JPS63110639A - Manufacture of integrated circuit device - Google Patents

Abstract

PURPOSE:To contrive to remove dust of a submicron level without breaking transistors constituting an integrated circuit by a method wherein pure water containing nonmetallic ions is turned into a jet water current by a pressing unit and a jet nozzle while a wafer is rotated and the jet current is sprayed on the surface of the substrate to clean the surface. CONSTITUTION:Ultrapure water (a) manufactured by an ultrapure water manufacturing unit 1 is transported to a pressing unit 3 through a first piping 2. A branch 4 is provided in the midst of the first piping 2 and this branch 4 is connected to a CO2 container 6, which is used as a non-metallic ion source encapsulated by pressing, through a pressing control valve (pressure control valve) 5. The non-metallic ion-containing ultrapure water pressed by the pressing unit 3 passes through a second piping 7, is transported to a jet nozzle 8 and is jetted through the point of the jet nozzle 8 as a jet water current 10. On the other hand, a wafer 21 with its surface to be cleansed is fixed on the rotating stand 22 by a method of vacuum attraction and so on and the wafer 21 is also rotated by this rotating stand 22. Accordingly, the jet water current 10 is sprayed almost uniformly on the surface of the rotating wafer 21.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of Industrial Application 1. The present invention relates to a method for manufacturing an integrated circuit device, and in particular to a process (hereinafter referred to as a wafer) of forming an integrated circuit device on the main surface of a semiconductor substrate (hereinafter referred to as a wafer). The present invention relates to a method for manufacturing an integrated circuit device that requires a large cleaning process for the wafer surface in 10 wafer processes.

1 Conventional technology! In recent years, the dimensions of transistors and the like forming an integrated circuit device have continued to decrease, and the number of transistors integrated into an integrated circuit device has continued to increase. In recent years, some integrated circuit devices with a minimum size of 171 rrl or less and a transistor count of 300,000 or more have appeared.

In manufacturing integrated circuits with such minute dimensions and scale,
Removal of dirt adhering to the wafer surface is a significant concern. In fact, in a standard process of 10 wafers, the wafer surface is cleaned more than 15 times.

Specific methods for cleaning the wafer surface in conventional wafer processes include methods using pure water immersion and ultrasonic waves, immersion in ammonia or hydrogen peroxide mixture, thermal FfL acid immersion or hot nitric acid immersion, There are methods such as brushing or jet spraying with only pure water.

[Problem that the invention seeks to solve]

Among the conventional wafer cleaning methods mentioned above, the liquid immersion method was adopted in early wafer processing.
Although it is effective in removing dust with a size of 1 μm or more, it is hardly useful in removing dust with a submicron level that is harmful to integrated circuits constructed with recent reduced dimensions.

In addition, the brushing method is a very atomic method,
It does more damage to the wafer surface than removes dirt, and is equally useless at removing dirt.

Furthermore, the method of jetting pure water and spraying it onto the wafer surface is currently the most effective method for removing submicron level dust adhering to the wafer surface.

However, the pure water used in recent wafer processes requires what is called ultrapure water, in which all dissolved and insoluble impurities, as well as organic and inorganic debris, have been removed to the utmost extent. When such ultrapure water is turned into a jet stream, static electricity is generated due to friction between water molecules, which can momentarily exceed 20,000 volts. On the other hand, reducing the dimensions of an I-transistor that constitutes an integrated circuit in a three-dimensional direction inevitably requires scaling down in three dimensions according to the proportional reduction law.
The thickness of a normal Si thermal oxide film is 100 to 200. However, the dielectric breakdown limit of 5i02 is 8 M
Since the voltage is about V/c1, the dielectric breakdown voltage of the gate insulating layer having the above-mentioned thickness is at most 8 to 16V. Therefore, if ultrapure water is jetted and sprayed onto the wafer surface, it is possible to remove submicron-level dust, but
There is a problem in that the instantaneous voltage can destroy the transistors that make up the integrated circuit.

An object of the present invention is to provide a method for manufacturing an integrated circuit device that effectively removes submicron-level dust without causing damage to the transistors constituting the integrated circuit when cleaning the wafer surface in the above-mentioned wafer process. It is in.

Means for Solving Problems] In the method for manufacturing an integrated circuit device of the present invention, pure water containing non-metal ions is jetted by a pressurizing device and a jet nozzle while rotating a wafer, and is sprayed onto the surface of the substrate. Spraying consists of a step of cleaning the surface.

The reason why nonmetallic ions are added to the ultrapure water is that many of the various metal ions remain on the wafer and act as impurities, impairing the functionality of integrated circuits.

1 Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a jet water spray device for explaining a first embodiment of the present invention.

As shown in FIG. 1, ultrapure water produced in a pure water production device 1 is transported to a pressurizing device 3 via a first pipe 2. As shown in FIG.

Further, a branch 4 is provided in the middle of the first pipe 2,
This branch 4 is connected via a pressure control valve to a CO2 container 2S6 which serves as a pressurized and sealed non-metal ion source. The ultrapure water containing non-metal ions pressurized by the above-mentioned pressurizing device 3 is transported to the jet nozzle 8 through the second pipe 7, and is ejected from the tip of the jet nozzle 8 as a jet water stream 10. On the other hand, a wafer 21 whose surface is to be cleaned is fixed to a rotating table 22 by a method such as vacuum suction, and the wafer 21 is also rotated by this rotating table 22. Therefore, the jet water stream 10 is sprayed almost uniformly onto the surface of the rotating wafer 21.

- The amount of non-metal ion source injected onto the surface is made possible by control of the pressure control valve 5.

In addition, the speed at which the turntable 22 actually rotates is 4,000
RPM and pressurize the ultrapure water to 120 kg/C.
112, it is possible to remove dust adhering to the surface of the wafer 21 down to the submicron level.

FIG. 2 is a configuration diagram of a jet injection device for explaining a second embodiment of the present invention. The difference from the first embodiment is that nonmetal ions are supplied as a liquid after the pressurizing device.

As shown in FIG. 2, the ultrapure water produced by the ultrapure water apparatus 1 is transferred to the first pipe 2. It is transported to the second pipe 7 via the first pressurizing device 3. Also, a branch 11 provided in this second pipe 7 and a second pressurizing device 1 connected to this branch 11
2, an NH4OH container 13 serving as a nonmetal ion source is connected.

Thereby, a jet water stream containing non-metal ions is sprayed from the jet nozzle 8 connected to the tip of the wiring 7 onto the wafer surface 21 provided opposite to the jet nozzle 8. That is, since the wafer 21 to be cleaned is fixed to the rotating table 22 by vacuum suction or the like and rotates together with the rotating table, the jet stream 10 of ultrapure water mixed with NH4014 is applied almost uniformly to the surface of the rotating wafer 21. Can be sprayed. In this second embodiment, since the nonmetal ion source added to the ultrapure water is a liquid, it has the advantage that it easily dissolves in the ultrapure water and does not generate bubbles.

[Effects of the Invention] As explained above, the present invention adds non-metal ions (Co in the first embodiment, -1 in the second embodiment) to ultrapure water from which dissolved impurities and suspended matter have been removed to the utmost limit. The resistivity of ultrapure water can be reduced to 20M V / (, one order of magnitude lower than 1m2
By lowering the M V / C to 1 m, it is possible to reduce the static electricity generated by 1↑ friction between water molecules in a jet stream.
The present invention has the effect of providing a method for manufacturing an integrated circuit device that can effectively prevent the destruction of the transistors 1 to 2 constituting the integrated circuit without reducing the ability of the water jet to remove dust from the wafer surface.

In addition, it is necessary to supply the Jet I water stream without rotating the wafer in order to evenly spray the wafer surface, but if the wafer is rotated even after the Jet I water flow has stopped, the centrifugal force will cause the wafer surface to It also has the effect of removing residual pure water and drying it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a gel-water jet spraying device illustrating a first embodiment of the present invention, and FIG. 2 is a block diagram illustrating a second embodiment of the present invention.

Claims (1)

[Claims] A method for manufacturing an integrated circuit device including a step of cleaning the surface of the substrate when forming the integrated circuit device on one main surface of the semiconductor substrate, wherein the semiconductor substrate is rotated and pure water containing non-metal ions is pressurized. A method for manufacturing an integrated circuit device, comprising the step of generating jet water using an apparatus and a jet nozzle, and spraying water onto the surface of the substrate to clean the surface.