JP2798044B2 - Single wafer type plasma CVD equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a VD apparatus, and more particularly to a single-plate type plasma CVD apparatus having a heating table on which a semiconductor substrate (hereinafter simply referred to as a wafer) is placed.

[0002]

2. Description of the Related Art A plasma CVD method using a material gas such as TEOS, SiH ₄ or O ₂ is widely used for forming an insulating film. The plasma CVD method includes a wafer type and a batch type. However, in the batch type, it is difficult to control the process parameters of each individual wafer.

FIG. 3 is a schematic sectional view showing an example of a conventional single-wafer plasma CVD apparatus. Conventionally, as shown in FIG. 3, this single-plate type plasma CVD apparatus mounts a single wafer 13 to be processed, which is housed in a chamber 9 and has a flat susceptor fastened to a heater block 6 by bolts 11. 3 and a shower head 12 for dispersing gas to a wafer 13 heated by the heater block 6.

In order to form an insulating film on a wafer using this single-plate type plasma CVD apparatus, first, the bellows 10 are pushed and the wafer 13 is placed on the raised pins 7 with the gate valve 5 opened. Next, the gate valve 5 is closed and the pin 7
Moves down and transfers the wafer 13 to the susceptor 3. Next, material gas is supplied to the shower head 12 from the gas inlet,
Gas is blown onto the wafer 13 from a number of holes in the shower head 12. At the same time, high-frequency power is applied between the susceptor 3 and the shower head 12. As a result, an insulating film is formed on the wafer 13.

After the insulating film is formed, the wafer 13 is taken out of the chamber 9, a cleaning gas is introduced from the shower head 12 into the chamber 9, and high-frequency power is applied between the susceptor 3 and the shower head 12. Then, the film formed on the inner wall surface of the chamber 9 serving as a particle generation source is removed. As described above, conventionally, in the single-wafer plasma CVD apparatus, the growth of the insulating film and the cleaning are alternately repeated.

[0006]

In the conventional single-wafer plasma CVD apparatus described above, the susceptor is exposed to a plasma atmosphere, so that the surface of the susceptor is roughened to generate particles and change the quality of a film to be formed. Therefore, conventionally,
This has been dealt with by periodically replacing this susceptor.

[0007] However, mounting a thin susceptor on a heater block requires experience.
A gap is formed by partially tightening the bolt, or a gap is formed due to irregularities on the surface of the susceptor or the heater block, and the amount of heat conduction and the amount of electric conduction change. As a result, there is a problem that the density of a film formed by the plasma CVD apparatus changes, and a serious defect in quality occurs when the moisture resistance, insulation and etching rate of the film change.

Further, even if the susceptor is fixed to the heater block with a uniform fastening force, the process gas enters a small gap at the end, and an insulating film is formed on the lower surface of the susceptor.
In this state, if the susceptor is replaced with a new susceptor having an uneven surface on the lower surface, the insulating film is sandwiched in a part of the contact between the heater block and the susceptor. As a result, the same problem as described above occurs.

On the other hand, as an example of solving this problem, a plasma C for making the contact between the heater block and the susceptor uniform is provided.
A VD device is disclosed in Japanese Patent Application Laid-Open No. 01-154515. In this method, a metal powder having a high thermal conductivity is interposed between the susceptor and the heating means to increase a contact area and increase a heat conduction amount. However, since it is in powder form, handling is difficult, and it is unavoidable that it scatters in the chamber, accumulates at the bottom of the chamber, and contaminates the wafer. Also,
Since it is in a powder form, the heat transfer coefficient and the electric conductivity are lower than those of a solid material, so that it cannot be said that this method is necessarily an advantageous method.

[0010] Accordingly, an object of the present invention is to provide a single-plate plasma C capable of making the contact between the susceptor and the heater block uniform and performing stable heat and electric conduction even when the susceptor is replaced.
It is to provide a VD device.

[0011]

SUMMARY OF THE INVENTION A feature of the present invention is that a flat susceptor is placed in a chamber for mounting one of the semiconductor substrates to be processed, and a heater for heating the semiconductor substrate via the susceptor. Single-wafer plasma C comprising a block and a shower head for dispersing a gas on the semiconductor substrate
In a VD apparatus, a single-wafer plasma CVD apparatus having a heat conductive plate which is sandwiched and fastened between the susceptor and the heater block and has a metal layer formed mainly by adding a lead material to a copper material on a copper substrate surface It is. Further, it is desirable that the lead material contained in the metal layer is 25 to 35%.

[0012]

Next, the present invention will be described with reference to the drawings.

FIGS. 1A and 1B are a schematic cross-sectional view showing a single-wafer plasma CVD apparatus according to an embodiment of the present invention, and FIG.
It is. As shown in FIG. 1, this single-plate type plasma CVD apparatus is sandwiched between a susceptor 3 and a heater block 6 and is fastened with bolts 11. That is, the heat conductive plate 1 on which the added metal layer 2 is formed is provided.

In addition, a shower head 12 provided on the upper part of the chamber 9, pins 7 for pushing up a wafer 13 provided below the heater block 6, and a bellows which gives repulsive force to the pins 7 to draw the pins 7 from the surface of the susceptor 3. 10 is provided in the same manner as in the conventional example.

As shown in FIG. 1B, the heat conductive plate 1
It is composed of a substrate 1a made of copper as a core and a metal layer 2 of soft high lead bronze formed on the surface of the substrate 1a. The metal layer 2 is made of copper having high thermal conductivity and electric conductivity as a main material, and is added with lead for softening. The metal layer 2 is obtained by immersing the substrate 1a in a high-lead bronze solution and performing hot-dip plating.

In order to determine the ratio of copper to lead in the metal layer 2, in order to make the thermal conductivity and electric conductivity almost the same as those of copper and to make them soft enough to catch the nails,
Copper is used as a main material, and lead is added to the main material to increase the content of lead material. If lead is contained in the range of 25 to 35%, desired thermal conductivity and softness (Brinell hardness of 30 to 35%) are obtained. About 40) was obtained. A copper substrate 1 of about 1 mm
The metal layer 2 having a thickness of about 0.7 mm with respect to a was formed.

FIG. 2 is a view for explaining a method of attaching the susceptor to the heater block with the heat conducting plate of FIG. 1 interposed therebetween. To attach the susceptor 3 to the heater block 6 via the heat conductive plate 1 having a soft metal layer on the surface, first,
As shown in FIG. 2, the infrared camera 1 is located above the susceptor 3.
5 is arranged, and it is observed by the display 14 that the amount of infrared rays emitted from the susceptor 3 is changed by tightening the bolt 11. Then, while adjusting the tightening of the plurality of bolts 11 respectively, the temperature distribution image displayed on the display 11 is made uniform.

Of course, the temperature of the heater block 6 may be a low temperature that does not hinder the work of tightening the bolts 11. By the way, when the susceptor 3 which was judged to be in uniform contact after the tightening adjustment of the bolt 11 was removed, irregularities were generated on the surface of the heat conductive plate 1. This is illustrated in FIG.
It can be said that the surface of the heat conductive plate 1 is deformed according to the irregularities on the surfaces of the susceptor 3 and the heater block 6 as shown in the circles.

Further, the heat conductive plate 1 having once been used with a rough surface can be easily regenerated by placing it in a high-temperature furnace and reflowing the surface in order to regenerate the surface evenly. 1 can be used multiple times. Further, there is an advantage that the cost increase due to the heat conductive plate 1 is less than the mounting adjustment cost performed only by the conventional experience.

[0020]

As described above, according to the present invention, the susceptor is fastened to the heater block with a plurality of bolts via the heat conductive plate having the soft surface layer, and the heat is applied according to the rear surface of the susceptor and the surface condition of the heater block. The surface layer of the conductive plate follows and deforms to make the contact uniform, so that even if the susceptor is replaced, stable thermal and electrical conductivity can be obtained.
There is an effect that a stable etching and a high-quality film can always be formed.

[Brief description of the drawings]

FIG. 1A is a schematic cross-sectional view showing a single-wafer plasma CVD apparatus according to an embodiment of the present invention, and FIG.

FIG. 2 is a view for explaining a method of attaching a susceptor with the heat conducting plate of FIG. 1 interposed between heater blocks.

FIG. 3 is a schematic sectional view showing an example of a conventional single-wafer plasma CVD apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal conductive plate 1a Substrate 2 Metal layer 3 Susceptor 5 Gate valve 6 Heater block 7 Pin 9 Chamber 10 Bellow 11 Volt 12 Shower head 13 Wafer 14 Display 15 Infrared camera

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/31 H01L 21/68 N 21/68 21/302 B

Claims (2)

(57) [Claims] 1. A flat susceptor which is placed in a chamber and on which one semiconductor substrate to be processed is placed, a heater block which heats the semiconductor substrate via the susceptor, and a gas is dispersed in the semiconductor substrate. In a single-wafer plasma CVD apparatus provided with a shower head, a heat conduction between a susceptor and a heater block is sandwiched and fastened and a metal layer mainly doped with a lead material made of a copper material is formed on the surface of a copper substrate. A single-wafer plasma CVD apparatus comprising a plate. 2. The single-type plasma CVD apparatus according to claim 1, wherein the amount of lead added to the metal layer is 25 to 35%.