sufficient time for the impurities adhering to the wafer surface to be desorbed, prevents contamination of the reaction furnace by the impurities, and prevents particles from adhering to the wafer surface and haze.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As a result of various experiments, the present inventor has confirmed that the amount of particles and haze generated has a great relationship with the temperature in the furnace during charging and the charging speed.

FIG. 1 shows the relationship between the wafer loading rate and the number of particles generated when the wafer loading rate is changed when the furnace temperature is 700 ° C. As shown in FIG. 1, when the wafer loading speed is about 50 mm / min, the number of particles generated sharply decreases with a decrease in the wafer loading speed, and thereafter gradually decreases with a decrease in the wafer loading speed.

Further, FIG. 2 shows a wafer loading speed of 20 mm / min.
The relation between the temperature in the furnace and the number of particles generated is shown when the temperature in the furnace is changed. As shown in FIG. 2, the number of generated particles is remarkably reduced when the temperature in the furnace is from the high temperature side to 600 ° C., and the number of generated particles is hardly changed even when the temperature is lowered from 550 ° C.

From the above relationship, when the amount of heat applied to the wafer per unit time during charging into the reaction furnace is reduced, the generation of cracks is suppressed, and the charging speed is reduced, so that impurities adhering to the wafer surface are removed. Since sufficient time is provided for desorption, it is possible to prevent contamination in the reaction furnace due to impurities, and prevent particles from adhering to the wafer surface and generating haze.

That is, the temperature inside the furnace during charging is lowered to 600 ° C.,
Particles can be generated by reducing the charging speed to 20 mm / min.
The amount of haze generated is significantly reduced. Table 1 shows a specific relationship between the wafer loading rate, the temperature in the reaction furnace, the amount of particles generated, and the amount of haze generated.

[0019]

[Table 1]

As can be seen from Table 1, when the target value of the number of particles is 30, the manufacturing conditions are such that the wafer loading speed is 20 mm / min or less and the reaction furnace temperature is 600 ° C. or less.

Although the present invention is effective for the SiO ₂ film in the CVD manufacturing method, of course, other polysilicon film, nitride film, phosphorus-doped polysilicon film, amorphous silicon film,
It goes without saying that it is also effective for such cases.

[0022]

As described above, according to the present invention, since the generation of particles and haze during film formation is suppressed, the yield in semiconductor device manufacturing is improved, and the generation of film cracks can be suppressed. The cleaning and maintenance cycle of wafers and boats is lengthened, and excellent effects such as improved productivity are exhibited.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the wafer loading rate and the number of particles generated when the wafer loading rate is changed when the furnace temperature is 700 ° C.

FIG. 2 is a diagram showing the relationship between the temperature inside the furnace and the number of particles generated when the temperature inside the furnace is changed at a wafer loading rate of 20 mm / min.

FIG. 3 is an explanatory diagram of a vertical furnace which is a main part of the vertical CVD apparatus.

[Explanation of symbols]

 1 Heater 2 External Reaction Tube 3 Internal Reaction Tube 4 Inlet Flange 5 Space 6 Reaction Gas Introducing Port 7 Exhaust Pipe 8 Wafer 9 Boat 10 Boat Cap 11 Metal Furnace Lid

Claims (1)

[Claims] 1. A method for manufacturing a semiconductor, wherein a wafer is loaded into a reaction furnace and various thin films are formed on the surface of the wafer by chemical vapor deposition, and a loading speed of the wafer into the reaction furnace is 2
A semiconductor manufacturing method characterized in that the temperature in the reaction furnace at the time of charging is 0 mm / min or less and the temperature in the reaction furnace is 600 ° C. or less.