KR100301927B1 - High Density Chemical Vapor Deposition Equipment - Google Patents

Abstract

Object: The present invention provides a high density chemical vapor deposition apparatus capable of uniformly supplying a reaction gas to a wafer.

Configuration: The present invention is a chamber that is disposed in the center of the wafer stacking boat to be liftable and the upper side is coated so as to be isolated from the outside air by a cover, and to the outer lower side of the chamber to move up and down the wafer stacking boat up and down A lifter disposed, a wafer entrance formed at one side of the chamber and opened and closed by a door, an exhaust pipe communicating with one side of the chamber to provide an exhaust passage of internal air, and extending from the outside to the inside through the chamber; The distal end of the terminal is composed of a gas injection pipe which is located above the wafer loading boat.

Effect: According to the present invention, the reaction gas injected through the gas injection tube is uniformly supplied over the entire upper surface of the wafer so that the thermally unstable reaction product does not exist as in the prior art.

Description

High Density Chemical Vapor Deposition Equipment

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical vapor deposition apparatus, and more particularly, to high-density chemical vapor deposition, in which electrons obtained by glow discharges collide with gas molecules in a neutral state to be decomposed to obtain desired thin films by a reaction between gases. Method in which the reaction gas is uniformly diffused into the interior of the chamber.

Chemical vapor deposition is a method of decomposing a gaseous compound and inducing a chemical reaction to form a thin film on the wafer surface. Heat, light, plasma, and the like are used as energy sources. This method is determined by temperature range, deposition pressure range, type of energy source and reaction kinetics, and its type is being developed in various ways, but the basic configuration of all chemical vapor deposition apparatus is divided into five parts.

1. Reactor

2. Gas control unit

3. Time and sequence control

4. Heat source for substrate

5. Waste disposal

The detailed construction method of each said part is utilized variously by the advance of the semiconductor manufacturing technique. As an example, the reaction vessel is a horizontal type in which the wafer is placed horizontally in a boat or susceptor, inflows gas into one side of the reaction tube, and is discharged to the other side, and gas flows from top to bottom in the wafer placed on the susceptor. The wafer is placed vertically on the outer or inner surface of the cylinder and the gas is injected from both sides and the cylinder is rotated and the susceptor is rotated. It is subdivided into a gas barrier type that takes a downward injection type such as a vertical type.

In addition, the gas flow rate control unit adjusts the amount of gas flowing into the reactor, the shape of the regulator has a different structure according to the required accuracy. The time and sequence control is the part that oversees the overall operation of the chemical vapor deposition machine. There are many types known from manual to computer controlled fully automatic systems. The heat source is divided into a cold wall type using high frequency energy or ultraviolet energy and a warm wall type using heat resistance. The cold wall type has the advantage that the deposition reaction rate of the reaction vessel is slow while the heating and rising rate of the wafer is fast. In the warm wall type, the deposition of the reactor proceeds at the same or faster rate than the deposition of the wafer and susceptor.

In polycrystalline silicon, silicon oxide, silicon nitride, and the like, which are frequently used in semiconductor processes, polycrystalline silicon is silicon in which single crystals and long crystals are mixed, which is not only when the deposition rate of the substrate is high and the substrate does not have a crystal structure, but also the deposition temperature. Deposition is possible even when the temperature is lower than the minimum temperature required for single crystal growth.

Silicon oxide can be deposited together with arsenic, phosphorus or boron by injection of arsenate, phosphorus hydride or diborane. Silicon nitride is a dense dielectric used to protect circuits composed of contamination-sensitive devices or to oxidize silicon locally.

The thin film obtained through the chemical vapor deposition method is a doped or undoped silicon oxide film, silicon nitride, oxynitride, doped or undoped polysilicon, plasma oxide and plasma nitride.

Among the apparatuses related to chemical vapor deposition described above, the high-density chemical vapor deposition apparatus, which has recently been in the spotlight, has an advantage that the deposition rate is fast and various kinds of thin films can be deposited in a low temperature atmosphere. However, there are also disadvantages such that the neutron-charged particles are strong and easily damaged by radiation, and thermally unstable reaction products tend to remain in the thin film.

Among these shortcomings, thermally unstable reaction products are frequently found in parts where the uniformity of reaction gas diffusion on the wafer surface is poor, especially in the process of forming hemispherical crystal grains (abbreviated as Hemi Spherical Grain: HSG process).

That is, in the conventional high-density chemical vapor deposition apparatus, as shown in FIG. 1, the upper periphery is covered with the high frequency electrode 2, and the gas injection tube 6 is installed on one side of the chamber 4 separated from the outside air. Thus, gas is diffused and supplied to the upper surface of the wafer 10 placed on the boat 8 located in the center of the chamber 4. As the gas is injected into one side of the chamber 4 to be diffused, a non-uniformity of gas density is derived between the portion of the wafer 10 that is close to the gas injection tube 6 and the portion that is far away. Migration will not proceed properly on the wafer surface.

The inventors of the present invention have completed the present invention by diligently examining a solution to solve the disadvantages of the conventional high density chemical vapor deposition apparatus as described above.

Accordingly, an object of the present invention is to provide a high-density chemical vapor deposition apparatus that allows the gas injected into the chamber to be uniformly diffused on the surface of the wafer.

In accordance with the above object, the present invention provides a chamber in which a wafer stacking boat is liftable at an inner center and covered so that the upper side is isolated from outside air by a cover, and the chamber for raising and lowering the wafer stacking boat up and down. A lifter disposed at an outer lower side of the chamber, a wafer entrance formed at one side of the chamber and opened and closed by a door, an exhaust pipe communicating with one side of the chamber to provide an exhaust passage of internal air, and penetrating the chamber from the outside; It consists of a gas injection pipe extended inward and the terminal end of which is located above the wafer loading boat.

In the above-described configuration, the gas injection pipe may be formed in a structure in which the diameter decreases toward the terminal portion. Moreover, the nozzle attached to the lower side of the outer periphery can also be arrange | positioned as a diameter gradually gradually toward the terminal part of a gas injection pipe.

In the present invention, the gas supply pipe may be formed in a straight line or an x-shape or at least one ring shape arranged concentrically across the boat.

In the present invention, since the reaction gas injected through the gas injection tube is uniformly supplied over the entire upper surface of the wafer, thermally unstable reaction products do not exist as in the prior art, thereby improving the processing quality of the wafer and reducing the defect rate. It has advantages.

1 is a conceptual diagram showing the configuration of a conventional high density chemical vapor deposition apparatus.

Fig. 2 is a side sectional view showing the structure of a high density chemical vapor deposition apparatus according to the present invention.

3 is a cross-sectional view of the main nozzle nozzle body of the present invention.

Fig. 4 is a plan view showing another embodiment related to the arrangement of the nozzle tubes shown in Fig. 3.

5 is a plan view showing another embodiment of the nozzle tube;

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

20: chamber 22: wafer

24: boat 26: lifter

28: high frequency electrode 30: quartz cover

32: heater 34: door

36: wafer entrance 38: exhaust

40: gas injection pipe 42: distal end

44 connector 46 nozzle

Preferred embodiments of the present invention described above will be described in detail with reference to FIGS. 2 to 5 as follows.

2 is a side cross-sectional view showing the structure of a high-density chemical vapor deposition apparatus to which the present invention is applied. The chamber 20 has a boat 24 in which a wafer 22 is placed in an inner center thereof. In conjunction with the lifter 26 provided in the outer lower side of the chamber 20, it is lifted up and down a predetermined range.

The upper side of the chamber 20 is covered with a quartz cover 30 having a high frequency electrode 28 arranged on an inner circumferential surface thereof, and a heater 32 is mounted on an outer side thereof to warm the inside of the chamber 20. have.

In addition, at one side of the chamber 20, a wafer entrance 36 is opened and closed by a door 34, and the other part is an exhaust port 38 communicating with an exhaust passage to exhaust the internal air of the chamber 20. ) Is open.

On the other hand, in the chamber 20 of the above-described configuration, a gas injection pipe 40 penetrated from the outside and drawn into one side of the inside is piped, and the distal end portion 42 of the gas injection pipe 40 is interposed through a connection port 44. And extending upward of the boat 24.

The distal end 42 of the gas injection pipe 40 is provided with a nozzle 46 at the lower side. As shown in FIG. 3, the nozzle 46 has a larger diameter toward the end of the distal end 42, so that the gas injected through the distal end 42 is greater and weaker in the end-side nozzle 46. In addition, the nozzles 46 adjacent to the connection port 44 may be injected at a small and strong pressure to induce uniform diffusion of the reaction gas.

The gas injection pipe 42 having such a configuration is not limited to the embodiment shown in FIG. 2, but has a branch pipe 420 arranged in an X-shape at the end of the distal end 42 as shown in FIG. 4. Alternatively, as shown in FIG. 5, one or more large and small ring-shaped branch pipes 440 may be arranged concentrically on the distal end portion 42.

In addition, the distal end portion 42 of the gas injection pipe 40 does not necessarily have to be disposed above the boat 24, but for example, extends along the inner circumferential surface of the chamber 20, but each nozzle 46 is provided on the boat. The outer periphery of (24) may be arranged to be oriented.

When the distal end portion 42 of the gas injection pipe 40 is configured as described above, the diffusion of the reaction gas can proceed more uniformly and quickly.

Next, the process of processing the wafer through the present invention having the above-described configuration will be described. The wafer 22 is charged through the wafer entrance and exit 36 by a suitable conveying means and deposited on the upper surface of the boat 24. Then, the door 34 is closed, so that the chamber 20 is isolated from the outside and the inside of the chamber 20 is evacuated due to the negative pressure applied through the exhaust port 38. In this state, the reaction gas injected into the gas injection tube 40 is injected through each nozzle 46 of the distal end portion 42 and evenly diffused onto the surface of the wafer 22. Subsequently, when the glow discharge starts from the high frequency electrode 28, the reaction gas is decomposed to form a thin film on the surface of the wafer 22. When a thin film is formed on the surface of the wafer 22 with a desired thickness after a predetermined time, the glow discharge through the high frequency electrode 28 is stopped and the processed wafer 22 is taken out from the chamber 20.

By repeating such a process, the wafer 22 in which the thin film was formed can be obtained continuously. In addition, the inside of the chamber 20 is maintained at constant temperature by the heater 32 arrange | positioned outside the quartz cover 30 during the vapor deposition process.

As described above, in the process of forming a thin film on the surface of the wafer, the distal end portion of the gas injection pipe 40 in which the reaction gas injected into the chamber 20 is disposed across the upper portion of the boat 24 ( Since 42 is injected through a plurality of nozzles 46, it is rapidly diffused and supplied to the surface of the wafer 22, thereby making the supply of the reaction gas uniform.

Therefore, the surface of the wafer 22 processed by the apparatus of the present invention remains in a very small amount even if there is no thermally unstable material.

As described above, the present invention extends the gas injection pipe disposed inside the chamber to be disposed across the boat, and has a plurality of nozzles arranged on the outer circumference thereof to uniformly distribute the surface reaction gas of the wafer. This has the effect of eliminating the residual amount of the thermally unstable reaction product which appeared to be a problem, thereby improving the processing quality of the wafer and lowering the defective rate.

Claims (6)

A chamber 20 in which an wafer loading boat 24 is liftable at an inner center thereof and covered upwardly so as to be isolated from outside air by a cover 30; A lifter (26) disposed at an outer lower side of the chamber (20) for raising and lowering the wafer loading boat (24) up and down; A wafer entrance 36 formed at one side of the chamber 20 and opened and closed by a door 34; An exhaust pipe (see 38) communicating with one side of the chamber 20 to provide an exhaust passage of internal air; High density chemical vapor deposition having a gas injection tube 40 extending from the outside through the wall of the chamber 20 and having its distal end 42 positioned above the wafer loading boat 24. Device. The high density chemical vapor deposition apparatus according to claim 1, wherein the distal end portion (42) of the gas injection pipe (40) is larger in diameter toward the end. 3. The high density chemical vapor deposition apparatus according to claim 2, wherein a plurality of nozzles 46, the diameter of which gradually increases toward the end, is arranged below the distal end portion 42. 3. A high density chemical vapor deposition apparatus according to claim 2, characterized in that the distal end (42) is formed in a straight line across the boat (24) above the boat (24). 3. The high density chemical vapor deposition apparatus according to claim 2, wherein the distal end portion (42) is further provided with an X-shaped branch tube (420) at its end to communicate with the distal end portion (42). 3. The high density chemical vapor deposition apparatus according to claim 2, wherein the distal end portion (42) is further provided with at least two ring-shaped branch tubes (440) concentrically arranged so as to communicate with the distal end portion (42).