JPH01207182A - Cleaning liquid for substrate surface - Google Patents

Abstract

PURPOSE:To efficiently clean and remove superfine contaminating particles, etc., and to eliminate problems such as generation of static electricity and flawing of a substrate by injecting fine frozen particles toward the substrate. CONSTITUTION:The frozen particle produced by a frozen particle producing means 20 are injected by an injecting means 7 toward the substrate 1 held by a holding means 40. The contaminants are dissolved by a solvent while the fine contaminating particles and dirt on the substrate 1 are blown off by the impact of the fine frozen particles. As a result, an excellent cleaning effect is obtd. and since a cleaning brush is not used at all unlike in the conventional manner, the problem such as contamination by the wear of the brush and the degraded cleaning efficiency by generation of the static electricity generated from the friction of the electrostatically chargeable brush are solved.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a cleaning device for the surface of a substrate, and in particular, it cleans deposits on the substrate by spraying fine frozen particles toward the substrate. The present invention relates to a cleaning device for cleaning the surface of a substrate.

[Prior Art] FIG. 3 schematically shows a conventional semiconductor wafer cleaning method. In the figure, 1 is a semiconductor wafer. 2 is a jet nozzle that sprays ultrapure water onto the surface of the semiconductor wafer 1. 3 is a brush that slides on the surface of the semiconductor wafer 1. Next, a conventional semiconductor wafer cleaning method will be described with reference to this figure.

Ultrapure water is sprayed onto the surface of a semiconductor wafer 1 using a jet nozzle 2. At the same time, the brush 3 rotating in the direction of arrow R is slid onto the surface of semiconductor wafer 1 in the direction of arrow T. As a result, contaminant particles and the like adhere to the surface of the semiconductor wafer 1.The conventional semiconductor wafer cleaning method is configured as described above. However, ■about 10μ
It is difficult to clean and remove ultra-fine contaminant particles with a size of less than 100 yen (m), and ■ abrasion of the cleaning brush may cause contamination of the semiconductor wafer; and ■ static electricity is generated due to brush friction, reducing cleaning effectiveness. There was a problem that (1) the removed foreign matter adhered to the cleaning brush, and this foreign matter could damage the semiconductor wafer.

This invention was made in order to solve the above-mentioned problems, and can effectively remove ultra-fine contaminant particles by cleaning, as well as reduce contamination caused by brush wear and static electricity caused by brush friction. This invention provides a cleaning device for the surface of a substrate that can eliminate problems such as generation and damage to substrates such as semiconductor wafers.This invention removes deposits on the substrate by spraying fine frozen particles toward the substrate. do,
This relates to a cleaning device for the surface of a substrate. In order to solve the above problems, the following members are provided.

(1) Frozen particle production means for producing fine frozen particles.

(2) Holding means for holding the substrate.

(3) Spraying means for jetting the frozen particles manufactured by the frozen particle manufacturing means toward the substrate held by the holding means.

In a preferred embodiment of the substrate surface cleaning apparatus according to the present invention, the holding means is configured to hold the substrate such that the injection angle of the frozen particles is 30° or less with respect to the substrate. ing.

[Operation] The substrate surface cleaning device according to the present invention has the above means (1).
, (2), and (3), the frozen particles sprayed toward the substrate blow off and remove contaminants and other deposits on the substrate.

Additionally, the liquid that results from the melting of frozen particles acts as a solvent for the contaminants.

Further, in a preferred embodiment of the present invention, the holding means is configured to hold the substrate such that the injection angle of the frozen particles is 30° or less with respect to the substrate, so that the substrate is You can't take damage.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a first embodiment of the invention.

The substrate surface cleaning device according to the embodiment basically includes a frozen particle manufacturing means 20 for manufacturing fine frozen particles, and a holding means 40 for holding a substrate, such as a semiconductor wafer.
and a spraying means 7, such as a spray nozzle, for spraying the frozen particles produced by the frozen particle producing means 20 towards the substrate 1 held by the holding means 40.

First, the configuration of the frozen particle manufacturing means 20 will be explained in detail.

A heat insulating container 4, which is a component of the frozen particle production means 20, is provided with a spray nozzle 5.

The heat insulating container 4 is divided by a mesh 4a. The heat insulating container 4 is provided with a refrigerant supply port 6 for supplying a refrigerant into the heat insulating container 4 . A liquid to be frozen 1, such as ultrapure water, to be frozen in the heat insulating container 4 is stored in a raw material liquid storage tank 8. The raw material liquid storage tank 8 has a raw material liquid supply port 8.
A is provided, and the liquid to be frozen is supplied from this raw liquid supply port 8a.

The liquid to be frozen 12 is then sent to the spray nozzle 5 through the pipe line 85.

The injection means 7 are embodied, for example, by an injection nozzle. Frozen particles 12a produced by the above-mentioned frozen particle production means are sent to this injection means 7.

Next, regarding the holding means 40 for holding the substrate 1,
Its configuration will be explained in detail.

The holding means 40 includes a fixing jig 9 and a vacuum pump 10. Fixture jig 9 rotates in the direction indicated by arrow A. Further, the fixing jig 9 moves in the direction indicated by arrow B. The substrate 1 is fixed to the fixing jig 9 by the suction force of the vacuum pump 10. The substrate 1 is fixed to the fixing jig 9 so as to be parallel to the injection direction of the frozen particles ejected from the injection means 7 (in this case, the injection angle with respect to the substrate 1 is 0).

Next, the operation of cleaning the surface of the substrate 1 using the cleaning apparatus according to the embodiment will be described.

The inside of the raw material liquid storage tank 8 is pressurized with gaseous nitrogen. Due to this pressurization, the liquid to be frozen 12 is sent to the spray nozzle 5 through the pipe line 85. The liquid to be frozen 12 that has been sent to the spray nozzle 5 is sprayed into the heat insulating container 4 by the pressure of gaseous nitrogen. At this time, the inside of the heat insulating container 4 is cooled by a refrigerant such as liquid nitrogen supplied from the refrigerant supply port 6. Therefore, the liquid to be frozen sprayed from the spray nozzle 5 becomes fine frozen particles 12a, falls on the mesh 4a, and accumulates thereon. Note that the liquid to be frozen may be a substance that does not adversely affect the semiconductor wafer, such as ultrapure water, alcohols such as ethanol, or fluorocarbon-based solvents. Furthermore, the size of the sprayed droplets is determined by the pressure of the spray 5 and the amount of gaseous nitrogen.

The frozen particles 12a produced as described above are sent to the injection means 7, and are injected toward the substrate 1 by an ejector method using a jet of gaseous nitrogen.

On the other hand, the fixing jig 9 simultaneously injects the frozen particles 12a.
It moves in the direction of arrow B while rotating in the direction of arrow A. Therefore, the foreign matter on the substrate 1 is blown off and removed by the force applied in the lateral direction by the frozen particles 12a. At this time, the liquid resulting from the melting of the frozen particles acts as a solvent for foreign substances, so that the surface of the substrate 1 is cleaned even more beautifully. Further, the injection direction of the frozen particles 12a is set to the substrate 1.
Since the frozen particles do not collide with the surface of the substrate 1, the substrate 1 is not damaged.

FIG. 2 is a schematic diagram of frozen particle manufacturing means constituting another embodiment of the present invention. In addition, in FIG. 2, only the frozen particle manufacturing means 20 is illustrated, and illustration of the holding means 40 and the injection means 7, which have the same configuration as FIG. 1, is omitted. In the above embodiment, since the liquid to be frozen 12 was supplied to the spray nozzle 5 in a liquid state, only frozen particles with a size of 10 μm or more were obtained. The embodiment shown in FIG. 2 shows the configuration of a frozen particle manufacturing means that can supply ultrafine frozen particles of 20 μm or less. In the figure, reference numeral 11 denotes a closed container, and a liquid to be frozen 1, such as ultrapure water, is placed inside the closed container 11.

13 is a heating means for heating the closed container 11 from the outside.

The closed container 11 is connected to a cooling container 14. The cooling container 14 is similar to the insulating container 4 of the previous embodiment.

Next, the operation will be explained. A liquid to be frozen 12 placed in a closed container 11 is heated by a heating means 13 and turned into steam. This vaporized liquid to be frozen is rapidly poured into a sufficiently cooled cooling container 14.

This causes condensation of the steam, and the condensed steam freezes into frozen particles. In this frozen particle manufacturing means, the size of the frozen particles can be changed by changing the rate of condensation of vapor (that is, changing the temperature of the cooling container 14). Then, ultrafine frozen particles of 20 μm or less are obtained. These ultra-fine frozen particles are
The spraying means 7 as shown in the figure sprays toward the substrate 1 arranged as shown in FIG. Then, the jetted frozen particles scrape off foreign matter on the substrate 1.

Furthermore, as described above, the solution in which the frozen particles are dissolved acts as a solvent for contaminants, thereby cleaning the substrate 1 more beautifully.

Next, in the above-described embodiment, the holding means 40 holds the substrate so that the injection direction of the frozen particles is parallel to the substrate 1, if the substrate is perpendicular to the smooth surface of the semiconductor wafer. This is because, if frozen particles are injected, the frozen particles may damage the semiconductor wafer pattern or thin oxide film, and the effect of pushing away foreign matter on the semiconductor wafer will be reduced. In the above embodiment, the case where the substrate 1 is held by the holding means 40 so that the injection direction of the frozen particles is parallel to the substrate 1 (that is, the injection angle is 0) has been described. However, the present invention is not limited to this, and it is preferable to appropriately adjust the injection angle of frozen particles within a range of 30° according to each individual case. For example, in order to remove foreign matter on a fine pattern or very fine foreign matter of about 0.5 μm or less, it is better to spray at an angle because the foreign matter has a strong adhesion force. Parallel to the smooth surface of the wafer is sufficient for removing large foreign particles. However, if the spray angle is larger than 30°, the substrate surface will be damaged, which is not preferable.

Further, in the above embodiment, the case where a semiconductor wafer is used as the substrate 1 has been described, but the present invention is not limited to this, and the invention is not limited to this. Even if applied, the same effect as the above embodiment can be achieved.

Further, in the above embodiments, a case has been described in which pure water is used as the liquid to be frozen, but the present invention is not limited to this.

Although the cleaning device of the present invention has been described above with reference to specific embodiments, the present invention can be implemented in various other forms without departing from its spirit or main characteristics. Therefore, the above-described embodiments are merely illustrative in all respects and should not be construed as limiting. The scope of the present invention is indicated by the claims, and is not restricted in any way by the main text of the specification. Furthermore, all modifications and changes that come within the scope of equivalents of the claims are intended to be within the scope of the present invention.

[Effects of the Invention] As explained above, according to the substrate surface cleaning device according to the present invention, fine contaminant particles and dirt on the substrate are blown away by the impact of fine frozen particles, while contamination by the dissolved solvent is removed. Since it dissolves substances, excellent cleaning effects can be obtained. Furthermore, since no cleaning brush is used as in the prior art, problems such as contamination due to wear of the brush and deterioration of cleaning effectiveness due to generation of static electricity caused by friction of the charged brush can be solved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of one embodiment of the present invention, FIG. 2 is a schematic diagram of another embodiment of the invention, and FIG. 3 is a schematic diagram showing a conventional semiconductor wafer cleaning method. In the figure, 1 is a substrate, 4 is a heat insulating container, 4a is a mesh, 5 is a spray nozzle, 6 is a refrigerant supply port, 7 is an injection nozzle, 8 is a raw material liquid storage tank, 8a is a raw material liquid supply port, and 9 is a fixed fixture. 10 is a vacuum pump, 12 is a liquid to be frozen, 12a
20 is a frozen particle, 20 is a frozen particle manufacturing means, and 40 is a holding means. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A substrate surface cleaning device that removes deposits on a substrate by spraying fine frozen particles toward the substrate, comprising a frozen particle manufacturing means for manufacturing fine frozen particles. a holding means for holding the substrate; and a spraying means for spraying frozen particles produced by the frozen particle producing means towards the substrate held by the holding means. cleaning equipment.