JP2002246348A - Method for manufacturing semiconductor device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] When planarizing a semiconductor wafer by a CMP method, it is possible to perform polishing without supplying a sufficient polishing liquid on a polishing cloth, to reduce waste of the polishing liquid, and to finish polishing. This eliminates the need for a monitor for detection, thereby preventing various problems associated with the use of the monitor. SOLUTION: A fine particle mixed film 8 containing fine particles 9 is formed on a semiconductor substrate 5 or a film 7 deposited on the surface thereof, and then a chemical mechanical polishing is performed. The semiconductor substrate or the coating is flattened by the fine particles that appear.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for processing a surface of a workpiece, for example, a chemical mechanical polishing (Chemical Mechanical Polishing) of a wafer substrate or a film deposited on the surface. Mechanical Poli
shing; CMP).

[0002]

2. Description of the Related Art When a wafer substrate is flattened at the stage of manufacturing a semiconductor device, the conventional CMP method performs polishing by pressing a wafer against a polishing cloth while supplying an abrasive liquid to the polishing cloth.

[0003] However, depending on the distribution of the polishing liquid to the polishing cloth, unevenness occurs in the flattening process. Therefore, a sufficient amount of the polishing liquid must be supplied onto the polishing cloth to prevent the occurrence of the unevenness. Had been discarded.

When it is desired to stop the polishing at the same time as the completion of the polishing, it is possible to stop the polishing by using a polishing end detection output from a monitor (for example, a torque monitor). There was a delay in the time until the actual stop of the polishing, and wasteful polishing occurred during that time. Further, depending on the detection accuracy of the monitor, the end of polishing may not be detected and polishing may be excessively performed.

[0005]

As described above, in the conventional CMP method for flattening a semiconductor wafer, a sufficient amount of polishing liquid must be supplied onto a polishing cloth, and a large amount of excessive polishing liquid is discarded. There is a problem that there is a delay in the time from the generation of the polishing completion detection output by the monitor until the polishing is actually stopped, and wasteful polishing occurs during that time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. When a semiconductor wafer is flattened by a CMP method, polishing can be performed without supplying a sufficient polishing liquid onto a polishing cloth. It is an object of the present invention to provide a method of manufacturing a semiconductor device which can save waste of the polishing liquid, eliminate the need for a monitor for detecting the completion of polishing, and eliminate various problems caused by use of the monitor.

[0007]

According to a method of manufacturing a semiconductor device of the present invention, a fine particle mixed film containing fine particles is formed on a surface of a workpiece, and then the surface of the workpiece is processed. Features.

In this case, as the fine particles, particles (CeO ₂ , ZrO) capable of shaving the surface of a workpiece.
₂ , Al ₂ O ₃ , MnO _2, etc.), when the workpiece (semiconductor substrate or a film deposited on the surface thereof) is planarized by the CMP method, the fine particle mixed film is used. The appearing fine particles allow the semiconductor substrate or coating to be polished.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

<First Embodiment> FIG. 1 shows a processing apparatus (polishing apparatus) used for flattening a semiconductor wafer by a CMP method according to a first embodiment of a method of manufacturing a semiconductor device of the present invention. 1 is schematically shown.

In FIG. 1, 1 is a polishing cloth placed on a rotatable turntable 6, 2 is a polishing liquid for supplying a polishing liquid 3 or pure water 3 to, for example, a central portion of the polishing cloth 1. It is a pure water supply nozzle. Reference numeral 4 denotes a top ring, which holds the back surface of the wafer 5 with the surface of the workpiece (wafer in this example) 5 facing the polishing cloth 1, and presses the surface of the wafer 5 against the polishing cloth 1. Can be rotated.

Next, the operation of the polishing apparatus will be briefly described.

The back surface of the wafer 5 is held by the top ring 4, the turntable 6 is rotated, and the abrasive liquid 3 or pure water 3 is supplied from the abrasive liquid supply nozzle 2 onto the polishing pad 1. Polishing is performed by rotating the wafer 5 while pressing the wafer against the polishing cloth 1.

FIGS. 2A to 2D are cross-sectional views schematically showing a mechanism for flattening a semiconductor wafer by a CMP method using the polishing apparatus of FIG.

First, as shown in FIG.
5 before polishing the film 7 to be polished, fine particles (CeO ₂ , ZrO ₂ , ZrO ₂ ,
Al ₂ O ₃ , MnO _2, etc.) are mixed to form a fine particle mixed film 8. Then, place pure water on the polishing cloth 1.
The surface of the wafer 5 is polished while supplying 3.

When the fine particle mixed film 8 starts to be polished, the fine particle mixed film 8 is removed from the fine particle mixed film 8 as shown in FIG.
When 9 comes out, the fine particle mixed film 8 itself is also polished.

The polishing proceeds as shown in FIG.
As shown in (d), when the polishing target film 7 is exposed, the fine particle mixed film 8 and the polishing target film 7 are simultaneously polished by the fine particles 9. Further, when the polishing proceeds and the flattening of the film-to-be-polished 7 is completed and the fine-particle mixed film 8 and the fine particles 9 disappear at the same time, there is no polishing agent for polishing the film-to-be-polished 7, and no polishing agent Since the polishing of the film-to-be-polished 7 is not promoted at this time, the polishing automatically ends.

During the polishing, since fine particles 9 serving as an abrasive are present closest to the film 7 to be polished, the polishing can be performed without causing polishing unevenness.

In other words, the method of flattening a semiconductor wafer by the above-described CMP method is a method in which fine particles 9 capable of shaving the surface of the film 7 to be polished are contained in a film that can be polished without a polishing liquid. By polishing after forming the particle mixed film 8 on the semiconductor substrate, the film 7 to be polished on the semiconductor substrate can be polished by the fine particles 9 in the fine particle mixed film 8. At this time, since the polishing can be performed while supplying the pure water 3 onto the polishing cloth 1, the polishing liquid is unnecessary.

<Second Embodiment> In the first embodiment,
Before polishing the film 7 to be polished of the wafer 5, a fine particle mixed film 8 was formed on the surface thereof by mixing the fine particles 9 with a film that can be polished without an abrasive liquid.

On the other hand, in the second embodiment, the first
Instead of the film that can be polished without a polishing liquid in the above embodiment, a fine particle mixed film is formed by mixing fine particles with a film (for example, an SOG film) that can be polished with a polishing liquid used in normal CMP. I do.

Thereafter, the surface of the wafer 5 is polished while supplying the polishing liquid 3 onto the polishing cloth 1. When the fine particle mixed film 8 starts to be polished, the fine particles 9 come out of the film, so that the fine particle mixed film 8 itself is polished. At this time, when the fine particles 9 come out, the supply of the polishing liquid 3 is switched to the supply of the pure water 3.

When the polishing proceeds and the film 7 to be polished is exposed, the fine particle 9 polishes the fine particle mixed film 8 and the film 7 to be polished simultaneously. Further, when the polishing proceeds and the flattening of the film-to-be-polished 7 is completed and the fine-particle mixed film 8 and the fine particles 9 disappear at the same time, there is no polishing agent for polishing the film-to-be-polished 7 and there is no polishing agent. Since the polishing of the film-to-be-polished 7 is not promoted at this time, the polishing is automatically terminated.

<Third Embodiment> FIGS. 3A to 3E
FIG. 7 is a cross-sectional view schematically illustrating a mechanism of flattening a semiconductor wafer by a CMP method according to a third embodiment.

First, as shown in FIG.
5 before the polishing of the film 7 to be polished, the fine particles 12 described in the first embodiment or the second embodiment are embedded and scattered on the surface thereof.
In this embodiment, a film (for example, a resist film or an SOG film) 13 used for mixing the fine particles is formed. Here, the combination of the fine particles 12 and the film 13 corresponds to the fine particle mixed film 8 described in the first embodiment or the second embodiment.

Alternatively, as shown in FIG. 3E, before polishing the film 7 to be polished of the wafer 5,
The fine particles 12 described in the first or second embodiment and a film (for example, a resist film or an SOG film) used to mix the fine particles in the first or second embodiment 13 Are embedded in, for example, three layers, and then the film (eg, a resist film or SOG) used to mix fine particles in the first embodiment or the second embodiment is used.
A film 13 is formed. Here, the combination of the fine particles 12 and the film 13 corresponds to the fine particle mixed film 8 described in the first embodiment or the second embodiment.

In the case where the film 13 is a resist film, the wafer 5 is thereafter supplied while supplying only pure water 3 onto the polishing cloth 1 as shown in FIG. Is polished. As shown in FIG. 3C, when the film 13 starts to be polished, fine particles 9 come out of the film 7 to be polished, so that the film 13 itself is polished.

On the other hand, when the film 13 is an SOG film, the polishing liquid 3 is then supplied onto the polishing cloth 1 as shown in FIG. Wafer while
Polish the surface of 5. When the film 13 starts to be polished as shown in FIG. 3C, fine particles 9 come out of the film 7 to be polished, and the film 13 itself is polished. At this time, when the fine particles 9 come out, the supply of the polishing liquid is switched to the supply of pure water.

When the polishing proceeds and the film to be polished 7 is exposed, the film 13 and the film to be polished 7 are simultaneously polished by the fine particles 9. Further, as the polishing proceeds, as shown in FIG. 3 (d), when the flattening of the film 7 to be polished is completed and the film 13 and the fine particles 9 disappear at the same time, a polishing agent for polishing the film 7 to be polished becomes And the polishing of the film to be polished 7 is not promoted without the polishing agent, so that the polishing is automatically terminated.

That is, the CM used in the conventional flattening process
In the P method, the polishing is performed by pressing the wafer 5 against the polishing cloth 1 while supplying the polishing liquid 3 onto the polishing cloth 1, so that unevenness may occur in the flattening process depending on how the polishing liquid 3 spreads on the polishing cloth 1. However, in the CMP method of the present invention, since the fine particles 9 serving as the abrasive are present closest to the object to be polished during polishing, the polishing can be performed without causing polishing unevenness.

In addition, since fine particles 9 serving as an abrasive are present in the film being polished, an unnecessary polishing liquid is not required, and the processing cost is reduced. In particular, when a film that can be polished only with pure water 3 is used, no polishing liquid is used, and therefore a polishing liquid supply device is not required.

Further, the fine particles 9 disappear (there is no abrasive) at the end of the flattening of the film 7 to be polished, so that the polishing can be finished at the same time as the end of the flattening. At this time, since a monitor (for example, a torque monitor) for detecting the end of the planarization is not required, there are various problems associated with the use of the monitor (wasteful polishing due to a delay in time from the end of the planarization to the stop of the polishing, the monitor). Also, excessive polishing due to erroneous detection does not occur, and unnecessary polishing is not performed after the planarization is completed, so that the in-plane uniformity of the film to be polished is not deteriorated after the planarization is completed.

[0033]

As described above, according to the method for manufacturing a semiconductor device of the present invention, when a semiconductor wafer is flattened by a CMP method, polishing can be performed without supplying a sufficient polishing liquid on the polishing cloth. As a result, waste of the polishing liquid can be saved, and a monitor for detecting the completion of polishing becomes unnecessary, and various problems associated with the use of the monitor can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view schematically showing an example of a processing apparatus (polishing apparatus) used when flattening a semiconductor wafer by a CMP method according to a first embodiment of a method for manufacturing a semiconductor device of the present invention. .

FIG. 2 is a cross-sectional view schematically showing a mechanism for flattening a semiconductor wafer by a CMP method using the polishing apparatus of FIG. 1;

FIG. 3 is a cross-sectional view schematically illustrating a mechanism of flattening a semiconductor wafer by a CMP method according to a third embodiment of the present invention.

[Explanation of symbols]

 1… abrasive cloth, 2… abrasive / pure water supply nozzle 3… pure water or abrasive liquid, 4… top ring, 5… workpiece (wafer), 6… turntable, 7… polished film, 8… fine Particle mixed film, 9 ... fine particles.

Claims (7)

[Claims] 1. A method for manufacturing a semiconductor device, comprising: forming a fine particle mixed film containing fine particles on a surface of a workpiece; and thereafter processing the surface of the workpiece. 2. The method according to claim 1, wherein the fine particles are particles capable of shaving the surface of a workpiece.
The manufacturing method of the semiconductor device described in the above. 3. The fine particles are made of CeO._Two , ZrO_Two ,
Al_Two O_Three , MnO _Two Characterized by one of the following:
A method for manufacturing a semiconductor device according to claim 2. 4. The object to be processed is a semiconductor substrate or a film deposited on the surface thereof, and the semiconductor substrate or the film is chemically and mechanically polished, and the fine particles appearing from the fine particle mixed film accompanying the chemical mechanical polishing. 4. The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor substrate or the coating is flattened with particles. 5. 5. When forming the fine particle mixed film, the semiconductor substrate or a film deposited on a surface thereof is formed by mixing the fine particles into a film that can be polished without an abrasive liquid, and the semiconductor substrate is formed. The chemical mechanical polishing of the semiconductor substrate or the coating is performed while supplying pure water onto the polishing cloth when performing the chemical mechanical polishing of the coating. Of manufacturing a semiconductor device. 6. When forming the fine particle mixed film, a semiconductor substrate or a film deposited on the surface thereof is formed by mixing fine particles into a film that can be polished with an abrasive liquid, and then forming a polishing cloth. Performing chemical mechanical polishing of the semiconductor substrate or coating while supplying the abrasive liquid on the top, when the fine particles come out from the fine particle mixed film, switching from the supply of the abrasive liquid to the supply of pure water The method for manufacturing a semiconductor device according to claim 1, wherein polishing is continued. 7. The manufacturing of a semiconductor device according to claim 4, wherein the polishing is automatically stopped when the fine particles do not appear after the flattening process is completed. Method.