JPS60198721A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the generation of a crack by coating the surface of an silicon wafer with a resist film, removing the resist films in a section, to which ions are to be implanted, and the section of a scribing line, and implanting ions thereinto. CONSTITUTION:A resist film 11 is formed on the surface of an silicon wafer 10. The resist films in chip scribing line sections for each chip are removed through patterning even in the surfaces of the resist films while being made to correspond to borderline sections among opening windows 12, from which ions must be implanted to the resist films 11, and a large number of chips 13 formed to the silicon wafer, the chip scribing line sections, and the surfaces of the resist films are isolated insularly. Accordingly, ions are implanted to the surface of the silicon wafer. Ions are implanted and the resist films are removed, the wafer is annealed, and an ion-implanted impurity is diffused into the silicon wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and particularly to prevention of cranking of a resist film that occurs during ion implantation into the surface of a silicon wafer.

(bl Technology Background In recent years, in the manufacturing process of semiconductor devices, silicon wafers are
A method of implanting impurities by ion implantation is widely used.

The ion implantation method allows impurity introduction with extremely high precision, and the reason for this is that ion implantation can be performed while counting the number of impurity ions during ion implantation.

Therefore, the number of ions to be implanted can be controlled as the integral value of the current, and the penetration depth of impurities implanted into the silicon wafer surface is determined by the ion implantation acceleration voltage, which has many advantages. be.

A basic feature of ion implantation is that it is possible to mask the silicon wafer surface.

By using a mask material that is sufficiently thicker than the flying distance of the implanted ions to form the mask, the implanted ions stop inside the mask material and do not reach the silicon wafer surface.

However, in this ion implantation, the photoresist material can be used as is as a masking material, so the manufacturing process of semiconductor devices that combines this resist film and ion implantation method is possible because the ion implantation area is localized. Even if the temperature rises, the temperature of the surrounding area does not rise, making it extremely important for achieving low temperature processes in the manufacturing of semiconductor devices.

However, in the manufacturing process of semiconductor integrated circuits in which a large number of chips are formed on the surface of a silicon wafer, a resist film is formed on the surface of the silicon wafer, and then an opening window into which a large number of ions are to be implanted is formed by patterning.
Ions will be implanted into that part, but the surface of the silicon wafer where the ions will be implanted will be localized.
The temperature rises rapidly, and the temperature does not rise on the silicon wafer surface where the resist film remains, so the resist film on the silicon wafer surface is distorted due to the temperature difference. There is a problem that cranks occur in the film, and if ion implantation is performed with a resist film that has cranks, ions will be implanted into the crank portions, and there is a need for an improvement in this problem.

(C) Prior Art and Problems FIG. 1 is a diagram illustrating the state of a resist film coated on the surface of a silicon wafer in a conventional method.

First, a resist film 2 is formed on the surface of a silicon wafer 1 to shield implanted ions.

As the resist film, a commonly used photoresist material can be used as is, and the entire surface of the silicon wafer is coated.

Generally, a resist film is created by attaching a silicon wafer to a spinner that rotates at high speed, and
A film having a uniform thickness is formed by dropping a resist solution.

The thickness of silicon wafer is usually 0.3mm to 0.5mm.
The diameter is about 3 inches to 4 inches, and the thickness of the resist film coated on the surface of the silicon wafer is about 1 μm.

Open windows 3 are formed by removing portions of the resist film where ions are to be implanted using a normal patterning method.

Since a large number of chips 4 are arranged on the silicon wafer surface, a numerical aperture corresponding to the number of chips is required.

Next, ions are implanted into this opening, but due to the diffusion of the implanted ion beam, the ion beam may collide with the resist film around the opening, causing the resist film to heat up. The silicon wafer surface may be uneven due to differences in temperature on the silicon wafer surface or local temperature differences in the resist film due to the difference between the areas on the silicon wafer surface where the ion beam is projected and the areas where it is not. A crank 5 occurs due to the difference in expansion in the resist film.

If a crank occurs in the resist film in this way, it becomes impossible to implant ions into the silicon wafer surface at an accurate position, and there is a drawback that ions may be implanted into unnecessary parts of the silicon wafer. Ta.

(dl Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention provides the following advantages:
It is an object of the present invention to provide a manufacturing method that prevents a resist film formed on the surface of a silicon wafer from producing cranks caused by a sudden local temperature rise.

(e) Structure of the Invention According to the present invention, after a resist film is coated on the surface of a silicon wafer, the resist film in the ion implantation area and the scribe line area is removed in advance, and then the ion implantation is performed. This can be achieved by providing a method for manufacturing a semiconductor device that includes a step of implanting.

(f) Embodiment of the Invention FIG. 2 is a diagram illustrating the structure of a resist film when ions are implanted into the surface of a silicon wafer according to the present invention.

In the figure, 10 is a silicon wafer, and a resist film 11 having a thickness of about 1 μm is formed on the surface of the silicon wafer by the spinner method described above.

Next, this resist film is patterned to correspond to the boundary line between the opening window 12 where ions are to be implanted and the large number of chips 13 formed on the silicon wafer, that is, the chip scribe line portion. Then, the resist film surface is also patterned to remove the resist film at the chip scribe line portion of each chip and separate it into islands.

To explain a specific example, it is assumed that the diameter of a silicon wafer is 3 inches, and a large number of square chips of 5 mm x 5 mm are formed on the surface of this silicon wafer.

It is assumed that each chip 7 has a portion to be implanted with ions, and the shape of the opening window 12 is 4 μm.
XIQ/! Suppose that it is a rectangle of m.

In this case, the patterning of the resist film on the silicon wafer surface was such that the above ion-implanted area was patterned to the size of the shape, and the resist film was removed in correspondence with the chip scribe line between the chimneys. The groove width of the separation groove 14 is about 90 μm, so that the resist film between each chip is separated in the shape of a base grain.

In this way, ions are implanted into the surface of the silicon wafer. For example, ions such as phosphorus (P) are implanted to form an N-type silicon wafer.

At this time, the temperature of the opening window on the surface of the silicon wafer where ions are implanted rapidly rises due to the energy of the ions, and the surface of the conventional resist film is distorted due to the wooden area coded over the entire surface of the silicon wafer. However, since the resist film of the method of the present invention is separated into small island-shaped areas, even if distortion occurs, the distortion is absorbed by the small island-shaped areas, and the resist film No cranking occurs in the membrane.

After the ion implantation is completed, the resist film is removed and the wafer is annealed to diffuse the implanted impurities into the silicon wafer, completing the wafer ion implantation fabrication process.

(gl Effects of the Invention As explained in detail above, by adopting the present invention in the manufacturing process of semiconductor devices, ions can be accurately implanted into the surface of a silicon wafer, and high-quality semiconductor devices can be manufactured. There is something big.

[Brief explanation of drawings]

FIG. 1 shows a resist film of the conventional ion implantation method, and FIG. 2 shows a resist film of the ion implantation method of the present invention. In the figure, 1.10 is a silicon wafer, 2.11 is a resist film, 3.12 is an opening window, 4.13 is a chip, and 5
14 is a crank, and 14 is a separation groove in the resist film. Figure 7 Second leap

Claims (1)

[Claims] 1. A method for manufacturing a semiconductor device, comprising the step of coating a silicon wafer surface with a resist film, removing the resist film in the ion-implanted area and the scribe line area in advance, and then implanting the ions.