JPS61152024A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make it feasible to substantially laminate a metal or metallic compound on a gate insulating film on an extremely thin semiconductor film coming into close contact therewith by a method wherein, within an insulating gate type field effect semiconductor device, a semiconductor film and a conductor thereon are formed in the same reactor without exposing them to atmosphere. CONSTITUTION:A P-type channel region 10 and a gate electrode 6 made of metallic tungsten are formed on a substrate 1. A silicon oxide film 3 300Angstrom thick is formed and then a semiconductor film 4 30-300Angstrom thick is formed by photochemical reactor on the film 3. Later metallic tungsten is formed by plasma CVD process by vacuumizing and leading tungsten fluoride and hydrogen to a reactor without exposing the tungsten to atmosphere. After forming a conductor 5 for gate electrode, a gate electrode 6 is formed by photolithography. Within said processes, the gate electrode 6 and a lead extending therefrom are not subject to any exfoliation phenomenon even if the pattern width thereof is extremely narrow e.g. 1mum.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a method for manufacturing a gate electrode of an insulated gate field effect semiconductor device (referred to as IGF) and an electrode of a capacitor. This invention relates to a method in which a semiconductor film is formed by a CVD (vapor phase reaction) method using a photochemical reaction, and a metal or a metal compound is laminated on the semiconductor film without exposing the surface of the film to the atmosphere.

4. Prior Art As a method for manufacturing a gate electrode of an IGF, a method is known in which a semiconductor film and a conductor film thereon are each manufactured using different reaction methods and different reaction vessels. In particular, regarding silicon semiconductors, a two-layer structure is formed on a gate insulating layer made by a hydrochloric acid oxidation method, consisting of a semiconductor, especially a silicon semiconductor, and a conductor, such as molybdenum, on top of this semiconductor to promote electrical conductivity. However, it has been impossible to uniformly fabricate this silicon semiconductor to a thickness of 300 Å or less using conventional process technologies such as low-pressure vapor phase method and plasma vapor phase method. 3
It has a thickness of 1,000 to 3,000 and a metal film on it is 1,000 to 3,000.
It was formed to a thickness of 0,000 people. At such a thickness, the effects of adsorbed oxygen and water at the interface between the semiconductor and the conductor did not pose a particular problem.

However, when this semiconductor film was made thinner by 30 to 300 people, the semiconductor itself was oxidized by the adsorbed substances, and the metal came into substantially direct contact with the gate insulating film, causing a decrease in reliability.

For this reason, in the microchannel old 5-LSI with a size of 1 μm or less, a short circuit between the gate electrode and the substrate occurred, causing a decrease in yield.

Means for Solving Problem 1 In order to solve these problems, the present invention uses photo-CVD to form a stable semiconductor film that does not cause any damage to the underlying silicon oxide film, and then subsequently coats this surface. A two-layer gate electrode is constructed by forming a metal or a metal compound without exposing it to the atmosphere. This process eliminates the reaction between the semiconductor of the gate electrode and adsorbed substances such as water and oxygen, and allows the metal or metal compound to be substantially laminated on the gate insulating film with good adhesion to an extremely thin semiconductor film, especially a silicon semiconductor film. It has become possible.

r effect 1 This semiconductor film, silicon (amorphous or polycrystalline)', can be made by photo-CVD to
It is possible to form an extremely thin and uniform film with zero damage to the underlying insulating film.And when forming a metal or metal compound on top of this, it prevents the adsorption of oxides on the surface of the semiconductor. As a result, the presence of metal oxides and hydrides between the gate insulator and the high melting point metal for the gate electrode also prevents the catalytic action caused by the metal coming into substantial, especially direct contact with the gate insulator. In this way, a local reaction near the lattice-electrode interface (including the semiconductor-metal interface in the electrode) partially insulates and partially destroys the semiconductor film. For the first time, it has become possible to prevent the reaction between metals and silicon oxide.

In the present invention, the semiconductor film and the conductor thereon are formed in the same reaction furnace without exposing the semiconductor film to the atmosphere.

That is, after first forming a semiconductor film by photo-CVD, the inside of the reactor is evacuated, and then a reactive gas for the conductor is introduced.
This is one reactor method in which layers are formed using the CVD method. However, there is a method in which each film is formed in two reactors connected to each other, that is, the semiconductor film is first formed by photo-CVD, and after evacuation, the gate valve is opened and the substrate is transferred to the adjacent reactor. It is also possible to adopt a multi-chamber method in which the conductive film is laminated and formed without exposing it to the atmosphere after the gate valve is closed.

Example 1 FIG. 1 shows a longitudinal cross-sectional view of the IGF of the present invention.

That is, the IGP consists of a substrate (1), a field insulator (2),
Gate insulator (5) made of silicon oxide film (3), gate electrode (6) made of semiconductor film (4) and metal or metal compound (5), source (7), drain (8), channel cut (9) ), and a channel forming region (10).

The drawing shows an N-channel IGF with P(1) on the substrate (1).
0), and the channel length is 1.5μ.
, the channel width was 10μ. The gate electrode was made of tungsten metal. The silicon oxide film (3) has a thickness of 300 nm and is a thermal oxide film formed by a hydrochloric acid oxidation method.

Example 2 details of the method for manufacturing the semiconductor film thereon
As shown in Figure 2, the film was formed to a thickness of 30 to 300 people, for example, 100 people, by photochemical reaction. After this, vacuum the
Introducing tungsten fluoride (wph) and hydrogen into the reactor, adding electrical energy to 1'h+3Hg W
+ 6HF to plasma C tungsten metal
It was formed by the VD method.

This gate electrode conductor is WF6 + 2SiHa-WSiz +68F+H2
A metal compound may also be formed as a metal compound.

After forming such a conductor for the gate electrode, a gate electrode was formed using a known photolithography technique. Furthermore, a source (7) is formed by ion implantation.

Impurities were implanted into the drain (8), and photoannealing was performed. In this way, the gate, source, and drain were fabricated using the self-line method, but during these steps, the peeling phenomenon occurred on the gate electrode and the leads extending from it because the pattern width was 1.
I could not see it even though it was extremely narrow.

In such an IGF, Mo, which is a heat-resistant metal, does not form a silicon semiconductor film, that is, directly coats silicon oxide.

TitII4. l'1Stz+ Mo5tz, Ti5i
Compared to the case where z or the like is formed, it was possible to substantially provide the electrode conductor with excellent adhesion to the base insulating film. As a result, v th was constant at 0.7 V + 0.2 V, and the amount of drift was 0.0 in the BT (bias/temperature) test (3 hours) in an electric field of 150 °C I XIO' V/c11. I could only see 2v or less.

Example 2 Hereinafter, based on the drawing shown in FIG. 2, details of the production of a Si film by the photo-CVD method of the present invention and the method of subsequently forming a conductor on a semiconductor without exposing it to the atmosphere will be described.

In FIG. 2, a silicon substrate (1) having a surface to be formed
is held in a holder (1') and is provided in close proximity to a halogen heater (13) (the top surface of which is water-cooled (31)) in the reaction chamber (12). The reaction chamber (12), the light source chamber (35) in which the ultraviolet light source was disposed, and the heating chamber (30) in which the heater (13) was disposed were maintained at approximately the same degree of vacuum of 10 torr or less. . For this purpose, a gas (hydrogen, argon or helium) that does not interfere with the reaction (28
) to (36) and exhaust from Z or (36'').Also, the light source chamber (35) and reaction chamber (12) are separated by the quartz window (40), which is a light-transmitting shielding plate. There is a nozzle (3) on the upper side of this window (40).
4) was provided to guide the reactive gas (33) inside. This nozzle also has a mesh (34°) and constitutes an electrode for plasma CVD.

This nozzle (34) uses a plasma vapor phase method and a window (
40) High frequency power source (15) (frequency 13.
56MH2).

A heater (29) was provided to prevent reactive gas from entering the light source chamber due to backflow when the light source chamber was evacuated.

As a result, components of the reactive gas that become solid after decomposition were removed, and only the gas was introduced.

Regarding movement, a load-lock system was used to prevent pressure differences from occurring. First, the board (1) is placed in the preliminary room (14).
After inserting and arranging the holder (1') and evacuating, the gate valve (16) was opened and the reactor was transferred to the reaction chamber (12). Also, with the gate valve (16) closed, the reaction chamber (12)
, the preliminary rooms (14) were partitioned off from each other.

The doping system (37) includes pulp (22), flowmeter (
21), and %IF& is from (23), hydrogen is (2
4), (26). Si, P6 or 5
izH6 from (25) and etching gas NF.
3 was supplied from (27).

The pressure in the reaction chamber is controlled by a control valve (17).

A turbo molecular pump (Osaka Vacuum P
G550) (18), rotary pump (1
9) and then evacuated.

The exhaust system (38) is connected to the preliminary chamber (14) by the cock (20).
When vacuuming the chamber, open that side and open the reaction chamber (12
) side is closed. Furthermore, when evacuating the reaction chamber, the reaction chamber was opened and the preliminary chamber side was closed.

The substrate was thus inserted into the reaction chamber as shown.

The degree of vacuum in this reaction chamber is 10-? torr or less. Thereafter, nitrogen was introduced from (28), and SigHh or SigFh was introduced from (25) together with a and (26) into the reaction chamber to form a silicon semiconductor film.

The light source for the reaction was a low-pressure mercury lamp (34), water-cooled (31°).
has been established. The ultraviolet light source is a low-pressure mercury lamp (185n+m
.

Emit light with a wavelength of 254n-, emission length 40cm, irradiation intensity 15mW/c■2. Lamp power: 40-) Number of lamps: 16.

This ultraviolet light passes through quartz (40), which is a transparent shielding plate, and irradiates the surface of the substrate (1) in the reaction chamber (12) to be formed.

The heater (13) was a "deposition up" type heater located above the reaction chamber, and heated the substrate to 300°C.

In this way, a Si film with a thickness of 100 layers could be formed in about 5 minutes. Thereafter, (25) and (26) were closed, and the reaction chamber (2) was evacuated to 10-' torr using a turbo pump (1B). Further, the ridge (23) was flowed together with hydrogen (24). In addition, the pressure Q, l
13.56 Ml (z(15) was applied at torr,
A conductor was formed on a silicon semiconductor film without exposing it to the atmosphere.

In the case of the drawing, the effective area to be formed is 30cw x 30ca
*, and five boards (1) with a diameter of 5 inches are placed in a holder (1).
(a)).

When the conductor film is WSig, WFh (23) and 5il
t(25).

Example 3 Preparation of Si film and molybdenum film 5ilF,
Alternatively, 5izHa was connected to (25) and fed at 8 cc/min. (26) supplied hydrogen at a rate of 30 cc/min.

Then, these were photodecomposed by receiving 184 rv+ light from the ultraviolet light source (32) without using mercury, and it was possible to form a Si film to a thickness of approximately 100 nm on the surface of the substrate (1). . That is, by forming the silicon film on the window (40), it was possible to form the silicon film to a thickness of 30 to 300 nm, which is the thickness required to block ultraviolet light.

A molybdenum film was formed on the polycrystalline or amorphous silicon film. That is, from (23), molybdenum chloride is
Further, hydrogen was supplied from (24), and a metal molybdenum film was formed on the upper surface by photo-plasma CVD or plasma CVD in which both photo-CVD and photo-plasma reactions were performed simultaneously. In this way, a semiconductor and a metal film were formed on the gate insulating film as a conductor for a gate electrode.

Plasma etching in the reactor after the reaction was performed using NF3 to take out the substrate and then applying 80-high frequency energy from (15).

r effect J As is clear from the above description, the present invention is a gate electrode formed by forming a semiconductor film using a photo-CVO method, and subsequently forming a conductor thereon.

As a result, the high melting point metal has excellent adhesion, and the voltage applied to the gate electrode can be effectively applied to the channel forming region (1) of the semiconductor (1).
0) (Fig. 1), and a depletion layer could be formed.

In the present invention, optical C
The VD method was used. However, the film formation temperature at that time was 20
At low temperatures of 0 to 350 degrees Celsius (at high temperatures of 500 to 900 degrees Celsius (at pressures of 0.1 to 3 degrees Celsius) to prevent hydrogen from remaining in the film).
torr), or silicon (
It goes without saying that the germanium film may be formed using G13H++GezFh+GeFa.

As is clear from the above description, when forming a film on a large-area substrate, the present invention prevents the formation of an unnecessary reaction-generated film on the window, which requires 30 to 300 people before the film formation is interrupted. This extremely thin film was fabricated as a profking layer on the metal insulator below the gate electrode. For this reason, in the apparatus shown in Figure 2, after this film formation is completed and the substrate is taken out, the reaction chamber is evacuated and unnecessary materials on the window are completely removed by plasma etching, and the next new surface is coated. It is extremely important to carry out the formation.

Furthermore, in addition to forming a semiconductor film using this photo-CVD method,
As a pre-process, a silicon nitride film or aluminum nitride film is deposited on the silicon oxide film as part of the gate insulating film by photoCVD.
It may be formed by method D.

In the present invention, the electrode material is silicon to which intrinsic or impurities have been added, as well as silicon that is not exposed to the atmosphere (laminated semiconductors, silicon-based compounds (MO5iz), etc.).
+WSiz, Ti5it) or Mo, W, Ti, ^
l.

Indicates the metal of Si. However, other conductors may also be used.

Further, it is effective to use the method of the present invention as an electrode of a capacitor such as 17r/cal1.

Regarding multilayer films, the semiconductor film is first formed in a first reactor, and then the surface of the first semiconductor film is exposed to the atmosphere by stacking layers on top of it using an adjacent reactor connected to a conductor. Forming the second conductive film in a layered manner is even more excellent in improving productivity.

In the experimental example described above, a low-pressure mercury lamp was not used as the light source for optical CVD (an excimer laser (wavelength: 100 to 400 nm) was used as the light source.
m) It goes without saying that an argon laser, a nitrogen laser, etc. may also be used.

[Brief explanation of the drawing]

FIG. 1 shows an insulated gate field effect semiconductor device of the present invention. FIG. 2 shows the CVO device of the present invention.

Claims (1)

[Claims] 1. Forming a semiconductor film on an insulating film or dielectric as a film for part or all of a gate electrode or a capacitor electrode in an insulated gate field effect semiconductor device;
A method for manufacturing a semiconductor device, comprising the step of forming a metal film or a metal compound film on the film without exposing the film to the atmosphere after the step. 2. In claim 1, the semiconductor film is formed by a photo-vapor phase reaction method, and the conductor is formed by a photo-plasma vapor phase reaction that performs a plasma vapor phase reaction, a photo vapor phase reaction, or both simultaneously. A semiconductor device manufacturing method characterized by: