JP2833329B2 - Method for interstitial oxygen precipitation in semiconductor silicon wafer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for interstitial oxygen precipitation in a semiconductor silicon wafer, and more particularly to a semiconductor manufacturing process.

[0002]

2. Description of the Related Art A conventional method of interstitial oxygen precipitation in a semiconductor silicon wafer is to carry out thermal diffusion at 650 ° C. by placing about 100 to 200 semiconductor silicon wafers on a high-purity quartz boat as a pre-heat treatment in a semiconductor manufacturing process. After entering the furnace at a boat speed of 20 to 50 cm / min, the semiconductor silicon wafer is treated in a thermal diffusion furnace for a certain period of time in a nitrogen gas atmosphere, and then is heated for 20 to 5 cm.
The furnace was discharged at a boat speed of 0 cm / min. When the semiconductor silicon wafer enters the heat diffusion furnace, the inside of the heat diffusion furnace is sufficiently replaced with nitrogen gas.

[0003]

The above-mentioned conventional method for interstitial oxygen precipitation in a semiconductor silicon wafer has the following problems.
65-200 semiconductor silicon wafers
As shown in FIG. 4, the heat history at 650 ° C. received by the semiconductor silicon wafer 1 at the temperature of 650 ° C. depends on the position of the semiconductor silicon wafer 1 on the high-purity quartz boat 2 because the semiconductor silicon wafer 1 enters the heat diffusion furnace at 0 ° C. Silicon wafers A and B
Is different. In other words, the latent defect density existing inside the semiconductor wafer is different from that of the semiconductor silicon wafers A and B.
The density of oxygen precipitation defects inside a semiconductor silicon wafer when an N-MOS type DRAM (a random write / read memory that requires a memory holding operation) is formed as shown in FIG. As the position of the semiconductor silicon wafer 1 placed on the substrate becomes closer to the semiconductor silicon wafer A closer to the heat diffusion furnace side, that is, the longer the heat history at 650 ° C., the higher is the oxygen precipitation of about 4 × 10 ⁷ cells / cm ^2. There is a defect density difference. Leakage defect index as shown in FIG. 5 due to protrusion of oxygen precipitation defects into the semiconductor active region when the oxygen precipitation density inside the semiconductor silicon wafer becomes high, or due to insufficient gettering effect of contaminant impurities when the density is low. Increases to N
-There is a problem that instability is caused in the yield of the MOS DRAM.

[0004]

According to the present invention, there is provided a method for precipitating interstitial oxygen in a semiconductor silicon wafer at a temperature of 650 ° C. using a thermal diffusion furnace. A plurality of semiconductor silicon wafers placed on a quartz boat 2 are 450 ± 10
C., the furnace body temperature of the heat diffusion furnace is raised to 650.degree. C., and after a certain time treatment, the furnace body temperature of the heat diffusion furnace is lowered to 450. +-. 10.degree. A plurality of semiconductor silicon wafers 1 placed on a high-purity quartz boat were put out of a thermal diffusion furnace and put on the high-purity quartz boat.
It is characterized in that a difference in thermal history at 650 ° C. caused by positions of a plurality of semiconductor silicon wafers is eliminated.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of the method for interstitial oxygen precipitation in a semiconductor silicon wafer according to the present invention.
It is used as a pre-process for forming an S-type DRAM. The semiconductor silicon wafer 1 placed on the high-purity quartz boat 2 is introduced into the heat diffusion furnace 3 at a furnace temperature of 450 ± 10 ° C. at a boat speed of 50 cm / min by replacing the inside of the heat diffusion furnace with nitrogen gas. Is completed, the furnace body temperature of the heat diffusion furnace 3 is raised to 650 ° C. at a rate of 0.5 ° C./min by increasing the output of the heater 4. After maintaining the furnace body temperature of the thermal diffusion furnace 3 at 650 ° C., the processing is performed for a certain period of time while flowing a nitrogen gas at a predetermined flow rate. Thereafter, the temperature of the furnace body of the heat diffusion furnace 3 is lowered to 450 ± 10 ° C. at a rate of 0.5 ° C./min by lowering the output of the heater 4, and the semiconductor is placed on the high-purity quartz boat 2 from the heat diffusion furnace 3. Silico wafer 1 at boat speed 50cm / min
Let the furnace out.

An N-MOS type DRAM which is not subjected to a high-temperature heat treatment at 1000 to 1200 ° C. is formed on a semiconductor silicon wafer 1 by using the method of interstitial oxygen precipitation treatment in a semiconductor silicon wafer according to the first embodiment of the present invention. FIG. 2 shows the relationship between the density of oxygen precipitation defects inside the semiconductor silicon wafer, the leak failure index, and the position of the semiconductor silicon wafer 1 placed on the high-purity quartz boat 2.

The oxygen precipitation defect density inside the semiconductor silicon wafer on which the N-MOS type DRAM was formed was put on the high purity quartz boat 2 in the interstitial oxygen precipitation treatment method in the semiconductor silicon wafer of the first embodiment. 650 ° C. regardless of the position of the semiconductor silicon wafer 1, that is, the positions of the semiconductor silicon wafers C and D shown in FIG.
, The heat history is kept uniform, and the leak failure index is reduced and stabilized.

Next, a description will be given of a second embodiment of the method for interstitial oxygen precipitation in a semiconductor silicon wafer according to the present invention. In this embodiment, the furnace body temperature of the thermal diffusion furnace 3 was raised and lowered at a rate of 5.0 ° C./min.
It is used as a pre-process for forming an S-type DRAM. C-MOS
Since it has a high-temperature heat treatment of 1000 to 1200 ° C. in the heat treatment in the semiconductor manufacturing process for forming the type DRAM,
Does not require many potential defects inside the semiconductor silicon wafer. That is, latent defects are suppressed by increasing the rate of temperature rise and fall of the furnace body temperature. Oxygen precipitation defect density, leak failure index and high purity inside a semiconductor silicon wafer after forming a C-MOS type DRAM on a semiconductor silicon wafer 1 using interstitial oxygen precipitation processing in the semiconductor silicon wafer of this embodiment. FIG. 3 shows the relationship with the position of the semiconductor silicon wafer 1 placed on the quartz boat 2.
Shown in The density of the oxygen precipitation defects inside the semiconductor silicon wafer on which the C-MOS type DRAM was formed is determined by the semiconductor silicon wafer placed on the high-purity quartz boat 2 in the interstitial oxygen precipitation treatment method in the semiconductor silicon wafer of the second embodiment. Irrespective of the position of 1, the heat history at 650 ° C. is uniform, so that the heat history is kept almost uniform, and the leak failure index is stabilized.

[0009]

As described above, according to the present invention, in a method for interstitial oxygen precipitation in a semiconductor silicon wafer at 650 ° C. using a thermal diffusion furnace, the semiconductor silicon wafer placed on a high-purity quartz boat is Temperature 450 ± 10
By entering the furnace into and out of the furnace, the treatment at 650 ° C. for a certain time was made uniform regardless of the position of the semiconductor silicon wafer placed on the high-purity quartz boat. In other words, a certain density of oxygen precipitation defects can be obtained inside the semiconductor silicon wafer that has undergone the heat treatment in the semiconductor manufacturing process, and the oxygen precipitation defects cause contaminant impurities that cause leak failure by performing proper gettering. Is removed, and as a result, a stable yield is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the position of a semiconductor silicon wafer according to the first embodiment of the present invention and the oxygen precipitation defect density and the leak failure index.

FIG. 3 is a diagram showing a relationship between a position of a semiconductor silicon wafer, an oxygen precipitation defect density, and a leak failure index according to a second embodiment of the present invention.

FIG. 4 is a diagram for explaining a conventional example.

FIG. 5 is a diagram showing the relationship between the position of a conventional semiconductor silicon wafer, the density of oxygen precipitation defects, and the leak failure index.

[Explanation of symbols]

 Reference Signs List 1 semiconductor silicon wafer 2 high-purity quartz boat 3 thermal diffusion furnace 4 heater

Claims (1)

(57) [Claims] 1. A plurality of semiconductor silicon mounted on a boat
In the heat diffusion furnace, heat treatment is performed to precipitate interstitial oxygen in the semiconductor silicon wafer, and a plurality of semiconductor silicon wafers mounted on the boat are heated to 450 ± 10 ° C. After entering the heat diffusion furnace, the temperature was raised at a rate of 0.5 to 5.0 ° C./min to 6
After treatment at 50 ° C. for a certain time, 0.5-5.0 ° C./mi
A method of precipitating interstitial oxygen in a semiconductor silicon wafer, wherein the temperature is lowered at a rate of n and the furnace is discharged at 450 ± 10 ° C.