KR20030047278A - Sputtering apparatus - Google Patents

Abstract

PURPOSE: A sputtering apparatus is provided to be capable of preventing the contamination of a semiconductor substrate due to the generation of foreign substance by uniformly conserving the temperature of a quartz window by using a halogen lamp. CONSTITUTION: A layer is formed on a substrate(900) by a sputtering process in a sputtering chamber(200). A plate(202) for loading the substrate(900) is located opposite to the front surface of a target(204) in the sputtering chamber(200). A quartz window(208) is installed on the upper portion of the sputtering chamber. An induction coil(210) is installed to surround the quartz window for supplying electric field into the sputtering chamber through the quartz window. A heating part is installed at the upper portion of the sputtering chamber for uniformly conserving the temperature of the quartz window which is non-uniformly heated by RF(Radio Frequency) power supplied from the induction coil. Preferably, the heating part is provided with a halogen lamp(218) and a reflecting plate(220) for reflecting the beam irradiated from the halogen lamp to the quartz window.

Description

Sputtering apparatus

The present invention relates to a sputtering apparatus used in a semiconductor device manufacturing process. More specifically, the present invention relates to a sputtering apparatus for forming a film on a semiconductor substrate using plasma.

In recent years, the manufacturing technology of semiconductor devices has been developed in the direction of improving integration, reliability, processing speed, etc. with the rapid development of information and communication technology. The semiconductor device is manufactured by forming a multilayer film on a wafer using a semiconductor substrate, and forming the multilayer film in a pattern having electrical properties.

The pattern is formed by repeatedly performing unit processes such as deposition, photolithography, etching, polishing, cleaning, inspection, and the like. In a recent semiconductor device manufacturing process requiring a design rule of 0.15 μm or less, precise control of the process conditions applied to the unit processes is required to form a fine pattern.

Among the unit processes, a deposition process is a process of forming a film on a semiconductor substrate, and may be roughly classified into physical vapor deposition and chemical vapor deposition. Among them, the physical vapor deposition is a processing technology in which particles having high energy are collided with a target formed of a target material to be stacked, and the target material is separated from the target to stack the target material on a semiconductor substrate. Such physical vapor deposition is divided into sputtering and vacuum deposition. In recent years, the sputtering is mainly used in the manufacture of semiconductor devices.

The sputtering processing technology can stack a film having a uniform thickness in a large area, can easily control the thickness of the film, and can easily stack a film having an alloying component as compared with the vacuum deposition, and is laminated on a semiconductor substrate. It has the advantage of ensuring excellent step coverage, grain structure and stress of the film.

As an example of an apparatus and a film forming method using the above sputtering technique, US Pat. No. 4,894,132 issued to Tanaka discloses sputtering a target material on a semiconductor substrate by glow discharge. Methods and apparatus are disclosed and US Pat. No. 4,933,063 (issued to Katsura, et al.) Discloses a vacuum chamber, a target provided in the vacuum chamber, a protective plate provided to surround the target, and a substrate holder on which the substrate is placed. A sputtering apparatus is disclosed that includes a holder, a heater for heating the protective plate and the substrate holder to a set temperature.

1 is a schematic configuration diagram for explaining the sputtering apparatus as described above.

Referring to FIG. 1, a plate 102 in which a semiconductor substrate 900 is placed is provided in a chamber 100 where a sputtering process is performed, and a material to be stacked on the semiconductor substrate 900 on the plate 102. A target 104 and a backing plate 106 supporting the target 104 are formed. The upper portion of the chamber 100 is provided with a quartz window 108 having a dome shape, and a housing 112 containing an induction coil 110 is provided around the quartz window 108.

By the operation of a vacuum pump (not shown) connected to the exhaust port 114 provided on one side of the chamber 100, the inside of the chamber 100 is formed in a vacuum, and the sputtering gas is formed through the gas supply pipe 116. When provided inside, RF power is applied to the induction coil 110 to form the sputtering gas in a plasma state. The positive ion particles of the sputtering gas formed in the plasma state by the RF power impinge on the front surface of the target 104 by the negative voltage applied to the backing plate 106, and thus the sputter sputtered from the front surface of the target 104. Particles are deposited on the semiconductor substrate 900.

When a plurality of semiconductor substrates are repeatedly processed using the sputtering apparatus as described above, RF power is applied to the induction coil while the semiconductor substrate is loaded into the chamber and the sputtering process is performed. RF power is not applied until it is unloaded and a new semiconductor substrate is loaded. That is, RF power is applied during the process and RF power is not applied during the pre-process or post-process time. At this time, the temperature of the quartz window becomes uneven due to the repeated application of RF power, and foreign substances generated during the process and adhered to the quartz window are peeled off from the quartz window due to the repeated temperature change. As described above, the exfoliated foreign matters float in the chamber and adhere to the semiconductor substrate during the process to generate process defects. The process defects act as a cause of lowering the reliability of the semiconductor device and lowering the production yield.

In order to solve the above problems, the present invention provides a sputtering apparatus having an induction coil and a quartz window to which RF power is applied, wherein the sputtering apparatus prevents the generation of foreign substances contaminating a semiconductor substrate by maintaining a constant temperature of the quartz window. To provide.

1 is a schematic configuration diagram illustrating a conventional sputtering apparatus.

2 is a schematic diagram illustrating a sputtering apparatus according to an embodiment of the present invention.

3 is a view for explaining the internal structure of the housing shown in FIG.

4 is a block diagram for describing a control unit of the sputtering apparatus shown in FIG. 2.

Explanation of symbols on the main parts of the drawings

100, 200: chamber 102, 202: plate

104, 204: target 106, 206; Backing plate

108, 208: quartz window 110, 210: induction coil

112, 212: housing 114, 214: exhaust port

116, 216: gas supply pipe 202a: heater block

202b: hot plate 218: halogen lamp

220: reflector 222: fixing bolt

224: temperature sensor 226: control unit

226a: process control unit 226b: temperature control unit

228: power supply 230: RF power

232: display unit 234: buzzer

900: semiconductor substrate

The present invention for achieving the above object,

A sputtering chamber provided with a sputtering gas, the plate on which the substrate is placed and the front surface of the target facing each other, and sputtering particles sputtered from the front surface of the target stacked on the substrate to form a film;

An induction coil provided to surround a quartz window covering an upper portion of the sputtering chamber, forming an electric field for forming the sputtering gas into a plasma state, and providing the electric field into the sputtering chamber through the quartz window;

And a heating means provided above the sputtering chamber and configured to maintain a constant temperature of the quartz window that is non-uniformly heated by RF power provided to the induction coil.

As an example, the sputtering apparatus may include a housing in which the induction coil is embedded, a temperature sensor provided inside the housing, and a temperature sensor for measuring a temperature of the quartz window, and a temperature signal detected by the temperature sensor. It further includes a control unit for controlling the operation.

The heating means includes a halogen lamp provided above the sputtering chamber, and a reflecting plate provided above the halogen lamp and directing light emitted from the halogen lamp to the quartz window.

The controller controls the lighting of the halogen lamp and the power provided to the halogen lamp according to the temperature signal transmitted from the temperature sensor. That is, the halogen lamp is turned off while the substrate is loaded into the sputtering chamber and the process is in progress. When the substrate is unloaded after the process is finished, the halogen lamp is turned on, and the power provided to the halogen lamp is controlled.

Therefore, the temperature of the quartz window is always kept constant, and prevents the peeling phenomenon of foreign matters attached to the inside of the quartz window.

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

2 is a schematic diagram illustrating a sputtering apparatus according to an embodiment of the present invention. 3 is a view for explaining the internal structure of the housing shown in FIG.

2 and 3, a plate 202 on which a semiconductor substrate 900 is placed is provided in a chamber 200 where a sputtering process is performed, and an upper portion of the plate 202 is disposed on a semiconductor substrate 900. A target 204 formed of a material to be stacked and a backing plate 206 supporting the target 204 are provided. Plate 202 is a heater block (202a) for excluding the influence on the moisture of the sputtering gas provided into the chamber 200, and for heating the semiconductor substrate 900 to a temperature suitable for the deposition of sputter particles and And a hot plate 202b disposed on the heater block 202a. Inside the heater block 202a is provided a heating wire that is heated by the application of power. Argon gas is used as the sputtering gas, and the target 204 is formed of aluminum, titanium, or the like depending on the type of film to be laminated. In addition, a quartz window 208 having a dome shape is provided at the upper portion of the chamber 200, and a housing 212 in which the induction coil 210 is embedded is provided around the quartz window 208. At this time, the induction coil 210 is fixed to the inner wall of the housing 212 is provided to surround the quartz window 208.

By the operation of a vacuum pump (not shown) connected to the exhaust port 214 provided at one side of the chamber 200, the inside of the chamber 200 is formed in a vacuum, and the sputtering gas is formed through the gas supply pipe 216. When provided inside, RF power is applied to the induction coil 210 to form the sputtering gas into a plasma state. When RF power is applied to the induction coil 210, the induction coil 210 forms an electric field, and sputtering gas is ionized by the electric field to form a plasma state. The positive ion particles of the sputtering gas formed in the plasma state by the RF power impinge on the front surface of the target 204 by the negative voltage applied to the backing plate 206, and thus the sputter sputtered from the front surface of the target 204. Particles are deposited on the semiconductor substrate 900. At this time, a positive voltage is applied to the chamber 200 to selectively induce only positive ion particles to the target 204. The quartz window 208 divides the inside of the chamber 200 and the region where the induction coil 210 is provided so that the induction coil 210 is not exposed to the plasma.

The upper portion of the quartz window 208 is provided with a halogen lamp 218 to keep the temperature of the quartz window 208 constant. Halogen lamps 218 are provided radially in number to uniformly heat the quartz window 208. In addition, a reflector 220 for inducing light emitted from the halogen lamp 218 to the quartz window 208 is provided on the upper portion of the halogen lamp 218. That is, the reflective plate 220 is fixed to the upper portion of the housing 212 by the fixing bolt 222, and the halogen lamp 218 is fixed to the reflective plate 220. The central portion of the reflector 220 is provided with a temperature sensor 224 for sensing a temperature inside the housing 212. Various types of temperature sensors 224 may be used, and a thermocouple thermometer is used in the present invention.

In the case where the sputtering process for a plurality of semiconductor substrates is repeatedly performed using the sputtering apparatus as described above, first, when the semiconductor substrate 900 is loaded into the chamber 200 and seated on the plate 202. The controller 226 properly adjusts the pressure inside the chamber 200 and applies power to the heater block 202a through the power supply 228 to maintain the temperature of the semiconductor substrate 900 properly. Subsequently, a sputtering gas is provided into the chamber 200, and RF power for forming the sputtering gas into a plasma state is applied to the induction coil 210. The positive ion particles of the sputtering gas formed in the plasma state impinge on the front surface of the target 204 by the negative voltage applied to the backing plate 206, so that the sputter particles are sputtered from the front surface of the target 204 to form a semiconductor substrate ( To form a film.

When the sputtering process of forming the film as described above is finished, the provision of the sputtering gas is stopped, and the RF power supply is stopped. In addition, reaction by-products and the like in the chamber 200 are discharged through the exhaust port 214, and the semiconductor substrate 900 after the sputtering process is completed is unloaded from the chamber 200.

At this time, when the provision of the RF power is stopped, the temperature of the quartz window 208 drops, and the temperature sensor 224 detects this. The control unit 226 turns on the halogen lamp 218 through the power supply 228 and maintains the temperature of the quartz window 208 at a predetermined temperature according to the temperature sensing signal of the temperature sensor 224. When a new semiconductor substrate is loaded into the chamber 200 and the sputtering process is performed, RF power is applied to the induction coil 210 and the halogen lamp 218 is turned off.

In the embodiment of the present invention, one thermocouple thermometer is used, but the type and number of temperature sensors do not limit the present invention. In addition, it will be appreciated by those skilled in the art that a method of overcoming the temperature difference with respect to the distance difference between the induction coil and the quartz window generated due to the dome shape of the quartz window can be easily implemented within the scope of the present invention. will be. Similarly, the shape of the quartz window does not limit the invention.

4 is a block diagram for describing a control unit of the sputtering apparatus shown in FIG. 2.

Referring to FIG. 4, when the semiconductor substrate is loaded into the chamber, the process controller 226a provides an RF power source 230 to the induction coil 210 to form a sputtering gas in a plasma state. The sputter particles sputtered from the front surface of the target form a film on the semiconductor substrate by the positive ion particles of the sputtering gas excited in the plasma state collide with the front surface of the target. When the formation of the desired film is finished, the supply of the sputtering gas and the supply of RF power from the RF power supply 230 to the induction coil 210 are stopped. In response to the RF power supply stop signal of the process control unit 226a, the temperature control unit 226b turns on the halogen lamp 218 through the power supply 228 and from the power supply 228 according to the signal of the temperature sensor 224. The degree of emission of the halogen lamp 218 is adjusted. In this case, the temperature sensed by the temperature sensor 224 is configured to be monitored by the operator through the display unit 232, and if an abnormality occurs in the temperature sensor 224, the display unit 232 and the buzzer 234 The operator will notice this with a beep. In addition, even when an abnormality occurs in the halogen lamp 218, the operator can determine through the display unit 232 and the buzzer 234.

Hereinafter, a sputtering process of stacking a titanium film on a semiconductor substrate using the sputtering apparatus will be described in detail.

First, a semiconductor substrate is transferred into a chamber by a transfer robot and loaded on a plate. In this case, the plate is always maintained at a constant temperature in order to increase the time efficiency when processing a plurality of semiconductor substrates.

An argon gas is then provided into the chamber, and RF power is applied to the induction coil to form the argon gas into a plasma state. Positive ion particles in the argon gas in the plasma state collide with the target by a negative voltage applied to the backing plate, thereby sputtering the particles. At this time, the target is formed of a titanium material, a positive voltage is applied to the chamber. The sputtered sputter particles are stacked on a semiconductor substrate to form a titanium film. At this time, the pressure inside the chamber is formed into a vacuum of about 5 × 10 ^-6 Torr by a vacuum pump.

When the titanium film of the desired thickness is formed, the supply of argon gas and the supply of RF power are interrupted by the controller, and the semiconductor substrate is unloaded from the plate to the outside of the chamber. In this case, in order to prevent the quartz window temperature of the upper part of the chamber from changing due to the interruption of the RF power supply, a halogen lamp provided on the upper part of the quartz window is turned on, and the temperature of the quartz window is kept constant by the temperature signal provided by the temperature sensor. do.

Therefore, foreign matters generated during the sputtering process and adhering to the inside of the quartz window are prevented from peeling off due to temperature change.

According to the present invention as described above, in the sputtering process for forming a film on a semiconductor substrate, the induction coil to which RF power is applied to form the sputtering gas in the plasma state heats the quartz window provided on the chamber. During the repetitive processing of a plurality of semiconductor substrates, the temperature of the quartz window, which is changed in accordance with repetitive RF power applied to the induction coil, is kept constant by a halogen lamp which is lit in accordance with a temperature signal provided from a temperature sensor.

Therefore, the peeling of foreign matter adhered to the inside of the quartz window due to the temperature change of the quartz window, and thus the defect occurrence rate of the semiconductor substrate is reduced. Furthermore, there is an effect of improving the reliability and productivity of the semiconductor device.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (3)

A sputtering chamber provided with a sputtering gas, the substrate on which the substrate is placed and the front surface of the target facing each other, and sputtering particles sputtered from the front surface of the target stacked on the substrate to form a film; An induction coil provided to surround a quartz window covering an upper portion of the sputtering chamber, forming an electric field for forming the sputtering gas into a plasma state, and providing the electric field into the sputtering chamber through the quartz window; And And a heating means provided above the sputtering chamber and configured to maintain a constant temperature of the quartz window that is unevenly heated by RF power provided to the induction coil. The apparatus of claim 1, further comprising: a housing in which the induction coil is embedded; A temperature sensor provided inside the housing and configured to measure a temperature of the quartz window; And And a control unit for controlling the operation of the heating means in accordance with the temperature signal sensed by the temperature sensor. The method of claim 1, wherein the heating means, A halogen lamp provided above the sputtering chamber; And And a reflector provided above the halogen lamp, the reflector for directing light emitted from the halogen lamp to the quartz window.