KR200222594Y1 - Automatic pressure control system of wafer depositor - Google Patents

Abstract

The present invention relates to a system for automatically adjusting the pressure difference between the reaction chamber 10 and the load lock chamber 30 prior to the lifting of the boat 40 during the wafer deposition process, the reaction chamber 10 that can proceed the deposition process (10) )and; A load lock chamber 30 installed below the reaction chamber 10 to remove oxygen gas introduced before the deposition process; A shutter 31 for isolating the reaction chamber 10 and the load lock chamber 30; A boat 40 for stacking and moving the wafer 1 into the reaction chamber 10 and the load lock chamber 30; A reaction chamber exhaust pipe 14 and a load lock chamber exhaust pipe 34 extending from the reaction chamber 10 and the load lock chamber 30, respectively; A plurality of pressure gauges 14a, 30a, 34a for sensing the pressure of each part; A plurality of flow controllers (18) (35a) (35b) for respectively regulating the pressure of each part to atmospheric pressure; A central control unit (C) configured to compare the input values of the pressure gauges (14a) (30a) and (34a) and automatically control the flow controllers (18) (35a) (35b) according to the result. The control unit C automatically opens and closes the flow controllers 18, 35a and 35b to maintain the same pressure between the reaction chamber 10 and the load lock chamber 30, thereby prolonging the time taken by manual operation of the conventional valve. The present invention relates to an automatic pressure control system for a wafer deposition apparatus capable of preventing the occurrence of contact resistance by reducing the growth of a natural oxide film on the surface of the wafer 1 and minimizing waste of unnecessary manpower.

Description

AUTOMATIC PRESSURE CONTROL SYSTEM OF WAFER DEPOSITOR}

The present invention relates to a system for automatically adjusting the pressure difference between the reaction chamber and the load lock chamber before the boat is lifted and lifted during the wafer deposition process. The present invention relates to an automatic pressure control system for a wafer deposition apparatus, which minimizes unnecessary waste of manpower.

In the conventional conventional wafer deposition apparatus, as illustrated in FIG. 1, a cylindrical inner tube 11 and a cap-shaped outer tube 12 are disposed to overlap each other, and a lower portion of the reaction gas communicates with the inner tube 11. A reaction chamber (13b) provided between the inlet port (13a) and the inner and outer tubes (11) (12), the reaction chamber (Process Chamber) 10 to proceed with the vapor deposition process; A load lock room 30 formed below the reaction chamber 10 to remove oxygen before the process proceeds; A shutter 31 for isolating the load lock chamber 30 and the reaction chamber 10; It consists of the boat 40 which moves the load lock chamber 30 and the wafer 1 laminated | stacked in the reaction chamber 10 up and down.

In addition, when the wafer 1 is loaded or unloaded from the load lock chamber 30 into the reaction chamber 10, pressure gauges 14a and 30a for detecting an atmospheric pressure difference therebetween are provided in the reaction chamber 10. It is provided in the exhaust pipe 14 and the load lock chamber 30, respectively, the exhaust pipe 34 of the load lock chamber 30 is provided with a pressure gauge 34a for detecting whether the exhaust pipe 34 is overpressure, A needle valve 15 is installed outside the reaction chamber exhaust pipe 14 to adjust the pressure difference identified by the pressure gauge 14a to a normal state, and the load lock chamber 30 has an amount of nitrogen gas introduced therein. A mass flow controller (MFC) 35a (35b) is installed to adjust the flow rate. In the drawings, reference numeral 16 denotes a main valve installed in the reaction chamber exhaust pipe 14, 17 denotes a pneumatic valve, and 36 denotes a gate valve.

In the wafer deposition apparatus, as the boat 40 rises into the inner tube 11, external air is also introduced to grow a natural oxide film on the wafer 1, which is typically partially partially polished on the silicon wafer 1. When the oxide film is grown or is not grown at all, the quartz tube of the diffusion furnace is controlled at a temperature of about 900 to 1200 ° C. to coat the oxide film on the surface of the wafer 1. For 30 minutes to several hours in a boat), an oxide film of thousands of A ° (1A ° = 10-8 cm) is formed by using an oxidant, that is, oxygen gas or steam, or hydrogen and oxygen gas. When silicon is oxidized, an oxide film ( Layer of SiO 2) is formed. This oxide film protects the surface of the wafer 1 as a mask in an impurity diffusion process and at the same time, for photo engraving.

In order to allow the boat 40 to be loaded or unloaded from the load lock chamber 30 into the reaction chamber 10 before or after the vapor deposition process, the pressure gauges 14a and 30a may be at atmospheric pressure. In addition, overpressure should not occur in the pressure gauge 34a, and the pressure difference recognized by the pressure gauges 14a and 30a should be kept below a predetermined value.

The process of the conventional wafer deposition apparatus loads the wafer 1 on the boat 40 and then exhausts it through the load lock chamber exhaust pipe 34 so that the inside of the load lock chamber 30 can be maintained in a vacuum state, and oxygen Checking the amount of oxygen gas in the load lock chamber 30 through a test for the presence of gas, and then the pressure of the load lock chamber 30 by appropriately adjusting the flow rate of nitrogen gas using the flow controller (35a, 35b) Is maintained at atmospheric pressure. When the load lock chamber 30 maintains the atmospheric pressure as described above, the shutter 40 closing the load lock chamber 30 and the reaction chamber 10 is opened while the boat 40 enters the reaction chamber 10. When the entrance of the boat 40 is completed, the deposition process in the reaction chamber 10 proceeds. When the pressure in the reaction chamber 10 maintains the atmospheric pressure after the deposition process is completed, the shutter ( 31 is open and the boat 40 is to be lowered.

According to the above, in order for the shutter 31 to be opened, the load lock chamber 30 and the reaction chamber 10 should maintain atmospheric pressure, and the load lock chamber 30 and the load lock chamber exhaust pipe 34 should not be overloaded. The pressure difference between the load lock chamber 30 and the reaction chamber 10 should be within a predetermined range, that is, 0.02. If the pressure difference between the load lock chamber 30 and the reaction chamber 10 is 0.02 or more, the needle valve 15 ) To create an environment where the process can proceed.

However, in the conventional wafer deposition apparatus, even if the pressure difference between the load lock chamber 30 and the reaction chamber 10 is controlled by the needle valve 15, the same method is used when the apparatus is used for a long time or when the cleaning apparatus is maintained. There is a problem that the pressure state is changed, and thus, in each of these cases, the pressure has to be manually readjusted equally, and thus, unnecessary manpower is required.

In addition, when an error occurs before the deposition process proceeds, there is a concern that the natural oxide film may increase as the time delay is delayed.

In addition, even when the unloading of the boat 40 is not performed from the high temperature reaction chamber 10 due to the inconsistency of dynamic pressure after the deposition process, there is a problem that adversely affects the wafer 1.

Therefore, the present invention was devised to solve the above-mentioned problems, and it is possible to reduce the growth of the natural oxide film on the surface of the wafer according to the prolonged action time, thereby suppressing the generation of contact resistance and minimizing unnecessary waste of manpower. It is an object of the present invention to provide an automatic pressure control system for a wafer deposition apparatus.

1 is a cross-sectional view showing a wafer deposition apparatus according to the prior art and a pressure regulating system applied thereto;

2 is a cross-sectional view showing a wafer deposition apparatus and an automatic pressure control system applied thereto according to the present invention;

Figure 3 is a block diagram schematically showing the configuration of the central control unit for the flow controller of the automatic pressure regulation system applied to the present invention,

Figure 4 is a circuit diagram of an automatic pressure control system applied to the present invention.

** Description of symbols for the main parts of the drawing **

C; Central control unit 1; wafer

10; Reaction chamber 11; Inner tube

12; Outer tube 13a; Reaction gas inlet

13b; Reactive gas exhaust 14; Reaction chamber exhaust pipe

14a, 30a, 34a; Pressure gauge 16; Main valve

17; Pneumatic valves 18, 35a, 35b; Flow controller

30; Load lock chamber 31; shutter

34; Load lock chamber exhaust pipe 40; boat

Automatic pressure control system of the wafer deposition apparatus according to the present invention for achieving the above object and the reaction chamber to proceed with the deposition process; A load lock chamber installed under the reaction chamber to remove oxygen gas introduced before the deposition process; A shutter for isolating the reaction chamber and the load lock chamber; A boat configured to move the wafer in and out of the reaction chamber and the load lock chamber; A reaction chamber exhaust pipe and a load lock chamber exhaust pipe respectively extending from the reaction chamber and the load lock chamber; A pressure gauge installed in the load lock chamber to measure the pressure, a pressure gauge installed on the reaction chamber exhaust pipe, and a pressure gauge installed on the load lock chamber exhaust pipe to measure the pressure; A plurality of flow controllers respectively connected to the reaction chamber exhaust pipe and the load lock chamber to adjust pressures of the reaction chamber and the load lock chamber to atmospheric pressure, respectively; When the input values of the pressure gauges are compared with the set values, respectively, the flow controller corresponding to the set value is larger than the set value, and the corresponding flow controller is closed when the value is smaller than the set value, and the reaction chamber and the load lock chamber are closed. Pressure to send a control signal to the central controller so that the loading and unloading control of the boat is made only when the pressure of the load lock chamber pressure gauge is greater than the pressure of the load lock chamber exhaust pipe pressure gauge. Characterized in that it consists of a control unit.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the present invention preferentially replaces and installs another flow controller 18 instead of the needle valve 15 shown in the related art, and a central control unit C for controlling the overall control. Is installed separately. The central control unit C corresponds to an arithmetic unit for controlling by using the pressure value measured by the pressure gauges 14a and 30a.

In more detail, the automatic pressure control system of the wafer deposition apparatus according to the present invention is a reaction chamber 10 to proceed with the deposition process; A load lock chamber 30 installed below the reaction chamber 10 to remove oxygen gas introduced before the deposition process; A shutter 31 for isolating the reaction chamber 10 and the load lock chamber 30; A boat 40 for stacking and moving the wafer 1 into the reaction chamber 10 and the load lock chamber 30; A reaction chamber exhaust pipe 14 and a load lock chamber exhaust pipe 34 extending from the reaction chamber 10 and the load lock chamber 30, respectively; A plurality of pressure gauges 14a, 30a, 34a for sensing the pressure of each part; A plurality of flow controllers (18) (35a) (35b) for respectively regulating the pressure of each part to atmospheric pressure; Comparing the input value of each of the pressure gauges (14a) (30a) (34a) and the central control unit (C) for automatically controlling the flow controllers (18, 35a, 35b) according to the result.

Figure 3 schematically shows a connection state of the central control unit (C) for controlling each flow controller 18, 35a, 35b in the automatic pressure regulation system applied to the present invention.

As shown in the circuit diagram shown in FIG. 4, the central controller C compares the set values with the values of the pressure gauges 14a, 30a, and 34a, respectively, and is larger than the set values. When the flow controller is opened and the flow controller is smaller than the set value, the flow controller is closed to automatically adjust the pressure difference between the reaction chamber 10 and the load lock chamber 30.

That is, when the internal pressure is larger than the basic pressure set value by comparing the basic pressure set value of the reaction chamber 10 with the value measured from the pressure gauge 14a through the comparator, the flow controller 18 is opened, and the basic When the internal pressure is smaller than the pressure set value, the flow controller 18 is closed. In addition, the flow rate controller 35a of the load lock chamber 30 when the internal pressure is larger than the basic pressure set value by comparing the basic pressure set value of the load lock chamber 30 with the value measured from the pressure gauge 30a through a comparator. ) 35b is opened and the flow controllers 35a and 35b are closed when the internal pressure is smaller than the basic pressure set value.

On the other hand, in order to open the shutter 31 so that the wafer 1 can be loaded or unloaded into the boat 40, the pressure gauges 14a of the load lock chamber 30 and the reaction chamber 10 are opened. (30a) (34a) by comparing the value of the pressure difference is smaller than the allowable value and the value of each pressure gauge (30a, 34a) of the load lock chamber 30 and the load lock chamber exhaust pipe (34) The condition that the pressure of the load lock chamber 30 is large must be satisfied at the same time.

That is, the pressure measurement value of the reaction chamber 10 is compared with the pressure measurement value of the load lock chamber 30, and the pressure value of the reaction chamber 10 is smaller than 0.02 compared to the pressure value of the load lock chamber 30, and the rod The boat 40 is loaded and unloaded only when the pressure measurement value of the lock chamber 30 is compared with the pressure measurement value of the load lock chamber exhaust pipe 34 to simultaneously satisfy the condition that the pressure of the load lock chamber 30 is large. You lose.

Since a series of operations as described above are made, the same pressure may be always formed between the reaction chamber 10 and the load lock chamber 30.

Effects of the present invention that can be expected by the configuration and action as described above are as follows.

In the automatic pressure control system of the wafer deposition apparatus according to the present invention, the flow controllers 18, 35a, 35b are automatically opened and closed by the control of the central controller C, and the reaction chamber 10 and the load lock chamber 30 are controlled. By keeping the pressure always the same state, it is possible to prevent the prolongation of the action time by the manual operation of the needle valve 15, which has been a problem of the prior art, thereby reducing the growth of the natural oxide film on the surface of the wafer 1 There is an advantage that can suppress the generation of contact resistance, minimizing unnecessary waste of manpower.

Claims (1)

A reaction chamber capable of carrying out a deposition process; A load lock chamber installed under the reaction chamber to remove oxygen gas introduced before the deposition process; A shutter for isolating the reaction chamber and the load lock chamber; A boat configured to move the wafer in and out of the reaction chamber and the load lock chamber; A reaction chamber exhaust pipe and a load lock chamber exhaust pipe respectively extending from the reaction chamber and the load lock chamber; A pressure gauge installed in the load lock chamber to measure the pressure, a pressure gauge installed on the reaction chamber exhaust pipe, and a pressure gauge installed on the load lock chamber exhaust pipe to measure the pressure; A plurality of flow controllers respectively connected to the reaction chamber exhaust pipe and the load lock chamber to adjust pressures of the reaction chamber and the load lock chamber to atmospheric pressure, respectively; When the input values of the pressure gauges are compared with the set values, respectively, the flow controller corresponding to the set value is larger than the set value, and the corresponding flow controller is closed when the value is smaller than the set value, and the reaction chamber and the load lock chamber are closed. Pressure to send a control signal to the central controller so that the loading and unloading control of the boat is made only when the pressure of the load lock chamber pressure gauge is greater than the pressure of the load lock chamber exhaust pipe pressure gauge. Automatic pressure control system of the wafer deposition apparatus, characterized in that consisting of a control unit.