RU2827317C1 - Device for washing and drying round semiconductor substrate and removing drops from its surface - Google Patents

Abstract

FIELD: various technological processes.

SUBSTANCE: invention can be used for deep high-quality cleaning of surface in production of IC, LSI and VLSI. Essence of the invention consists in the fact that a device for washing and drying a round semiconductor substrate and removing drops from its surface with a Marangoni effect comprises a bath for washing substrates and a drying chamber, as well as a substrate carrier attached to the vertical movement mechanism with acute-angled projections with recesses for holding the substrate, each of which has a channel creating a rarefaction in the zone of contacts of the substrate and the carrier, having a diameter greater than the thickness of the processed substrate, but less than the base of the protrusions, which changes into a channel of a larger diameter, wherein substrate carrier is composed of housing with concave top surface while number of acute-angled projections with channels is at least five.

EFFECT: providing the possibility of improving the quality of processing a round semiconductor substrate.

3 cl, 9 dwg

Description

The invention relates to devices for cleaning and drying the surface of products, primarily semiconductor substrates, and is intended for use in the design of equipment for individual chemical treatment of substrates and can be used in the electronics industry for deep, high-quality surface cleaning in production during the manufacture of integrated circuits, large-scale integrated circuits and large-scale integrated circuits.

A multi-point holder used in a method and apparatus for drying substrates is known, described in patent US 5884640 A (Method and apparatus for drying substrates), 07.08.1997.

The multi-point holder is used in the drying process of the Marangoni effect substrate to fix it in a vertical position at different holding points, while the liquid surface level is lowered relative to the substrate, so that the residual liquid flows off the substrate surface without crossing the lowered liquid surface level with the holding points on the substrate.

The known device contains:

- holding surfaces for holding the substrate at various points;

- a control system for actuating and monitoring the operation of the holding surfaces and their holding position on the substrate.

The disadvantage of the device is that the substrate is fixed on the holding surfaces, which leads to the formation of streaks on the substrate at the points of contact of these surfaces with the substrate.

A device for attaching a substrate is also known, described in patent US 2016201986 A1 (Substrate holder assembly, apparatus, and methods), 01/09/2015.

The device for holding the substrate is configured and adapted to hold the substrate in a vertical position during its cleaning and drying with the Marangoni effect. At the same time, a vacuum is created along the lower edge of the substrate in one or more places to remove liquid.

This device includes:

- a frame having a plurality of supports for contact with the substrate, configured to contact the substrate and support it;

- one or more vacuum ports configured to supply vacuum at one or more locations along the bottom edge of the substrate.

The disadvantages of the known device are the complexity of the design and the increased cost of the equipment.

This drawback is due to the presence of a residual moisture removal control system, which includes a vacuum pump, pipeline supply and a vacuum on/off valve.

The set of features closest to the set of essential features of the claimed technical solution is inherent in the known device described in patent RU 2510098 C1 “Method and device for washing and drying substrates” H01L 21/306, 27.07.2012, adopted as a prototype.

Fig. 1-2 shows a view of a prototype device holding a substrate.

The prototype device comprises a substrate wash bath including the necessary equipment, namely a supply and drain line for deionized water, two tubes installed on both sides of the processed substrate in the area of its exit from the deionized water into the drying chamber, each of which contains a number of openings for feeding an organic solvent to the interface between the level of the deionized water of the wash bath and the air environment of the drying chamber, connected by a supply line for the vapors of the organic solvent, as well as a megasonic emitter mounted motionless on the wall of the bath. In addition, a substrate carrier with acute-angled protrusions with recesses for holding the substrate, each of which has a channel creating a vacuum in the contact area of the substrate and the carrier, having a diameter greater than the thickness of the processed substrate, but less than the base of the protrusions, passing into a channel of a larger diameter. The substrate carrier attached to the vertical movement mechanism is designed for washing and drying rectangular substrates with Marangoni effect, such as glass substrates for liquid crystal displays.

Two strips 17, 18 with acute-angled projections 2, in the recesses 3 of which the substrate 6 is installed with its lower 15 and lateral 16 ends, each acute-angled projection 2 in turn contains a channel of smaller diameter 4, creating a vacuum, with a diameter greater than the thickness of the processed substrate, but smaller than the base of the projections, which in turn pass into channels of larger diameter 5, a holder 19 in the form of a square.

The prototype device operates as follows (Fig. 3-4):

The substrate 6 to be processed is installed with its lower 15 and side 16 ends on the recesses 3 in each acute-angled projection 2 of the strips 17, 18. The strips 17 and 18 are installed on the holder 19 in the form of a square.

The substrate installed on the prototype device by means of the vertical movement mechanism 9 is lowered into the bath 8 for washing with deionized water until the substrate 6 is completely immersed, then the substrate 6 is slowly lifted out of the water into the drying chamber, and at the moment the substrate exits the water, vapors of an organic solvent are supplied to the interface of the level of the deionized water of the bath 8 and the air environment of the chamber, and dried. Channels of smaller diameter 4, provided in the acute-angled projections 2 of the strips 17, 18, passing into channels of larger diameter 5, create a vacuum in the contact zone of the substrate and the carrier due to the pressure difference in them when the substrate 6 is lifted, facilitating the removal of the remaining water from the contact zones.

The disadvantage of the prototype device is its design, which does not allow the installation of a round substrate.

This drawback is due to the fact that when a round substrate is installed on the device, not all of the sharp-angled protrusions will touch the edge of the substrate, therefore, the round substrate will not be securely fixed and may be damaged during processing.

The task that the proposed device is aimed at solving is to improve the quality of processing a round semiconductor substrate during its washing and drying.

In order to solve the stated problem, in a device for washing and drying a semiconductor substrate and removing drops from its surface with the Marangoni effect, containing a bath for washing substrates and a drying chamber, as well as a substrate carrier attached to a vertical movement mechanism with acute-angled protrusions with recesses for holding the substrate, each of which has a channel that creates a vacuum in the contact zone of the substrate and the carrier, having a diameter greater than the thickness of the processed substrate, but less than the base of the protrusions, passing into a channel of a larger diameter, according to the invention, the carrier is a housing for holding the substrate, the upper surface of which is made concave, and the number of acute-angled protrusions with channels is at least equal to five.

The proposed device solves the problem of removing residual drops from this substrate without forming streaks, as well as without forming contaminants or liquid residues on the substrate.

When cleaning and drying semiconductor substrates using the Marangoni effect, the substrate is lowered by a vertical movement mechanism into a bath with deionized water, on the surface of which a zone is created, for example, from a mixture of isopropanol vapor and nitrogen. Deionized water is pumped out of the bath at a certain speed, and the substrate is stationary on the carrier body. As the water decreases, the substrate passes through the phase boundary vertically, i.e. perpendicular to the liquid surface, the boundary between the gas medium (isopropanol vapor with nitrogen) and deionized water. Due to the difference in the surface tension of isopropanol and water, a surface layer is created on the surface of the water, consisting of isopropanol absorbed by the surface layer of water. The formation of such a layer, determined by the surface tension forces of two liquid media, isopropanol and water, is characterized by the Marangoni effect. At the point where the substrate emerges from the liquid, a meniscus is formed, and in the upper part of the meniscus, the concentration of isopropanol absorbed by the water surface is significantly greater than in the lower part of the meniscus, due to which the surface tension coefficient in the upper part of the meniscus differs sharply from the surface tension coefficient in the lower part of the meniscus, which leads to the cleaning of the substrate surface and its drying.

After the substrate has completely exited the water, in order to eliminate water droplets retained in the contact area of the substrate with the device, created by surface tension forces, channels are provided in the device body. The substrate is retained on the carrier body along the lower arc with the help of five acute-angled protrusions having channels with a diameter greater than the thickness of the processed substrate, but smaller than the base of the protrusions, which in turn pass into channels of a larger diameter. It is five or more acute-angled protrusions with channels that make it possible to completely extract moisture droplets formed at the point of contact of the lower arc of the substrate with the device. The effect of removing droplets consists in the property of the occurrence of a vacuum in the channel of a larger diameter as deionized water is removed. Thus, a drop of water retained in the contact area of the substrate and the device is pumped out of the channel.

Polyacetal or fluoroplastic is proposed as a material for manufacturing the claimed device, since these materials do not react with any organic and inorganic substances (acids, alkalis, alcohols) and do not introduce additional contamination into the washing and drying process. The cast structure of the carrier body contains at least five acute-angled protrusions and has no seams, pores or burrs, which allows the round semiconductor substrate to be securely fixed, minimally contacting the carrier body. Thus, in addition to improving the quality of processing, the risk of damaging the semiconductor substrate during processing is minimized.

The essence of the claimed device is explained by drawings.

Fig. 5 is a view of the carrier body holding the substrate;

Fig. 6 is a projection view of the carrier body;

Fig. 7 shows the processing of the substrate during the drying process;

Fig. 8 shows the formation of a drop at the point of contact between the substrate and the device;

Fig. 9 shows the removal of liquid from the channel when the substrate exits the cleaning bath.

In Fig. 5-9 the following notations are used:

1 - carrier body (carrier);

2 - acute-angled protrusions;

3 - recesses for holding the substrate;

4 - channels of smaller diameter;

5 - larger diameter channels;

6 - a substrate held by the device;

7 - drop at the point of contact between the substrate and the device;

8 - bath;

9 - vertical movement mechanism;

10 - damper;

11- isopropyl alcohol supply channel;

12- nozzles;

13 - deionized water supply channel;

14 - channel for pumping out deionized water;

The proposed device contains (Fig. 5, 6) a cast carrier body 1, in the upper part of which there are five acute-angled projections 2 with recesses 3 for holding the substrate, at the top of each acute-angled projection 2 there is a channel of smaller diameter 4, the diameter of which is greater than the thickness of the processed substrate 6, but less than the base of the projections 2. Then each channel of smaller diameter 4 passes into a channel of larger diameter 5 to create a vacuum at each point of contact of the substrate 6 and the carrier body 1.

The claimed device operates as follows (Fig. 5-9).

The substrate 6 is installed in the body of the carrier 1 and, using the vertical movement mechanism 9, is lowered into the bath 8 filled with deionized water (Fig. 7). The valve 10 of the bath 8 is closed and isopropyl alcohol vapors are supplied through the channel 11, which are uniformly sprayed by the nozzles 12. The supply of deionized water through the channel 13 is stopped, and its pumping out begins through the channel 14. As the water level decreases, the internal cavity of the bath 8 is filled with alcohol vapors, thereby creating a meniscus at the point where the substrate 6 exits the liquid, while in the upper part of the meniscus the concentration of isopropanol absorbed by the water surface is significantly greater than in the lower part of the meniscus, due to which the surface tension coefficient in the upper part of the meniscus differs sharply from the surface tension coefficient in the lower part of the meniscus, which leads to the cleaning of the surface of the substrate 6 and its drying.

The substrate 6 is held along the upper concave part of the carrier body 1 with the help of recesses 3 in five acute-angled projections 2 having channels of smaller diameter 4, passing into channels of larger diameter 5 (Fig. 5). The droplet removal effect (Fig. 8, 9) consists in the property of the occurrence of a vacuum in the channels of large diameter 5 as deionized water is removed. Thus, a drop of water 7, held in the contact zone of the substrate 6 with the carrier body 1, is pumped out of the channel of larger diameter 5 and removed.

The technical result is an improvement in the quality of processing a round semiconductor substrate.

Claims (3)

1. A device for washing and drying a round semiconductor substrate and removing droplets from its surface with the Marangoni effect, comprising a bath for washing substrates and a drying chamber, as well as a substrate carrier attached to a vertical movement mechanism with acute-angled protrusions with recesses for holding the substrate, each of which has a channel that creates a vacuum in the contact zone of the substrate and the carrier, having a diameter greater than the thickness of the substrate being processed, but less than the base of the protrusions, passing into a channel of a larger diameter, characterized in that the substrate carrier is a housing for holding it, the upper surface of which is made concave, and the number of acute-angled protrusions with channels is at least equal to five. 2. The device according to item 1, characterized in that the carrier body is made of polyacetal. 3. The device according to item 1, characterized in that the carrier body is made of fluoroplastic.

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