JPH0468527A - Method and apparatus for removing particle from cleaned body - Google Patents

Abstract

PURPOSE:To certainly eliminate particles one by one from a wafer by detecting particles one by one on a cleaned body, storing each position of respective particles detected and then irradiating the cleaned body with an energy beam. CONSTITUTION:A cleaned body 1, as a material to be rinsed, is placed on a wafer support base 11 for scanning, particles 10 are detected by utilizing reflection of a laser beam 12 and the coordinates of detected position is stored in a memory 2. Next, the particles detected are eliminated from each position stored. Namely, using, for example, the He gas ion source, a beam is focused about to 0.1mum with an ion beam apparatus to irradiate each particle detected with the ion beam 30. Each particle 10 is heated and evaporated by the ion beam 30 and thereby particles may be eliminated. Thereby, a wafer having high reliability may be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for removing particles from an object to be cleaned. The present invention can be used as a technique for removing particles attached to various objects to be cleaned, and can be used for various objects to be cleaned, such as semiconductor substrates, various substrates having transparent films, thin film magnetic head substrates, etc.
Especially minute electronic parts (substrate wafers for semiconductor integrated circuits, etc.)
It can be preferably used for cleaning objects to be cleaned where it is desired to completely remove and clean even extremely small particles.

[Summary of the invention]

In the present invention, each particle existing on the object to be cleaned is
By detecting particles, storing each position of each detected particle, and removing particles one by one from each stored position, it is possible to remove particles reliably and completely. Therefore, when used for cleaning wafers of semiconductor devices, for example, it is possible to improve product yield.

[Conventional technology and problems to be solved]

BACKGROUND ART Conventionally, cleaning by removing particles on an object to be cleaned has been carried out in various fields, and for example, such cleaning has been carried out in cleaning semiconductor wafers during the manufacture of semiconductor devices.

In the field of semiconductor devices, the miniaturization of devices is progressing more and more, for example, the miniaturization of semiconductor integrated circuits is progressing steadily, and we are at the stage where devices with a 0.5 μm rule are being prototyped. As a result, reduction in yield due to particles adhering to semiconductor wafers and the like during the manufacturing process has become an increasingly serious problem. Therefore, a technology is desired that can reliably and completely remove the attached particles.

Against this background, efforts are being made to reduce particle adhesion in each manufacturing process of semiconductor device manufacturing, and at present, the number of particles of 0.3 μm or more per wafer has been reduced to a few to several dozen particles. It has reached the point where However, in delicate and minute devices such as semiconductor integrated circuits, it is desirable that not even a single particle exists.

However, in the conventional technology, particles are detected and removed all at once by cleaning or the like, but this is no longer the case. That is, since the conventional technology cleans and removes particles all at once, complete removal is not necessarily performed for each particle. Therefore, in the past, even if there were only a few problematic particles, no technology had been established that could reliably and completely remove them.

[Purpose of the invention]

The present invention solves the above problems and provides a particle removal method and a particle removal device that can reliably remove each particle on an object to be cleaned.

[Means for Solving the Problems] In order to achieve the above object, the particle removal method of the present invention detects particles existing on the object to be cleaned one by one, and removes each detected particle one by one. Each position is stored, and particles are removed one by one for each stored position.

Further, the particle removal device of the present invention has a control system having at least a particle detection means for detecting particles present on the object to be cleaned one by one, and a storage section for storing each position of each detected particle. and a particle removing means for removing particles one by one by energy irradiation.

[For production]

According to the present invention, particles are detected one by one on the object to be cleaned, their positions are memorized, and the particles are removed at each detection position, so particles are reliably and completely removed. can be removed.

As mentioned above, in the field of semiconductor device manufacturing, for example, there are only a few to a few dozen particles per wafer, so it is not difficult to perform such individual operations, but rather it is difficult to completely clean and remove them. is extremely sloppy.

〔Example〕

Examples of the present invention will be described below. However, it goes without saying that the present invention is not limited to the examples described below.

Example 1 This example describes how to remove particles present on a semiconductor wafer during the manufacture of a fine semiconductor integrated circuit device.
This is an application of the present invention.

As shown schematically in FIG. 1, this embodiment detects particles existing on an object to be cleaned (in this case, a semiconductor wafer) one by one. )
, each position of each detected particle is memorized (indicated by symbol ``■''), and particles are removed one by one from each of the stored positions (indicated by symbol ``■'').

As for the apparatus, the particle detection I is carried out using an appropriate particle detection means, for example, polarized laser light.
This can be carried out by a particle detection means that detects each particle one by one, the storage (1) is carried out by a control unit having at least a storage section that stores each position of each detected particle, and the particle removal (2) is carried out by energy irradiation. It is constructed by a particle removing means that removes particles one by one.

More specifically, the particle removal device of this example is as follows:
The configuration is illustrated in FIG.

The particle detection means detects a wafer, which is the object to be cleaned 1, by
Particles 10 are detected using the reflection of the laser beam 12 while being scanned on the mounting table (wafer table) 11, and the detected position coordinates are stored in the memory section 2. In the figure, 13 is a laser light source, and 14 is a mirror forming an optical system that controls the laser light from the laser light source. 15 is a lens constituting an optical system that controls the laser light that passes over the object to be cleaned (wafer) 1, which is the object to be inspected; and 16 is a detector. Here, the particles IO are detected using the polarization of laser light, and this method will be described later.

In the apparatus of this embodiment, the control section 20 has at least a memory section 2 for storing detected positions, but in this embodiment, it further independently includes a drive control section 21. The drive control unit 21 issues a signal to the drive system 17 (consisting of a motor as a drive source, its transmission system, etc.) that drives the mounting table 11, and controls it.
The mounting table 11 is moved to scan the wafer, which is the object to be cleaned 1. The memory unit 2 also receives a signal from the detector 16 and receives a signal from the detector 16.
The detected position signal is sent to the detector 16, and the detector 16 is moved as necessary. It also plays the role of driving each mechanism of the particle removing means described below.

In this embodiment, the position of each particle 10 detected by the detection means is stored in the memory section 2. By performing particle removal for each stored position, each particle is completely removed.

In this embodiment, the particle removing means removes particles one by one by irradiating energy, and the irradiating energy can be any type of energy that can remove particles, such as electron beams, heat rays, or other radiation. An ion beam was used here. Specifically, this uses a focused ion beam gun,
It consists of an ion beam source indicated by reference numeral 31 in the figure, a beam control system such as a converging lens indicated at 32, and a scanning electrode indicated at 33. The ion beam is designated by 30. A device that can be specifically used as an ion beam device will be described later.

With such an ion beam device, a beam is focused to about 0.1 μm using, for example, a He gas ion source, and the ion beam 30 is irradiated onto each particle whose position has been detected by the above-mentioned detection means. Each particle 10 is heated by the ion beam 30 and evaporated, thereby removing the particle.

Even if an electron beam is used instead of an ion beam, it can be converged to the same extent and can be used in exactly the same way.

Further, during this removal, an etching gas may be flowed to facilitate particle removal.

For example, if the particles are silicon-based (
For example, when SiO□ or poly-Si becomes particles, a fluorine-based gas such as CF4 can be flowed, and when it is an Ai-based material (such as when A! is used as a wiring material), By flowing a chlorine-based gas such as , CIZ, etc., the removal efficiency can be increased. others,
In the case of a W-based gas, a fluorine-based gas may be used or other suitable methods may be used.

In this embodiment, a device using polarized laser light was used as a means for detecting particles on the object to be cleaned 1 (Ueno\). In other words, when simply detecting particles, particle detection is normally performed by picking up the diffusely reflected component of laser light, but with this method, when a wafer with a pattern is used as the object, the pattern is also detected as a particle. Particles on such wafers cannot be detected and measured in this manner because they are picked up.

Therefore, as in this embodiment, a patterned wafer is used as the object to be cleaned.
In this case, particle detection is performed using the polarization characteristics of the laser beam.

The principle of this particle detection will be briefly explained using the schematic diagram shown in FIG. 3 as follows.

For example, as shown by the arrow in FIG. 3(a), the S-polarized laser beam 12a is applied horizontally to the object to be cleaned I (wafer) to be inspected. At this time, the reflected light 12b from the pattern 10' perpendicular to the illumination light does not change its polarization and advances to the objective lens 15 as S-polarized light.

The analysis axis of the analyzer 16a is arranged perpendicular to the polarization of this reflected light, and the reflected light is extinguished and does not reach the detector 16, and is angled at an angle relative to the illumination light as shown in FIG. 3(b). The reflected light 12c from the pattern 10# having
5 and does not affect detection.

On the other hand, FIG. 3(C) shows a case where the illumination light 12a hits the foreign object 10. In this case, the polarization of the laser changes and it comes to include P-polarized light due to a kind of depolarization phenomenon. Since this passes through the analyzer 16a, the detector 6 can detect the foreign matter.

An example of a configuration in which a detection means is specifically assembled using this is shown in FIG.

For example, the laser irradiation system can be composed of a He-Ne laser 13a and a beam expander 13b. In order to detect foreign matter, the wafer, which is the object to be cleaned 1, is made movable in four directions in the XY force direction and in the angle θ direction. This provides laser spot illumination to the detection point.

The detection system includes an objective lens 15, a slit eye 6b, and an analyzer 16.
a. It can be composed of a photomultiplier tube, etc.

Regarding such particle detection means, other
Kindai Editorial Company [Surface Control & Cleaning Design J 1
You can refer to Koizumi's ``Inspection equipment for foreign matter on semiconductor wafers and its utilization J'' published in NCL43, page 54 onwards, in the fall of 9B9.

Next, a focused ion beam (FIB) device, which is an example of a means for removing particles by energy irradiation that can be used in this embodiment, will be described.

For example, as schematically shown in FIG.
Accordingly, particle removal can be achieved by irradiating the particles 10 on the object to be cleaned 1 (wafer) with the ion beam one by one based on the position information stored in advance.

In FIG. 5, 3' is a gas gun for using etching gas as required.

〔Effect of the invention〕

As described above, according to the present invention, particles on the object to be cleaned can be reliably and completely removed one by one,
Therefore, when used for cleaning semiconductor wafers, wafers can be obtained with high reliability.

2 is a block diagram showing an example of the structure of the particle removal device of the present invention, FIG. 3 is an explanatory diagram of the principle of particle detection using polarized light, and FIG. 4 is a particle detection means FIG. 5 is a block diagram showing a specific example of the structure of an ion beam irradiation device, which is a particle removing means.

I...Particle detection, ■...Particle position memory, ■...Particle removal.

DESCRIPTION OF SYMBOLS 1... Object to be cleaned (wafer), 10... Particles, 2... Memory section, 20... Control section.

Claims (1)

[Claims] 1. Detect particles existing on the object to be cleaned one by one, store each position of each detected particle, and detect each particle one by one for each stored position. A method for removing particles from an object to be cleaned, the method comprising removing particles. 2. Particle detection means for detecting particles present on the object to be cleaned one by one, a control section having at least a storage section for storing each position of each detected particle, and a control section for detecting particles by energy irradiation. 1. An apparatus for removing particles from an object to be cleaned, comprising a particle removing means for removing particles one by one.