JPH0787191B2 - Semiconductor processing equipment using plasma - Google Patents

Description

The present invention relates to a semiconductor processing apparatus using plasma, and more particularly to an interlock for limiting power supply to a cathode electrode by the pressure in an airtight container. Regarding the mechanism.

(Prior Art) In recent years, a semiconductor processing apparatus that uses gas plasma to perform, for example, a film forming process or an etching process on a substrate such as a semiconductor wafer has been actively used.

In such a semiconductor processing apparatus, a pair of electrodes are provided in a high-vacuum airtight container, and a reaction gas such as argon gas introduced into the airtight container is turned into plasma, and the reaction components in the gas plasma are used to generate a substrate Semiconductor processing such as film forming processing and etching processing is performed. For example, in a sputtering device, the airtight container is evacuated to 10 ^-6 Torr, and then a reaction gas such as argon gas is introduced to, for example, 10 ^-2 to 10 ^-3 To
I was working in a vacuum state of rr.

(Problems to be Solved by the Invention) However, in a semiconductor processing apparatus using plasma as described above, for example, in a sputtering apparatus, power is supplied to the electrodes at an initial vacuum degree of 10 ⁻⁶ Torr in the airtight container. If argon gas is introduced after that, abnormal discharge such as arc discharge may occur depending on the conditions, and this abnormal discharge may damage the target, for example, and cause the broken pieces to adhere to the substrate, resulting in poor yield in semiconductor manufacturing. It was

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a semiconductor processing apparatus using plasma capable of preventing abnormal discharge in an airtight container and improving yield in semiconductor manufacturing. And

[Structure of the Invention] (Means for Solving the Problems) According to the present invention, an airtight container, a pair of electrodes provided in the container, and electric power are supplied to the pair of electrodes. A power supply, a gas supply device for supplying gas into the container, a vacuum gauge connected to the container for detecting the pressure in the container, and a detection signal of the pressure of the vacuum gauge is input, and at least the inside of the container When the pressure is in a pressure region where abnormal discharge is generated between the electrodes, the supply of electric power from the power source to the electrodes is blocked, and when the degree of vacuum in the container reaches a predetermined degree of vacuum, A semiconductor processing apparatus using plasma, characterized in that it is provided with an interlock circuit for automatically supplying electric power from the power source to the electrodes.

(Operation) In the present invention, an abnormal discharge in the vicinity of the electrodes can be prevented by providing an interlock mechanism that limits the supply of power at a vacuum level other than a vacuum level suitable for work while monitoring the vacuum level in the airtight container, In addition, the power supply can be started by automatically releasing the interlock mechanism after passing the abnormal discharge occurrence region.

(Example) An example in which the present invention is applied to a magnetron sputtering apparatus will be described below with reference to the drawings.

The cylindrical airtight container 1 has a cylindrical wafer processing chamber, for example, a wafer loading / unloading chamber 2, an etching processing chamber 3, a wafer heating processing chamber 4, a first sputtering processing chamber 5, and a second sputtering processing chamber 5.
The sputtering processing chambers 6 are concentrically arranged side by side in the order of semiconductor wafer processing steps. The semiconductor wafer inserted from the wafer loading / unloading chamber 2 is sequentially moved through the processing chambers and undergoes a series of processing. Needless to say, the number and arrangement of these processing chambers may differ depending on the purpose of wafer processing.

A more specific structure of the sputter processing chamber will be described with reference to FIG. A sputter section 8 is provided in the sputter processing chamber 7 arranged in the airtight container 1, and a semiconductor wafer 9 is arranged so as to face the sputter section 8.

In this embodiment, a magnetron cathode having an inverted conical ring-shaped target 10 is used in the sputter part 8. That is, the target 10 has a target surface formed in an inverted conical ring shape. One pole, for example, an N magnetic pole 11 is provided in the center of the target 10, and the other magnetic pole, for example, an S magnetic pole 12 is annularly provided outside the outer periphery of the target 10. Due to the action of the S magnetic pole 12 and the N magnetic pole 11 at the center of the target 10, an arc-shaped magnetic field B is formed in the vicinity of the sputtering surface of the target 10. The arc-shaped magnetic pole B acts to temporarily confine the activated ions. A heater block 13 for preheating the wafer is provided on the back surface of the semiconductor wafer 9, and an introducing pipe 14 for a reaction gas such as argon gas penetrates through the heater block 13 and communicates with the inside of the airtight container 1. It is provided to do. A heater block is provided in the airtight container 1.
A reaction gas is introduced from an outlet formed on the outer side of the semiconductor wafer above 13.

An example of the operation of the sputtering apparatus having such a configuration will be described.

While the semiconductor wafer 9 is being heated by the heater block 13, the inside of the airtight container 1 is evacuated to a high vacuum of, for example, about 10 ⁻⁶ Torr by the vacuum pump 22, and then the reaction gas generated by the reaction gas generator 20 such as argon gas is gas. Airtight container 1 from the introduction pipe 14
The reaction gas introduced into the target 10 is turned into plasma by applying high-frequency power of 13.75 MHz, for example, from the power source 21 to the target 10 according to a predetermined program. The reaction gas turned into plasma is confined in a donut shape near the sputtering surface by the magnetic field B generated near the sputtering surface of the target 10 as shown by A in the figure. At this time, the reaction gas turned into plasma is sputtered on the target 10 and the particles 15 flying there are attached to the semiconductor wafer 9 to form a thin film.

The atmosphere in the airtight container 1 is maintained at a high vacuum by the vacuum pump 22, and the degree of vacuum can be constantly detected by the vacuum gauge 23. The measurement value signal detected by the vacuum gauge 23 is adapted to be input to the interlock circuit 24, and the power is not applied to the target 10 at a vacuum degree other than the vacuum degree preset by the interlock circuit 24. There is.

By the way, in the sputtering operation, the degree of vacuum in the airtight container 1 is first lowered to 10 ^-6 Torr as described above, and then a reaction gas such as argon gas is introduced to maintain an atmosphere of about 10 ^-2 to 10 ^-3 Torr. However, if argon gas is introduced after applying electric power to the target 10 in an atmosphere of a vacuum higher than 10 ^-3 Torr, abnormal discharge such as arc discharge occurs and the target 10 is damaged. There is a problem that the broken pieces adhere to the semiconductor wafer 9. Therefore, in this embodiment, by providing an interlock circuit 24 that operates based on a signal from the vacuum gauge 23 so that power is not supplied at a vacuum level where the vacuum level in the airtight container 1 becomes an abnormal discharge generation region. It solves the above problem. It is preferable that the interlock circuit has a function of automatically releasing the interlock mechanism and starting power supply after the abnormal discharge generation region has passed.

In the above-mentioned embodiments, the present invention is applied to the sputtering apparatus. However, it is needless to say that the present invention can be applied to any semiconductor processing apparatus using plasma, such as a plasma etching apparatus and a sputter etching apparatus. .

[Effects of the Invention] As described above, according to the semiconductor processing apparatus to which the present invention is applied, the occurrence of abnormal discharge near the electrodes can be prevented, and the problems such as the generation of foreign matter due to electrode damage can be solved. There is an effect that the yield can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a sputtering apparatus according to the present invention, and FIG. 2 is a view showing a structure of a sputtering processing chamber of an embodiment. 1 ... Airtight container, 7 ... Sputtering chamber, 8 ... Sputtering part, 9 ... Semiconductor wafer, 10 ... Target, 11 ...
N magnetic pole, 12 ... S magnetic pole, 14 ... Reactive gas introduction tube, 15 ...
Flying particles, 20 ... Reactive gas generator, 21 ... Power supply, 22 ...
… Vacuum pump, 23 …… vacuum gauge, 24 …… Interlock circuit.

Claims (1)

[Claims] 1. An airtight container, a pair of electrodes provided in the container, a power supply for supplying electric power to the pair of electrodes, and a gas supply device for supplying gas into the container. A vacuum gauge connected to the container for detecting the pressure in the container, and a detection signal of the pressure of the vacuum gauge are input, and at least the pressure in the container is in a pressure region where abnormal discharge is generated between the electrodes. In the case, an interlock circuit that blocks the supply of electric power from the power source to the electrodes and automatically supplies the electric power from the power source to the electrodes when the degree of vacuum in the container reaches a predetermined degree of vacuum. And a semiconductor processing apparatus using plasma.