JPS6364894B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in sputtering equipment, particularly sputtering deposition equipment used in semiconductor manufacturing.

When manufacturing semiconductors, silicon oxide (SiO) is used as an interlayer insulating film or protective film on the surface of the semiconductor substrate.
Silicon dioxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ )
In addition, conductors such as metal, polycrystalline silicon, silicide, etc. are deposited as wiring electrodes, but in the former case, the latter is In this case, sputter deposition is often performed using a DC sputter device. In FIG. 1, 1 is a processing chamber, 2 is a semiconductor substrate (wafer), 3 is a target, 4 is a target mounting table, and 5 is a wafer stage. Gas is flowed into the processing chamber 1 from an inlet 6. The inside of the processing chamber is maintained at a reduced pressure of 10 ^-2 to 10 ^-3 Torr. Then, 13.56 MHz high frequency power is applied between the wafer stage 5 and the target mounting table 4 to convert the incoming gas, such as Arcon (Ar) gas, into plasma.
Hit the target, for example, SiO ₂ plate, and release the wafer 2.
Deposit SiO ₂ on top. The target mounting table 4 circulates cooling water to cool down the target 3, which is exposed to the plasma shock and becomes high temperature.In addition, a built-in magnet is installed to increase the sputtering speed (growth speed). It has been previously shown that a magnetic field is created in the plasma to allow electrons to stay there for a long time, increasing the density of the plasma.

However, if the high frequency power is increased too much in order to increase the growth rate, the temperature of the target surface will become too high, and conversely, since the target back surface is cooled from the target mounting table 4, a large temperature stress will be generated inside the target. It happens that it gets destroyed. Insulators such as SiO ₂ plates in particular have poor thermal conductivity, and this tends to be the case, so the sputtering process is done by reducing the power input to an appropriate level. Therefore, the growth rate of spatter deposition is low, the processing time is long, and it is not suitable for mass production.

The present invention aims to solve the problems of the conventional sputtering device and increase the growth rate.The present invention is characterized by the fact that the waveguide connected to the microwave oscillator in the processing chamber is close to the gas inlet. The present invention proposes a sputtering device having a structure provided as follows, and will be described in detail below with reference to the drawings.

FIG. 2 shows a schematic diagram of a sputtering apparatus according to the present invention, in which 10 is a microwave oscillator and 11 is a waveguide coupled thereto. In this way, the microwave waveguide 11 is provided very close to the gas inlet 6, and the microwave oscillator 10, for example,
A 2.45GHz microwave is emitted, which turns the incoming gas into plasma. Since microwaves have a higher plasma generation efficiency than high-frequency waves, the microwaves have already turned into plasma, which enters between the target 3 and the wafer 2, and spatter can be prevented even if the high radio wave power of, for example, 13.56MHz is not increased too much. The same is done. Therefore, in the past, when the gas inflow rate was increased and the degree of vacuum in the processing chamber 1 was lowered to, for example, 10 ^-1 Torr, the plasma density decreased, but in the present invention, the plasma density increases, More target material is thrown off, thus increasing the growth rate. Furthermore, if the amount of gas is large and the plasma density is increased, the mean free path of the electrons becomes shorter and the energy of each electron becomes smaller, so the impact applied to the target is weaker, and therefore the heating of the target is reduced. Therefore, it is no problem to increase the plasma density compared to conventional sputtering equipment.

From these points, the sputtering apparatus according to the present invention can further increase the growth rate, for example.
In an example using a SiO ₂ plate as a target, the growth rate, which was conventionally about 270 Å/min with a high frequency power of 1 KW, can be increased to 1500 Å/min with the application of the same high frequency power, according to the sputtering apparatus according to the present invention. /min.

As is clear from the above explanation, the present invention can excite plasma using microwaves in the processing chamber so that electron energy does not decrease in low vacuum, and can increase the plasma density by more than an order of magnitude to increase the growth rate. The sputtering device greatly improves work efficiency.

In addition, as mentioned above, the energy of each charged particle is fortunately small, which reduces the damage caused to the wafer surface and improves the coverage, which improves the quality of semiconductor devices. There are advantages.

Therefore, the present invention is extremely valuable because it improves mass productivity and also helps improve the quality of semiconductor devices.

The above explanation uses an example of the growth of an insulating film to describe improvements made using a high-frequency sputter, but the present invention can also be applied to a DC sputter used to grow thin films of metal materials such as Al, increasing the growth rate and reducing damage.・It is possible to achieve effects such as improving coverage.

[Brief explanation of drawings]

FIG. 1 shows a schematic sectional view of a conventional sputtering device, and FIG. 2 shows a schematic cross-sectional view of a sputtering device according to the present invention. In the figure, 1 is a processing chamber, 2 is a wafer, 3 is a target, 4 is a target mounting table, 5 is a wafer stage, 6 is a gas inlet, 10 is a microwave oscillator, and 11 is a waveguide.

Claims (1)

[Claims] 1. A sputtering device characterized by having a structure in which plasma is generated by a microwave oscillator in a processing chamber of the high frequency or direct current sputtering device.