JPH04106950A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To enable a measurement of a film thickness without complicating structures and increasing number of processes, and to ensure the reliability of the quality of a product, by introducing the structure of leaving an insulating film at a part of a dicing line section. CONSTITUTION:After forming an insulation film on a substrate 1, a first insulation film 2a is formed on a device section 8. At this time, the first insulating film 2b is left on a partial region of a dicing line section 5 too. Then, after forming a metallic thin film on the film 2a, a first wiring film 3 is formed on the film 2a. Further, the film 3 is covered with an insulating film, and this film comes into a second insulating film 4. When in the section 5, the film thickness of the film 4 is measured using a measuring instrument of an optical system, a beam 7a is projected on the film 2b in the section 5, from the measuring instrument of the optical system. Then, the reflection bean 7b thereof is observed, and the film thickness is measured. Thereby, the substrate in the section 5 is prevented from roughening, and the impossibility of measuring film thickness is made avoidable. Further, it is made possible to manage the film thickness with a high accuracy and reliability, and without complicating structures and increasing number of Processes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device and a method of manufacturing the same, and particularly relates to a structure of a dicing line portion and a method of manufacturing the same.

[Conventional technology]

FIG. 3 is a cross-sectional view of a dicing line portion of a conventional semiconductor device.

In the figure, 1 is a semiconductor substrate (hereinafter simply referred to as a substrate) made of, for example, single crystal Si, 2a is a first insulating film formed on the substrate 1, and 3 is a semiconductor substrate formed on the first insulating film 2a. 4 is a second insulating film formed to cover the first wiring film, 5 is a dicing line portion formed by removing the insulating film for dicing, and 6 is a dicing film. Roughness of the Si substrate in the line part 5, 7a is the incident light of the optical film thickness measuring device used for film thickness measurement (hereinafter referred to as incident light), 7b is the reflection of the incident light 7a of the optical film thickness measuring device Light (hereinafter referred to as reflected light), 8 is an element part forming an element. As shown in the figure, in the dicing line portion 5, the first insulating film 2a is completely removed.

Hereinafter, the manufacturing process of a semiconductor device having such a structure will be explained with reference to FIG.

First, the first insulating film 2a is formed by forming an insulating film on the substrate 1 by a thermal oxidation method or a CVD method, and then patterning it through a photolithography process. At this time, the insulating film is completely removed at the dicing line portion 5, and the Si substrate 1 is exposed (FIG. 4(a)).

Next, the first wiring film 3 is formed by forming a metal thin film on the first insulating film 2a by sputtering or the like, and then patterning it through a photolithography process. In this case, the substrate 1 exposed at the dicing line portion 5 is also etched by the CF4 gas used during patterning, so that the surface becomes rough 6 (FIG. 4(b)).

Furthermore, for example, CV
An insulating film is formed by the D method or the like. This becomes the second insulating film 4 (FIG. 4(C)).

In order to control the film thickness of the second insulating film 4, the film thickness is measured at the dicing line section 5 using the incident light 7a and the reflected light 7b of an optical film thickness measuring device.

[Problem to be solved by the invention]

In this manner, in the conventional semiconductor device, the insulating film on the Dyson line portion 5 is completely removed. This is because, during dicing, if there is an insulating film on the entire surface of the same part, the dicing counter will be severely worn out, and also to prevent cracks in the insulating film that occur in the same part from reaching the element part 8.

Therefore, the S1 surface is exposed in the dicing line portion 5, and this S1 is etched by CF and other gases used when processing wiring using, for example, aluminum alloy. At this time, the carbon, oxide film, etc. that cover the S1 surface in minute regions act as a micromask, causing unevenness, resulting in deterioration of the surface morphology, so-called substrate roughness.

Therefore, after this, when measuring the thickness of the second insulating film at the dicing line section 5 to control the thickness of the second insulating film, the reflected light 7bj reflected by the substrate with respect to the incident light 7a of the measurement light will be affected by the roughness of the substrate. The particles are scattered, making measurements impossible or impossible to measure accurately, which poses a major problem in process control.

Furthermore, in the submicron era, film forming equipment is replacing the previous batch type with plate type. Therefore, film thickness control using a monitor wafer, which was possible with the hatch method, is no longer possible, so film thickness control using a patterned actual wafer is essential, and if this film thickness monitoring becomes impossible, product reliability This is a serious problem.

The present invention was made in order to solve these problems. The purpose is to provide a device and a method for manufacturing the same.

Means for Solving 5 Problems] A semiconductor device according to the present invention prevents roughness of a Si substrate,
This structure leaves an insulating film in a part of the dicing line so that film thickness can be measured.

In the method for manufacturing a semiconductor device according to the present invention, a first insulating film is formed in an element formation region on a semiconductor substrate, the first insulating film is also left in a part of a dicing line portion, and then the entire surface is a metal thin film is provided on the first insulating film and etched so as to leave it only on the first insulating film in the element forming region;
Further, a second insulating film is formed on the entire surface, and the thickness of the second insulating film is measured on the first insulating film in the dicing line portion.

[Effect]

In the semiconductor device of the present invention, since the structure is such that an insulating film is left in a part of the dicing line part, it is possible to prevent roughness of the Si substrate in the dicing line part due to CF4-based etching gas. Since diffuse reflection of light is prevented, film thickness measurement becomes possible.

In addition, in the method for manufacturing a semiconductor device of the present invention, when forming the first insulating film on top of the element formation, two regions of the dicing line portion are removed in the first w! ,
Since two parts of the edge film were left behind, during the metal thin film etching process in the subsequent process, some areas of the dicing lines where the first insulating film was left were roughened. Not alive. Therefore, precise film thickness measurement can be achieved at the dicing line portion without complicating the structure or increasing the number of steps.

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

Note that the description of parts that overlap with the description of the conventional technology will be omitted as appropriate.

FIG. 1 is a sectional view showing the structure of the main part of a semiconductor device according to an embodiment of the present invention. In Figure S, 1.2a,
3 to 8 are the same as the conventional one; 2b; the first insulating film formed on the dicing line portion 5;

Hereinafter, a method for manufacturing a semiconductor device having such a structure will be explained with reference to FIG.

FIGS. 2(a) to 2(C) are cross-sectional views of each main process showing the manufacturing process of a semiconductor device according to an embodiment of the present invention.

First, an insulating film is formed on the substrate 1 by a thermal oxidation method or a CVD method. Thereafter, a first insulating film 2a is formed on the element portion 8 by patterning through a photolithography process. At this time, the first insulating film 2b is also left in a part of the dicing line portion 5 (FIG. 2(a)).

Next, a metal thin film is formed on the first insulating film 2a by a sputtering method or the like, and then patterned with a gas such as CF or other gases, thereby forming a first wiring film on the first insulating film 2a. 3 (Fig. 2 et al.)).

Furthermore, for example, CV
An insulating film is formed by the D method or the like. That is the second insulating film 4
(Figure 2 (C)).

Through the above steps, the semiconductor device shown in FIG. 1 is completed.

Thereafter, when measuring the film thickness of the second insulating film 4 using an optical measuring device at the dicing line section 5, as shown in FIG. membrane 2
Light 7a from an optical film thickness measuring device is incident on the film 7b, and the reflected light 7b is observed to measure the film thickness.

In this embodiment, as described above, a part of the dicing line portion 5 is covered with the first insulating film 2b, so that the basic manufacturing process (FIG. 2(b)) The Si surface covered with the first insulating film 2b can be protected from the CF4-based gas used, which has the effect of preventing substrate roughness. As a result, in the above-mentioned film thickness measurement, the reflected light 7b is specularly reflected with respect to the incident light 7a from the film thickness measuring device, and the conventional problem of inability to measure due to diffuse reflection is avoided. Therefore, the film thickness of an actual wafer with a pattern can be controlled with high precision, and reliability can be improved.

Note that since the first insulating film 2b is left only in a part of the dicing line section 5, even if a crack occurs in the insulating film 2b during dicing in the first insulating film 2b section, The cracks do not affect the element section 8.

Further, since this insulating film 2b is formed at the same time as the first insulating film 2a of the element section, there is no need to increase the number of manufacturing steps, and the present structure can be easily obtained with the same number of steps as in the prior art.

In the above embodiments, the case where the wiring layer is one layer is shown, but
Even in a multilayer wiring constructed by successively forming multiple layers of wiring films with insulating films interposed therebetween, if the insulating film is left on the dicing line portion 5 in the process shown in FIG. 2(a), the same effect can be obtained in the subsequent process. It will be done.

Note that the first insulating film 2 formed on the dicing line portion 5
It is preferable that b be thicker in consideration of over-etching.

〔Effect of the invention〕

As described above, according to the semiconductor device according to the present invention, since the insulating film is left in a part of the dicing line part,
It acts as a mask during etching with CF4 gas and prevents substrate roughness at the dicing line, and also avoids the inconvenience of being unable to measure with an optical film thickness measurement device due to this, improving product quality reliability. There is an effect that can be improved.

Furthermore, according to the method for manufacturing a semiconductor device according to the present invention, when forming the first insulating film in the element formation region, the first insulating film is simultaneously left in a part of the dicing line portion. This has the effect of providing a structure in which film thickness can be controlled with high precision and high reliability at the dicing line portion without complicating the structure or increasing the number of steps.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of a dicing line portion of a semiconductor device according to an embodiment of the present invention, and FIGS. 2(a) to (C) are cross-sectional views showing the manufacturing process of the semiconductor device shown in FIG. Third
The figure is a cross-sectional view of the dicing line part of a conventional semiconductor device.
FIGS. 4A to 4C are cross-sectional views showing the manufacturing process of a conventional semiconductor device. In the figure, 1 is a substrate, 2a is a first insulating film, 2b is a first insulating film formed in the dicing line portion 5, 3 is a first wiring film, 4 is a second insulating film, and 5 is a dicing film. Line part, 6 is substrate roughness, 7a is incident light of optical film thickness measuring device,
Reference numeral 7b indicates reflected light from an optical film thickness measuring device, and 8 indicates an element section. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) In a semiconductor device having a dicing line section on a semiconductor substrate, an insulating film is formed on a part of the substrate in the dicing line section, and the insulating film protects the substrate from etching gas in a later process. 1. A semiconductor device, characterized in that the surface is kept flat and the thickness of the insulating film can be measured by irradiating the insulating film with light. (2) forming a first insulating film in the element formation region on the semiconductor substrate and simultaneously forming the first insulating film in a part of the dicing line portion; and after forming a metal thin film on the entire surface; a step of leaving it only on the first insulating film in the element formation region by etching; a step of forming a second insulating film on the entire surface; and a step of etching the first insulating film on the dicing line portion using an optical device. A method for manufacturing a semiconductor device, comprising the step of measuring the thickness of the second insulating film.