JPH0243731A - Vapor growth device for semiconductor - Google Patents

Abstract

PURPOSE:To contrive the improvement of the discharge efficiency of plasma, the increase of the growth rate and the improvement of film thickness uniformity of a chemical vapor phase growth film by a method wherein the side surface of a semiconductor substrate is brought into contact to a conductive film which is formed on a holder pin, which is formed on a susceptor, and shows a high conductivity. CONSTITUTION:Reaction gas is filled, a pair of parallel-plate electrodes 12 are arranged in the interior of a reaction container 1 communicated with an evacuator and a film is deposited on each semiconductor substrate 7 to be treated which is fixed on a susceptor 8, which is connected to at least one of the electrodes 12 and consists of a conductive substance, through each holder pin 14 which is formed on the susceptor 8. In such a vapor growth device for semiconductor, the side surface 15 of said substrate 7 is brought into contact to other conductive film 17 which is formed on said holder pin 14 and shows a high conductivity. For example, a gradient 16 to conform to that of the side surface 15 of a semiconductor substrate 7 to be treated is formed on the periphery of a holder pin 14, which is mounted on a susceptor 8 made of carbon and is similarly made of carbon, and moreover, Al or an Al alloy is deposited on the surface of the holder pin by a deposition method or a sputtering method to form a film 17.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a vapor phase acid deposition apparatus for semiconductors, and particularly relates to a plasma cVD (Chemical Vapor Depth
position) Regarding the shape and material of a susceptor for a semiconductor substrate in an apparatus.

(Prior art) The development of semiconductor devices has largely depended on the development of manufacturing equipment, and one example of this is chemical vapor deposition equipment, especially plasma CVD equipment, which can deposit insulating layers on semiconductor substrates at low temperatures. The outline will be explained with reference to FIG.

First, it should be noted that although this figure shows a horizontal type device, the present invention is not limited thereto.

A gas cabinet 52 is connected to one end 51 of the prepared reaction vessel 50, and a pressure reducing device such as a Roots blower 54 and a rotary pump 55 is connected to the other end 53 in an airtight manner and used as an exhaust port (not shown). On the other hand, a heater 56 and a temperature controller 57 connected to the heater 56 are installed on the outside of the reaction vessel 50 so that the internal temperature can be controlled to about 350 to 400°C. At least one of the semiconductor substrates to be processed 59...
By electrically connecting the susceptor 60 provided with the semiconductors to be processed 59 . . .

This parallel plate electrode 58 generates plasma in the reaction vessel 50 by applying high frequency power by an RF feedthrough 61 derived from a high frequency oscillator 65 shown in FIG. The dregs deposit a predetermined film on the semiconductor substrates 59 to be processed, which are generated by a chemical reaction using this plasma.

To cause this chemical reaction, the roots blower 54 and rotary pump 55 are operated to exhaust the pressure inside the reaction vessel 50 to about 10-3 Torr, and then S! H4, N1-13. This is done while introducing a gas such as N20.

By the way, in order to attach the semiconductor substrate 59 to be processed to the susceptor 60 made of carbon, the steps shown in FIGS.
A holder pin 62 is used as shown in the figure. On the other hand, the reaction vessel 50 has a reaction gas inlet at one end 51 and a reaction gas inlet at the other end 51.
As mentioned above, the exhaust port communicating with the pressure reducing device is formed in 3, and a flow path toward the exhaust port is created for the reaction scum to be introduced.

The susceptor 60 has a flat surface 63 on which the semiconductor substrate 59 to be processed is placed, and since this is erected in the reaction vessel 50 parallel to the flow path, the semiconductor substrate 59 to be processed can be placed on the susceptor 60.
As shown in the figure, 9 surfaces are also arranged along the flow path. In this case, the semiconductor substrate 59 to be processed is pressed and fixed by a pair of holder pins 62, 62 installed below the susceptor 60, as shown in FIG. A cross-sectional view of the five semiconductor substrates to be processed fixed in this way is shown in FIG. 5, which is obtained by cutting FIG. 4 along the line A-.

4 shows the surface of the semiconductor substrate 59 to be processed arranged along the flow path, and FIG. 5 shows the arrangement of the susceptors 60 arranged in the reaction vessel 50. There is.

That is, in the susceptor 6 () installed in the reaction vessel 10, 50 5ON1 and 100 4-inch semiconductor substrates to be processed are arranged in a row as shown in FIG. 5 using the above method.
In addition, a predetermined chemical vapor deposition treatment is performed with the surface thereof placed along the flow path of the reaction scum.

Incidentally, the side surface 64 of the semiconductor substrate 59 to be processed is sloped because a bevel is formed to improve the withstand voltage of the device, whereas the holder pin 62 to be held is configured with a vertical surface. Because of this, there is a gap between both sides.

Further, an insulating layer or PEP (Photo Engraving) that adheres during the manufacturing process of the semiconductor substrate 60 to be processed is added.
A resist film used in the (gprocess) process inevitably adheres to the side surface 64.

On the other hand, recently, dust countermeasures have been attracting attention as the degree of integration has improved, and in order to avoid the effect on subsequent processes due to peeling of the resist layer coated in the PEP process, cleaning methods are being widely adopted. That is, after the resist coating step 5 of the PUP step, there is a back-rinsing step in which thinner is sprayed to remove the resist that has wrapped around the back and side surfaces of the semiconductor substrate to be processed. However, it is quite difficult to completely peel off the (=J deposited resist) on the back surface of the processed semiconductor substrate even in just two steps, and it is also difficult to make the degree of peeling constant.

FIG. 7 shows a cross-sectional view of a semiconductor substrate to be processed that has not undergone this back-rinsing step, and FIG. 8 shows a cross-sectional view of the semiconductor substrate that has undergone this back-rinsing step.

(Problem to be Solved by the Invention) A semiconductor substrate to be processed is coated with various insulating layers necessary for semiconductor elements. When generating,
It was placed on a susceptor. This plasma nitride film usually wraps around and adheres to the backside and side surfaces of the semiconductor substrate to be processed. The Al 1 or 1 alloy to be coated also adheres to the side surfaces of the semiconductor substrate to be processed.

On the other hand, the susceptor is made of carbon, which has excellent conductivity.
The holder pin is also made of carbon.

Moreover, when a large number of semiconductor substrates are subjected to plasma CVD or chemical vapor deposition at the same time, the rate at which the film wraps around the back surface of the substrates is not constant, and the amount of hanging material attached to the side surfaces is also not constant. Furthermore, even if a back-rinsing process is performed, the material that has gone around to the back side will not be completely peeled off, and the degree of peeling will not be constant, so the film thickness will vary by H3 on each side of many semiconductor substrates to be processed. Differences occurred in uniformity and growth rate.

That is, an insulating layer is formed on the back surface of the semiconductor substrate to be processed, and an A layer is formed on the side surface of the semiconductor substrate to be processed.
If the l1 or hel alloy is deposited, a semiconductor substrate to be processed having a relatively high electrical resistance is placed on a relevator having a very low electrical resistance.

For this reason, the plasma discharge efficiency deteriorates, and the growth rate decreases and the in-plane crotch thickness uniformity deteriorates due to the influence of the non-uniform backside insulating layer.

This film thickness uniformity is determined by measuring the film thickness at five locations including four symmetrical peripheral parts of the semiconductor substrate, that is, positions 5 mm apart, and the central part thereof, on which a so-called orientation flat is formed.

Then, evaluate the in-plane crotch thickness uniformity as (highest value of 5-point measurement) - (minimum 1 shift of 5-point measurement) / (2x average value of 5-point measurement) · In-plane membrane 17 unevenness (±%) It was used as a standard.

The present invention was made under these circumstances, and in particular,
The purpose is to improve the plasma discharge efficiency and the growth rate and film thickness uniformity of chemical vapor deposition films.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a pair of parallel plate electrodes arranged in a reaction vessel filled with a reaction gas and communicated with a pressure reducing device, and a conductive electrode connected to at least one of the parallel plate electrodes. In a semiconductor vapor phase growth apparatus in which a film is deposited on a semiconductor substrate to be processed that is fixed via a holder pin formed on a receptor made of a substance, the semiconductor is deposited on another conductive film that is formed on the holder pin and exhibits higher conductivity. The feature is that it makes contact with the side of the board.

(Function) The carbon t-naceptor on which the semiconductor substrate to be processed is placed has
The holder pins are made of the same material, and if they are made of a highly conductive material, i.e., i or he-1 alloy, the difference with the base material will adversely affect film thickness uniformity and plasma discharge efficiency. Therefore, it cannot be adopted.

Under these circumstances, in the present invention, by coating the hold pin with another conductive film such as 81 or 1 alloy, the application state of high frequency voltage can be adjusted to the side and back surfaces of the semiconductor substrate to be processed. are in the same 4th form.

That is, regardless of the presence or absence of a back-rinsing process, another highly conductive film is brought into contact with the carbon constituting the susceptor, and furthermore, silicon, which is the material of the semiconductor substrate, is brought into contact with the high-frequency The voltage application conditions are the same.

It should be noted that as other materials for the conductive film, high melting point metals such as 1 and No, which have higher conductivity than 1 and A42 alloy, can also be used.

(Embodiment) An embodiment of the present invention will be described with reference to FIGS. 1 to 3.

That is, since the reaction vessel 1 shown in FIG. 1 is used with the reaction scum introduced therein and the pressure reduced to about 10-3 Torr, it is natural that it should be formed airtight. A structure is formed at one end 2 of the reaction vessel 1 so that a reaction gas can be introduced and an airtight state can be maintained. Furthermore, since an exhaust port (not shown) for discharging the introduced reaction gas is installed at the other end 3, a flow path for the reaction gas directed thereto is formed.

This reaction dregs is sent from dregs cabinet 4 to S! t-14
, Nl-13, N20, etc. are introduced and used (1!2
Da 3 connects the Roots blower 5 and rotary pump 6 in an airtight state to reduce the pressure inside the reaction vessel 1 to 10"3.
Chemical vapor deposition is performed on the surface of the semiconductor substrate 6 to be processed, with a thickness of approximately 100 nm.

In order to place the semiconductor substrates 7 to be processed in the reaction vessel 1, a carbon susceptor 8 is used, and as shown in FIG. The back side of the semiconductor substrate 6 to be processed is placed.

The susceptor 7 is installed in the reaction vessel 1 by a method in which the flat surface 9 is provided along the flow path of the reaction gas. and is arranged in parallel to the substrate to prepare for chemical vapor deposition using plasma under reduced pressure.

In order to cause this plasma reaction, a heater 10 and a temperature controller 1 connected to the heater 10 are installed on the outside of the reaction vessel 1.
1 is installed so that the internal temperature can be controlled to about 350 to 400'C, and a parallel plate electrode 12 is provided inside this.

A susceptor 8 is attached to at least one of the parallel plate electrodes 12.
are electrically connected to perform chemical vapor deposition on the semiconductor substrate 7 to be processed. Furthermore, the parallel plate electrode 12 is connected to an RF feedthrough 1 derived from a high frequency oscillator (not shown).
3, high frequency power is applied to form plasma in the reaction vessel 1.

In this way, the semiconductor substrate 7 to be processed placed in the reaction container 1
... are installed on the flat surface 9 of the susceptor 8, but in order to fix them, the 2
holder pins 14, 14 (FIG. 2) are used. A holder for the semiconductor substrate 7 to be processed is formed on the top of this. Further, on the side surface 15 of the semiconductor substrate 7 to be processed, a bevel or gradient of a mixed type of positive and negative pressure is formed to increase the withstand voltage. The process of removing the resist layer that has wrapped around the back surface is the same as in the prior art. Further, on the side surface 15 of the semiconductor substrate 7 to be processed where the slope is formed, wiring +Afl or Al1-3i- which is essential for the semiconductor element is provided.
In some cases, the AJ2 alloy such as Cu or Afl-Cu is coated, and in other cases, the resist layer is also removed by the back-rinsing process and this wiring material is not attached. Incidentally, a gradient device 6 is formed around the holder pin 14.14 attached to the susceptor 7 to match the gradient of the side surface 15 of the semiconductor substrate 7 to be processed. A coating 17 is formed by depositing Al1 or Al1 alloy by a vapor deposition method or a Yasbuttering method.

The metal to be deposited is Al2 or Aβ5i-C1l, which has excellent conductivity due to carbon constituting the susceptor 8.
b L/ <L; J, AE −CIJ 'j 17)
ANQ Gold is preferable, and as mentioned above, high melting point metals such as W and No can also be used. This is shown in the cross-sectional view of Figure 2.

As is clear from FIG. 2, the chemical vapor deposition apparatus according to the present invention, that is, the vapor phase growth apparatus, uses a susceptor with a special (1°4 structure), and a beveled surface is installed on the side surface. A chemical vapor deposition layer can be reliably and stably deposited on a semiconductor substrate to be processed.

This is because the holder pin 14 is coated with a highly conductive film 17 that has higher conductivity than the carbon that makes up the susceptor 8, so it can be used reliably regardless of the presence or absence of an insulating layer attached to the semiconductor substrate 7 to be processed. The formation of a plasma and thus the deposition of a stable chemical vapor deposition layer became possible.

[Effect of the invention 1] A semiconductor substrate to be processed that is fixed to the Zahibbuta and not subjected to the back-rinsing process, a semiconductor substrate to be processed that has been subjected to the back-rinsing process, and a semiconductor substrate to be processed that has been fixed to the Zahibuta, and a semiconductor substrate to be processed that has been subjected to the back-rinsing process. FIG. 3 shows the growth rate and in-plane thickness uniformity of a semiconductor substrate to be processed using the susceptor and holder pin according to the present invention.

As is clear from this figure, Lee has a growth rate of 300 people/
In contrast, in the mouth, the growth rate decreased to 250 people/min, and the in-plane film thickness uniformity significantly increased to an average of ±15%. It's getting worse.

On the other hand, sea urchin ha has a growth rate almost the same as sea urchin 30.
The rate increased to 0 people/min, and the in-plane film thickness uniformity was ±4%, which is the same result as A.

In this way, even for semiconductor substrates to be processed whose periphery has been cut by a back-rinsing process, by using the vapor phase growth apparatus according to the present invention, it is possible to improve film thickness uniformity without reducing the growth rate or impairing productivity. For example, a silicon nitride film can be produced without deterioration of the quality of the product, and of course other films such as silicon dioxide can also be produced.

[Brief explanation of the drawing]

1 to 3 are diagrams for explaining one embodiment of the present invention. FIG. 1 is a cross-sectional view showing an outline of a reaction vessel, and FIG.
FIG. 3 is a cross-sectional view showing the main parts of the reaction vessel, FIG. 3 is a diagram clarifying its characteristics, FIG. 6 and 7 are cross-sectional views of a susceptor to which a semiconductor substrate to be processed is attached. 1... Reaction container semiconductor substrate to be processed 8... Susceptor 14: Holder pin 15... Side surface 17 of semiconductor substrate to be processed... Conductive coating

Claims (1)

[Claims] A semiconductor substrate to be processed, in which a pair of parallel plate electrodes are arranged in a reaction vessel filled with a reaction gas and communicated with a pressure reducing device, and fixed via a holder pin formed on a susceptor made of a conductive material connected to at least one of the parallel plate electrodes. In a semiconductor vapor phase growth apparatus for depositing a film on a semiconductor substrate, the side surface of the semiconductor substrate is brought into contact with another conductive film that is formed on the holder pin and exhibits higher conductivity. Device