JPH0439226B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to integrated circuits such as transistors (hereinafter referred to as
The present invention relates to improvements in the manufacturing method of IC parts (abbreviated as IC parts), and more specifically, to improvements in the photoetching process during the manufacturing process.

[Prior Art] An example of a conventional method for manufacturing IC components is shown in FIG. The figure shows an etching process during the manufacturing process of a transistor. Manufacturing is performed in the order from a to e in the figure.

In the figure, 1 is a substrate made of, for example, silicon Si, and 2 is an oxide film formed on the surface of the substrate 1, which is made of, for example, silicon dioxide (SiO ₂ ). Although not shown in the figure, the oxide film 2 is formed not only on the front surface but also on the back surface of the substrate 1. The oxide film on the back side is used to monitor the thickness of the oxide film on the front side to be removed.

The shaded portions from a to d in the figure are the portions of the oxide film that are removed in each step.

Before step a is performed, oxide films of the same thickness are formed on the front and back surfaces of the substrate 1.

In the step a in the figure, light transmitted through an IC photomask with a pattern corresponding to the distribution shape of the isolation diffusion layer is projected onto the oxide film, and the oxide film is exposed and developed. For example, in positive type development, the surface of the oxide film in the shaded area is exposed, and the other surface is not exposed. Exposure is performed only on the oxide film on the surface.

Thereafter, the oxide films on the front and back surfaces are etched. Oxide films of the same thickness are formed on the front and back surfaces, and when the oxide film on the back surface disappears and the substrate appears, the thickness of the shaded area on the front surface is t.
Since etching has been performed for only a few seconds, this time is set as the end point of etching.

Silicon dioxide forming the oxide film 2 is hydrophilic, and silicon forming the substrate 1 is hydrophobic, so that when the substrate 1 appears, it repels water. Based on this, the end point of etching is detected.

Thereafter, oxidation is performed to recover the oxide film 3 on the scribe line and the oxide film on the back surface to a thickness ta.

Hereinafter, in steps b to d, exposure and development are performed using different IC photomasks, and etching and oxidation are performed in the same manner as in step a to form holes for the base, emitter, and contact. Thereafter, ions are implanted into the substrate 1 to form a diffusion layer, and wiring is performed to form the transistor shown in e.

In e, 4 ₁ , 4 ₂ , and 4 ₃ are the connection points of the collector, base, and emitter, respectively.

[Problem that the invention attempts to solve] However, with this method, a, b, and c in the diagram
The thickness of the oxide film is different between the portions d and d. Moreover,
In the step b, the thickness of the oxide film on the back surface is ta, and in the step d, the thickness of the oxide film on the back surface is t _C
It's getting old. For this reason, in the steps b and d, even if the oxide film on the back surface is removed by etching, the oxide film on portions b and d remains, making it difficult to detect the end point of etching.

The present invention has been made to eliminate the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing IC components that can easily detect the end point of etching.

[Means for Solving the Problems] The present invention involves forming an oxide film of a certain thickness on a substrate, exposing and developing the oxide film using an IC photomask, and etching according to the development. In a method of manufacturing an IC component in which an oxide film is partially removed by etching to create an oxide film with a shape suitable for a desired IC component, the thickness of the oxide film on the scribe line of the substrate and the predetermined etching area of the oxide film are determined. The method is characterized in that the etching thickness is made equal, etching of the predetermined etching region and etching of the oxide film on the scribe line are performed simultaneously, and the end point of etching is detected based on the oxide film on the scribe line. This is a method for manufacturing IC parts.

[Example] Hereinafter, the present invention will be explained using the drawings.

FIG. 1 is a diagram showing an example of the procedure of the method for manufacturing an IC component according to the present invention. Components in FIG. 1 that are the same as in FIG. 2 are given the same reference numerals.

The difference between the method shown in FIG. 1 and the conventional method shown in FIG. 4 is that in the method shown in FIG. is not carried out.

As a result, in the method shown in FIG. 1, the thickness of the oxide film in portions A and B becomes equal in the step b, and the thickness of the oxide film in portions C and D becomes equal in the step d. Therefore, in the steps b and d, when the oxide film 3 on the scriblin is completely removed, the oxide film on the parts B and D is also completely removed at the same time. Therefore, the oxide film 3 on the scribe line can be used to monitor the end point of etching.

A flowchart of such a manufacturing method is shown in FIG.

An oxide film having a thickness of t is formed on the front and back surfaces of the substrate 1.

First, the oxide film is exposed and developed using an IC photomask (referred to as an isolation photo) with a pattern corresponding to the distribution shape of the isolation diffusion layer.

Next, in judgment _X1 , it is determined whether or not there is any water leakage on the back side of the substrate (whether or not the oxide film on the back side has disappeared and a bonded surface has appeared).

If the decision _X1 is NO, the decision _X1 is performed again after etching.

_{If Judgment} Expose and develop the top.

Next, in judgment _X2 , it is determined whether or not there is a water drop on the scribe line (whether or not the oxide film on the scribe line is gone and the substrate is exposed).

If the decision _X2 is NO, the decision _X2 is performed again after etching.

_{If Judgment} Expose and develop the top.

Next, in judgment _X3 , it is determined whether or not there is any water leakage on the back side of the substrate.

If the decision _X3 is NO, the decision _X3 is performed again after etching.

If judgment X ₃ is YES, further thickness t-t _B
Etching is performed to remove only the oxide film. This is because the thickness of the oxide film on the back surface is only _tB , and the oxide film at portion E cannot be completely removed unless etching is performed to further remove the oxide film with a thickness of t- _tB .

Thereafter, an oxide film with a thickness t _C is formed on the front and back surfaces of the substrate, and then exposed and developed using an IC photomask (referred to as a contact hole photo) with a pattern corresponding to the distribution shape of the contact holes.

_Next , in judgment

If the decision _X4 is NO, the decision _X4 is performed again after etching.

If the decision _X3 is YES, the oxide film in the shaded area d is completely removed, and the etching process is completed.

Furthermore, as shown in FIG. 3, the oxide film on the scribe line LX in the _X direction of the wafer W and the oxide film on the scribe line _LY in the Y direction may be used to detect the end point of etching in different processes. good. For example, the end point of etching in the process shown in FIG. _1B is detected using the oxide film on the scribe line LX, and the end point of etching in the process shown in FIG. 1C is detected using the oxide film on the scribe line _LY in the Y direction. You can use it for different purposes.

[Effect] According to the present invention, the thickness of part A (oxide film on the scribe line) and part B in step b are equal;
Furthermore, since the thickness of portion C (oxide film on the scribe line) and portion D in step d are equal, the oxide film on the scribe line can be used to monitor the end point of etching. Thereby, the end point of etching can be easily detected.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of the steps of the method for manufacturing IC components according to the present invention, Fig. 2 is a flowchart for explaining the manufacturing method of Fig. 1, and Fig. 3 is a scribe formed on a wafer. Diagram showing lines, 4th
The figure shows a conventional example of a method for manufacturing IC components. 1...Substrate, 2...Oxide film, 3...Oxide film on the scribe line.

Claims (1)

[Claims] 1. Forming a thick oxide film on a substrate, exposing and developing the oxide film using an IC photomask, and partially removing the oxide film by etching according to the development. , an IC component manufacturing method that produces an oxide film having a shape that matches a desired IC component, the thickness of the oxide film on the scribe line of the substrate is made equal to the thickness of a predetermined etching region of the oxide film, and the thickness of the oxide film on the scribe line of the substrate is equalized, A method of manufacturing an IC component, characterized in that etching of an etching area and etching of an oxide film on a scribe line are performed simultaneously, and the end point of etching is detected based on the oxide film on the scribe line.