JP2995776B2 - Semiconductor device manufacturing method and ECRCVD apparatus used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A. Industrial application fields B. Summary of the invention C. Background art [Fig. 7] D. Problems to be solved by the invention [Figs. 8 and 9] E. Means for solving the problems F. Function G. Embodiment [FIGS. 1 to 6] a. First Embodiment [FIGS. 1 to 3] a-1. One example of an ECRCVD apparatus [FIG. 2] a-2. . Another example of ECRCVD apparatus [Fig. 3] b. Second embodiment [Figs. 4 to 6] H. Effects of the invention (A. Industrial application field) The present invention relates to a method of manufacturing a semiconductor device. And ECRCVD used for it
The present invention relates to a method of manufacturing a semiconductor device, in particular, a trench formed in a surface portion of a substrate is buried with an insulating film formed by bias ECRCVD, and an insulating film generated outside the trench at that time is etched back horizontally.

(B. Summary of the Invention) In the present invention, in order to improve the throughput, a horizontal return etching of the insulating film outside the trench is performed by RIE following the bias ECRCVD for burying the insulating film. In order to perform RIE continuously, a gate valve that opens and closes a plasma extraction window is provided in the ECRCVD apparatus, and a high-frequency voltage for generating plasma can be applied between the gate valve and a support that supports the substrate to be processed. In addition, the trench in the substrate surface portion having an etching stop layer formed on the surface is buried with an insulating film by bias ECRCVD, and at least a part of the insulating film outside the trench is removed by horizontal back etching to remove the etching. Before removing the etching stop layer, remove the etching layer to ensure that the stop layer is removed smoothly and reliably. It removes the oxide film generated during the horizontal return etching on the surface of the top layer, and also removes the insulating film outside the trench and the insulating film inside the trench that protrudes from the substrate surface by removing the etching stop layer. In order to remove at least a part of the protruding upper end portion, horizontal return etching is performed.

(C. Background Art) [FIG. 7] Conventionally, isolation between elements of a semiconductor device such as an IC, LSI, or VLSI is performed by a selective oxide film (LOCOS) formed by selectively oxidizing a surface portion of a semiconductor substrate. It was normal. However, the element isolation method using a selective oxide film has a disadvantage that a bird's beak is generated and a dimensional conversion difference is increased, so that it is becoming difficult to cope with miniaturization of the element. Therefore, attention has been paid to a trench isolation method in which bird's beaks are not generated and the difference in dimensional conversion is very small.

The trench isolation method is disclosed in, for example, JP-A-57-176742 or JP-A-60-53045.
A trench (groove) is formed in a surface portion of a semiconductor substrate, and the trench is filled with SiO ₂ by bias ECRCVD.

7A to 7E are sectional views showing an example of such a trench isolation method in the order of steps.

(A) On the surface of the semiconductor substrate 1, as shown in FIG.
A pad layer 7 made of SiO ₂ and an etching stop layer 6 made of polycrystalline silicon serving as a stopper for the etching of the trench filling insulating film are formed. The thickness of the etching stop layer 6 is, for example, about 500 to 2000 °.

(B) Next, a trench 2 is formed in the surface of the semiconductor substrate by anisotropic etching as shown in FIG.

(C) Next, as shown in FIG. 1 (C), the trench 2 is filled with an insulating film 3 made of SiO ₂ without excess or shortage by bias ECRCVD. The bias ECRCVD conditions are, for example,
SiH ₄ (17.5SCCM) / N ₂ O (35SCCM), microwave (2.45GH
The power of z) is 1000 W, the power of RF bias is 500 W, the magnetic field is 875 Gauss, and the pressure is 7 × 10 ^-4 Torr. 3a is an insulating film grown outside the trench, that is, in the active region.

(D) Next, as shown in FIG. 3D, the insulating film 3a is horizontally returned etched by bias ECRCVD under the condition that the flat surface is not etched.

Here, horizontal return etching refers to etching performed on a flat surface under conditions that the etching rate and the deposition rate are substantially equal, and for an angled surface, the etching rate is higher than the deposition rate. This is called horizontal return etching because the side surface of the insulating film outside the trench is etched so as to recede in the horizontal direction.

The bias ECRCVD conditions at this time are the same as those in the step (C) except that only the supply amount of SiH ₄ is changed to, for example, 7 SCCM or less, and other conditions may be left as they are.

In FIG. 7D, the two-dot chain line indicates the state of the insulating films 3 and 3a before the horizontal return etching.

(E) Further, the horizontal return etching is advanced or the insulating film 3a in the trench 2 is masked with a resist film to perform the etching to completely remove the insulating film 3a outside the trench as shown in FIG. To be removed.

The etching stop layer 6 is formed in order to prevent the surface of the substrate 1 from being etched when the insulating film 3a is removed and to prevent the substrate 1 from being damaged. This is for preventing the surface of the semiconductor substrate 1 from being etched when removing 6 by etching.

(D. Problems to be Solved by the Invention) [FIGS. 8 and 9
FIG.] By the way, the above-described trench isolation method has several problems.

First, there is a problem that it is difficult to further increase the throughput because the insulating film outside the trench is removed by horizontal return etching by bias ECRCVD.

This problem is specifically described as follows. When the insulating film outside the trench is subjected to horizontal back etching by bias ECRCVD, the insulating film is buried and the insulating film outside the trench is removed (the space for forming the resist mask for complete removal or etching for complete removal is secured. Can be continuously performed in the same ECRCVD apparatus, and it can be said that throughput is good in that respect. However, the rate of horizontal return etching in bias ECRCVD is the difference between the etching rate and the deposition rate, and the reaction efficiency of the reaction gas is lower than that of bias ECRCVD itself RIE. Therefore, the rate of horizontal return etching does not become too large. Therefore, it is difficult to meet the demand for improving the throughput for reducing the manufacturing cost of the semiconductor device for improving the productivity. And this is the problem.

In addition, after the trench on the surface of the substrate in which the etching stop layer made of polycrystalline silicon was formed on the surface of the semiconductor substrate was buried with an insulating film, and the insulating film outside the trench was horizontally returned etched by bias ECRCVD, as shown in FIG. As shown in the figure, a thick oxide film 8 is formed on the surface of the etching stop layer 6, and there is a problem that the etching stop layer 6 cannot be removed smoothly after the horizontal return etching. FIG. 8 is a cross-sectional view showing a photograph of the cross section of the semiconductor device after the horizontal return etching actually taken by SEM.

That is, when the insulating film outside the trench is horizontally returned etched by bias ECRCVD, the surface of the etching stop layer 6 made of polycrystalline silicon is plasma-oxidized, and a thin oxide film 8 is formed on the surface of the etching stop layer 6. After the horizontal return etching of the insulating film outside the trench, the etching stop layer 6 which has finished the role of protecting the substrate surface is removed by, for example, wet etching using KOH or dry etching using a gas such as Cl ₂ / HCl. Although it is necessary, if the thin oxide film 8 exists on the surface of the etching stop layer 6 made of polycrystalline silicon, the etching stop layer 6 cannot be completely etched. This is a problem because it hinders the surface of the single-crystal semiconductor substrate 1 from being exposed clearly.

When the trench in the substrate on which the etching stop layer made of polycrystalline silicon is formed is buried, the insulating film outside the trench is removed, and the etching stop layer and the pad layer are further removed. There is a problem that the upper end of the third 3 protrudes from the surface of the semiconductor substrate 1 as shown in FIG.

That is, the etching stop layer 6 and the pad layer 7
When the trench 2 in the surface portion of the semiconductor substrate 1 having the surface formed thereon is filled by bias ECRCVD, the in-trench insulating film 3 is formed so that its surface is at the same height as the surface of the etching stop layer 6, but outside the trench. If the etching stop layer 6 and the pad layer 7 are removed after the removal of the insulating film 3a, the upper end of the in-trench insulating film 3 necessarily projects from the surface of the semiconductor substrate 1. 3b is the protrusion.

The presence of such protrusions 3b causes a step on the surface of the semiconductor substrate 1 and hinders the achievement of a flat trench isolation, which is problematic and generally needs to be removed.

The present invention has been made to solve such a problem, and aims at improving the throughput, enabling complete removal of the etching stop layer, and further reducing the portion of the insulating film that fills the trench from the substrate surface. It is intended to enable removal and flat trench isolation.

(E. Means for Solving the Problems) A first aspect of the present invention is a bias EC embedding an insulating film.
Subsequent to RCVD, horizontal return etching of the insulating film outside the trench is performed by RIE.

According to a second aspect of the present invention, a gate valve for opening and closing a plasma extraction window is provided in an ECRCVD apparatus, and a high-frequency voltage for forming plasma can be applied between the gate valve and a support for supporting a substrate to be processed. It is characterized by doing so.

A third aspect of the present invention is characterized in that before removing the etching stop layer, an oxide film generated during horizontal return etching to the surface of the etching stop layer is removed.

A fourth aspect of the present invention is characterized in that a portion of the insulating film filling the trench protruding from the substrate surface is removed by horizontal return etching.

(F. Function) According to the first aspect of the semiconductor device of the present invention, the horizontal return etching of the insulating film outside the trench is performed by RIE where the gas use efficiency is higher than the bias ECRCVD and the etching rate is higher, so that the throughput is increased. Can be increased.

According to the second aspect of the present invention, an RIE apparatus for performing RIE in an ECRCVD apparatus in a reaction chamber by closing a plasma extraction window with a gate valve and applying a high-frequency voltage between the gate valve and a substrate support to be processed. Can function as

Therefore, the trench filling with the insulating film by the bias ECRCVD and the horizontal return etching by the RIE with a high etching rate can be continuously performed. Therefore,
This can contribute to an improvement in throughput.

According to the third aspect of the present invention, since the oxide film formed on the surface of the etching stop layer during the horizontal return etching is removed, the subsequent removal of the etching stop layer can be performed smoothly and reliably. Become.

According to the fourth aspect of the present invention, at least a part of the portion of the insulating film in the trench that protrudes from the substrate surface is etched back horizontally. It is possible to realize a flat trench isolation with no possibility of occurrence.

(G. Example) [FIGS. 1 to 6] Hereinafter, a method for manufacturing a semiconductor device of the present invention and EC used therein will be described.
The RCVD apparatus will be described in detail according to the illustrated embodiment.

(A. First Embodiment) [FIGS. 1 to 3] FIGS. 1A and 1B are cross-sectional views showing one embodiment of a method of manufacturing a semiconductor device of the present invention in the order of steps.

(A) A trench ECRC is formed on a surface of a semiconductor substrate 1 having a pad layer 7 made of SiO ₂ and an etching stop layer 6 made of polycrystalline silicon on the surface.
The insulating film 3 made of SiO ₂ is filled by VD. FIG. 3A shows a state after the burying by the insulating film 3.

The conditions of this bias ECRCVD are, for example, when the supply amount of SiH ₄ is
10 SCCM, N ₂ O of the feed rate is 35 SCCM, chamber the gas pressure is 7 × 10 ^-4 Torr, the power of the microwave (2.45GH _z) 1KW,
The bias RF power is 0.5KW and the magnetic field is 875 gauss.

 3a is an insulating film grown outside the trench.

(B) Next, without exposing the substrate 1 to the atmosphere,
It will be clear later what the IE room looks like. )
Then, the outer insulating film 3a outside the trench is horizontally etched back by RIE as shown in FIG.

The conditions of this RIE are, for example, the supply amount of SiH ₄ is 15 SCCM, the supply amount of N ₂ O is 35 SCCM, the supply amount of argon Ar is 75 SCCM, the internal pressure is 1 × 10 ⁻² Torr, and the power of RF is 0.2 Wcm ⁻² . .

When horizontal return etching is performed by RIE in this way,
Compared to the case where horizontal return etching is performed by bias ECRCVD, the utilization efficiency of the source gas is higher and the plasma can be generated near the surface of the semiconductor substrate 1, so that the energy of the etchant can be increased. Therefore, the etching rate can be increased.

(A-1. One example of ECRCVD apparatus) [Fig. 2] Fig. 2 shows the burying of insulating film by bias ECRCVD and RI.
FIG. 3 is a cross-sectional view showing an example of an ECRCVD apparatus suitable for continuously performing horizontal return etching of an insulating film outside a trench by E.

In the figure, reference numeral 9 denotes a plasma generation chamber made of quartz;
In the waveguide, guiding microwave generated from the magnetron 11 (2.45GH _z) 12 to the plasma generation chamber 9. Reference numeral 13 denotes a solenoid coil for creating a magnetic field in the plasma generation chamber 9. The plasma of the gas supplied into the plasma generation chamber 9 is generated by a synergistic effect of the microwave 12 and the magnetic field. Reference numeral 14 denotes a reaction chamber disposed below the plasma generation chamber 9 and communicates through a plasma extraction window 15. A support for mounting the semiconductor substrate 1 in the reaction chamber 14
A gas pipe 17 receives a gas such as SiH ₄ . Then, the plasma generated by the plasma generation chamber 9 is extracted onto the semiconductor substrate 1 through the plasma extraction window 15, and is biased onto the semiconductor substrate 1 by bias ECR CVD.
Progresses. Reference numeral 18 denotes a high frequency power supply for bias.

Reference numeral 19 denotes an RIE chamber, and the reaction chamber 14
The gate valve 20 is opened, and the semiconductor substrate 1 can be moved from the inside of the reaction chamber 14 to the inside of the RIE chamber 19 by moving means (not shown). 21 is RIE room 1
9 is a support for supporting the semiconductor substrate 1 in 9;
An upper electrode facing the upper side of 1 and a high frequency voltage for plasma generation is applied between the upper electrode and the support 21. 23 is a high frequency power supply for generating the plasma.

In the RIE room 19, parallel plate type RIE can be performed.

Thus, the formation of the insulating film 3 in the reaction chamber 14 is biased.
After performing the ECRCVD, the semiconductor substrate 1 can be moved to the RIE chamber 19 and subsequently the horizontal return etching of the insulating film 3 by RIE can be performed.

Note that it is also possible to connect the plurality of bias ECRCVD chambers and the RIE chamber appropriately via a gate valve, and to perform each step continuously while passing the semiconductor substrate through each chamber.

(A-2. Another Example of ECRCVD Apparatus) [FIG. 3] FIG. 3 is a longitudinal sectional view of another example of the ECRCVD apparatus suitable for carrying out the method of manufacturing the semiconductor device shown in FIG.

This ECRCVD apparatus has many parts in common with a general ECRCVD apparatus, but differs in the following points.

A gate valve 24 for opening and closing the plasma extraction window 15 is provided in the reaction chamber 14, and a high-frequency voltage for forming plasma between the gate valve 24 and the support 16 can be applied. Although at least a main part of the gate valve 24 is made of a conductor, the surface may be covered with an insulating film such as Teflon. The portion closing the plasma extraction window 15 is made of an insulating material.

When performing the bias ECRCVD, the gate valve 24 is kept in a state where the plasma extraction window 15 is not closed, and the high frequency voltage is not applied between the gate valve 24 and the support 16 in the same manner as the normal bias ECRCVD.

Then, when performing RIE after the bias ECRCVD, the plasma extraction window 15 is closed by the gate valve 24 as shown in FIG. 3, and a high-frequency voltage for plasma formation is applied between the gate valve 24 and the support 16. Then, an etching gas is supplied from the gas pipe 17.

Even with such an ECRCVD apparatus, the filling of the trench with the insulating film by the bias ECRCVD and the horizontal return etching by the RIE of the insulating film outside the trench can be continuously performed.

Incidentally, reference numeral 25 denotes an exhaust pipe for exhausting the plasma generation chamber 9, and reference numeral 26 denotes an electromagnetic valve for opening and closing the exhaust pipe 25. The exhaust pipe 25 is for cleaning the inside of the plasma generation chamber 9 by plasma. The plasma extraction window 15 is closed by the gate valve 24, and in this state, plasma is generated by the exhaust pipe 25 while generating plasma in the plasma generation chamber 9. By exhausting the generation chamber 9, the reaction products attached to the inner surface of the plasma generation chamber 9 can be removed, and thereby particles can be prevented. However, the mechanism for plasma cleaning the inside of the plasma generation chamber 9 is not always essential.

(B. Second Embodiment) [FIGS. 4 to 6] FIGS. 4 (A) to 4 (E) are sectional views showing a second embodiment of the method of manufacturing a semiconductor device of the present invention in the order of steps. .

(A) The trench 2 is filled with the insulating film 3 in the same manner as in the method of manufacturing the semiconductor device shown in FIG. FIG. 4A shows a state after the embedding is completed.

(B) Next, as shown in FIGS. 7D and 7E, the insulating film 3a outside the trench is removed by horizontal return etching by bias ECRCVD. In the bias ECRCVD at the time of the horizontal return etching, only the supply amount of SiH ₄ of the source gas is changed among the conditions at the time of the filling.

Then, the insulating film outside the trench 3a is removed. But,
The surface of the etching stop layer 6 made of polycrystalline silicon is plasma-oxidized. Reference numeral 8 denotes a plasma oxide film formed on the surface of the etching stop layer 6 by the plasma oxidation. FIG. 4B shows the state after the horizontal return etching.

(C) Next, NF ₃ + Ar as an etching gas for the silicon oxide film as a source gas (NF ₃ is diluted with Ar which is one of inert gases. It may be diluted with another inert gas. ) Is supplied to perform dry etching on the silicon oxide film 8.

In this dry etching, after the horizontal return etching, the subsequent conditions are the same in the same ECRCVD apparatus, for example, the supply amount of NF ₃ is 40 SCCM, the power of the microwave is 1000 W, the internal pressure is 1 × 10 ^-3 Torr, and the magnetic field is 875 gauss. It can be done by creating.

By this dry etching, the etching stop layer 6 is formed.
Silicon oxide film 8 and etching stop layer 6 on the surface of
It can remove its own surface layer. FIG. 4C shows the state after the dry etching.

FIG. 5 is a cross-sectional view depicting a photograph of a cross section of the semiconductor device actually finished with the dry etching taken by a scanning electron microscope (SEM). From the comparison between FIG. 5 and FIG. It is clear that 8 has been completely removed.

(D) Next, as shown in FIG. 4 (D), the etching stop layer 6 made of polycrystalline silicon is removed by, for example, wet etching using KOH or dry etching using a gas such as Cl ₂ / HCl. I do.

(E) Next, a portion 3b of the insulating film 3 protruding from the substrate 1 in the trench 2 is removed by horizontal return etching by bias ECRCVD as shown in FIG.

Bias ECRCVD condition at this time is, for example, microwave power 1000W, the bias RF power is 500W of (2.45 GHz _z), following the supply amount of SiH ₄ is 15 SCCM (e.g. 7 sccm), N
The supply amount of ₂ O is 35 SCCM, the internal pressure is 1.6 × 10 ⁻³ or less (for example, 7 × 10 ⁻⁴ Torr), and the magnetic field is 875 gauss. Note that Ar, which is an inert gas, may be added to the source gas, for example, at about 72 SCCM. Under this condition, the etching rate is substantially equal to the deposition rate for a flat surface (horizontal surface), and the etching rate is higher than the deposition rate for an angled surface. Only the portion 3b protruding from the surface of the semiconductor substrate 1 can be removed.

Note that horizontal return etching is initially faceted (fa
corner 3c of the projecting portion 3b of the insulating film 3 due to the cetting) effect.
[See FIG. 4 (D)], the cross-sectional shape of the protrusion 3b becomes trapezoidal, and then the width of the protrusion 3b gradually decreases.

In the method of manufacturing the semiconductor device, horizontal return etching for removing the protruding portion 3b of the insulating film 3 is performed by bias ECR CVD.
Instead, the RIE may be performed similarly to the removal of the insulating film 3a outside the trench in the method for manufacturing the semiconductor device shown in FIG. It is apparent from the above that the throughput can be improved by doing so. Incidentally, it goes without saying that also in the method of manufacturing the semiconductor device, the horizontal return etching [see FIG. 4 (B)] for removing the insulating film 3a outside the trench may be performed not by bias ECRCVD but by RIE. .

6 (A) and 6 (B) show a modification of the method of manufacturing the semiconductor device shown in FIG. 4 in the order of steps.

In this modification, when the trench 2 is formed in a tapered shape, the corner 3c of the portion 3b of the insulating film 3 filling the trench 2 and protruding from the surface of the semiconductor substrate 1 is faceted (fa).
cetting) effect.
The reason why the trench 2 is formed in a tapered shape is to facilitate the filling with the insulating film 3.

(A) FIG. 6 (A) shows a state in which the trench 2 has been filled with the insulating film 3, the insulating film outside the trench 2 has been removed, and the etching stop layer 6 has been removed. In this case, when a gate material or the like is formed thereafter, the protrusion 3b of the insulating film 3 is formed.
There is a case where the gate material is masked by the insulating film 3 at the corner 3c of FIG. Therefore, it is necessary to remove at least the corner 3c.

(B) Next, the corner 3c is removed by horizontal return etching as shown in FIG. This can prevent the gate material from being short-circuited.

The protrusion 3b may be completely removed in addition to removing the corner 3c. However, in the case where the protrusion 3b is intentionally left to prevent the thinning during gate oxidation. The horizontal return etching is stopped when the corner 3c is removed by the faceting effect.

However, in many cases, it is better to completely remove the protrusion 3b. In this case, it is necessary to continue the horizontal return etching until the protrusion 3b disappears. In such a case, all of the horizontal return etching is performed by bias ECRCVD.
Only, or RIE may be performed first lightly and then performed by bias ECRCVD. This is because RIE provides a good faceting effect. Conditions in this case include, for example,
Source gas is CHF ₃ (75SCCM) / O ₂ (8SCCM), gas pressure is 50
mTorr and RF power for plasma generation of 0.25 W / cm ² are good.

However, various variations are conceivable such that the entire horizontal return etching may be performed by RIE.

(H. Effects of the Invention) As described above, the first aspect of the present invention is a method of forming a trench EC on a substrate having a trench formed on the surface thereof.
It is characterized by burying with an insulating film formed by RCVD, and subsequently performing bias ECRCVD by RIE on the insulating film grown outside the trench during the filling.

Therefore, according to the first aspect of the present invention, the horizontal return etching of the insulating film outside the trench is performed by using the RI in which the gas use efficiency is higher and the etching rate is higher than the bias ECRCVD.
Since this is performed by E, the throughput can be increased.

A second aspect of the present invention is an ECRCVD apparatus including a plasma generation chamber for generating plasma using electron cyclotron resonance, and a reaction chamber in which a substrate to be processed is disposed and communicates with the plasma generation chamber through a plasma extraction window. Wherein a gate valve made of a conductor and opening and closing the plasma extraction window is provided, and a high-frequency voltage for plasma formation can be applied between the gate valve and a support for supporting a substrate to be processed. Is what you do.

Therefore, according to the second aspect of the present invention, the plasma extraction window is closed by a gate valve, and a high-frequency voltage is applied between the gate valve and the substrate to be processed. It can function as a RIE device to perform.

Therefore, the trench can be buried in the insulating film by the bias ECRCVD and the horizontal return etching by the RIE having a high etching rate can be continuously performed, and the throughput can be improved.

According to a third aspect of the present invention, a trench formed in a surface portion of a substrate having an etching stop layer for protecting a base in a horizontal return etching described later is formed on a surface of a substrate by a bias EC.
Embedded in an insulating film formed by RCVD, and then performing horizontal back etching on the insulating film formed outside the trench at the time of the embedding, and thereafter, removing the etching stop layer, the method for manufacturing a semiconductor device, After the horizontal return etching and before removing the etching stop layer, a step of removing a thin insulating film generated at the time of the horizontal return etching on the surface of the polycrystalline silicon layer is provided.

Therefore, according to the third aspect of the present invention, since the oxide film formed on the surface of the etching stop layer during the horizontal return etching is removed, the subsequent removal of the etching stop layer can be performed smoothly and reliably. Will be possible.

According to a fourth aspect of the present invention, a trench formed in a surface portion of a substrate having an etching stop layer for protecting a base during horizontal return etching described later is formed on a surface of a substrate by a bias EC.
Embedded in an insulating film formed by RCVD, and then performing horizontal back etching on the insulating film formed outside the trench at the time of the embedding, and thereafter, removing the etching stop layer, the method for manufacturing a semiconductor device, After removing the etching stop layer, at least a portion of a portion of the insulating film filling the trench protruding from the surface of the substrate is removed by horizontal return etching.

Therefore, according to the fourth aspect of the present invention, at least a part of the portion of the insulating film in the trench that protrudes from the substrate surface is etched back horizontally. It can be removed so as to achieve flat trench isolation without any problem.

[Brief description of the drawings]

1 (A) and 1 (B) are cross-sectional views showing one embodiment of a method of manufacturing a semiconductor device of the present invention in the order of steps, and FIGS. 2 and 3 are ECRCVD apparatuses suitable for a method of manufacturing a semiconductor device. FIGS. 4A to 4E are cross-sectional views showing another embodiment of the method of manufacturing a semiconductor device of the present invention in the order of steps, and FIGS.
FIG. 6 is a cross-sectional view showing a SEM photograph of a cross section of the semiconductor device after removing an oxide film from the surface of the etching stop layer. FIGS. 6A and 6B are views for manufacturing the semiconductor device shown in FIG. 7A to 7E are cross-sectional views showing the background art in the order of steps, and FIG. 8 is an etching showing one problem to be solved by the invention. FIG. 9 is a cross-sectional view showing a SEM photograph of a cross section of the semiconductor device in which an oxide film is formed on the surface of the stop layer. FIG. 9 is a cross-sectional view showing another problem to be solved by the present invention. DESCRIPTION OF SYMBOLS 1 ... substrate, 2 ... trench, 3 ... insulating film, 3a ... outside trench insulating film, 3b ... portion protruding from the substrate surface of trench inside insulating film, 6 ... etching stop layer, 8 …… Oxide film formed on the surface of the etching stop layer 9 …… Plasma generation chamber 14… Reaction chamber 15… Plasma extraction window 16… Support base 21… Support base 23… Plasma generation High frequency power supply for 24, gate valve.

Claims (4)

(57) [Claims] 1. A trench having a trench formed on a surface thereof is filled with an insulating film formed by bias ECRCVD. Subsequently, the insulating film grown outside the trench at the time of the filling is returned horizontally by RIE. Etching is performed, and a method of manufacturing a semiconductor device is performed. 2. An ECR CVD apparatus comprising: a plasma generation chamber for generating plasma using electron cyclotron resonance; and a reaction chamber in which a substrate to be processed is disposed and communicates with the plasma generation chamber through a plasma extraction window. A gate valve for opening and closing the plasma extraction window, wherein a high-frequency voltage for plasma formation can be applied between the gate valve and a support for supporting a substrate to be processed. 3. A trench formed on a surface portion of a substrate having an etching stop layer for protecting a base during horizontal return etching to be described later on the surface is buried with an insulating film formed by bias ECRCVD. A method for manufacturing a semiconductor device, comprising: performing horizontal return etching on an insulating film formed outside, and then removing the etching stop layer, wherein after the horizontal return etching and before removing the etching stop layer, A method of manufacturing a semiconductor device, comprising a step of removing a thin insulating film formed on the surface of a silicon layer during the horizontal return etching. 4. A trench formed on the surface of a substrate having an etching stop layer for protecting a base during horizontal return etching to be described later is buried with an insulating film formed by bias ECRCVD. A method for manufacturing a semiconductor device, comprising: performing horizontal return etching on an insulating film formed outside, and then removing the etching stop layer, wherein after removing the etching stop layer, the substrate of the insulating film filling the trench is removed. A method of manufacturing a semiconductor device, comprising removing at least a part of a portion protruding from a surface by horizontal back etching.