JPS61287234A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To simply selectively treat without position displacement by altering a laser light emitting intensity on the basis of information of the surface of the substrate obtained from the intensity variation of a reflected laser light due to the substrate. CONSTITUTION:A portion of an Si substrate emitted by a reaction laser light 1 is emitted by a laser light (e.g., HeNe laser) Z without relation to the reaction to detect by a detector 4 the reflected light 3. A stage 9 is moved to scan the entire surface. Since the intensity of the light 3 alters by the quality of the material of the surface, whether the treatment is required or not is judged by the output signal of the detector 4 to close or open a shutter 5. According to this method, when an aluminum layer 6 is emitted by a laser light 2 for detecting the surface state, since the aluminum has higher reflectivity than the SiO2 film, the shutter 5 is closed only when detecting the strong light 4 to selectively treat except aluminum wirings 6.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a semiconductor device using laser light as an energy source for a reaction.

Conventional technology Conventionally, as a manufacturing method for semiconductor devices using laser light as a reaction energy source, laser CVD, laser annealing, J-polymerization, annealing, etching, etc. are applied to the entire surface of a semiconductor substrate regardless of the surface condition of the substrate. This process performs the following processing. For example, when forming a silicon nitride film only on a certain part, multiple steps are required, such as first depositing the silicon nitride film on the entire surface, and then etching the film in areas other than the necessary parts using a hole/phosphorography process, etc. The film is left only in specific areas using

Problems to be Solved by the Invention As mentioned above, conventional techniques cannot selectively process only specific parts, and selective film formation, etching, etc. can be performed by combining multiple steps. However, deviation from the target location and complexity of the processing process pose problems.

In the present invention, when selectively processing using laser light, the position to be selected is detected using reflected light from the substrate,
It is simple and performs selective processing without positional deviation.

Means for Resolving Problems In order to solve the above-mentioned problems, the present invention has a mechanism for detecting the intensity of the reflected light from the semiconductor substrate of the laser light used in the reaction or the laser light provided for surface condition detection. .

It also has the function of changing the irradiation intensity of the laser beam used for the reaction on the semiconductor substrate based on the detected change in the reflected light intensity, thereby causing a selective reaction.

Since the reflectance of acting light differs depending on the material, by detecting the intensity of reflection of light on the surface of a semiconductor substrate, the material of the surface of the area irradiated with light can be determined. Depending on the material of the surface of the semiconductor substrate, the amount of reaction can be changed by changing the irradiation intensity of the laser light used for the reaction, making it possible to selectively cause a different amount of reaction only in a specific material part. .

Example The present invention will be described in detail below using the drawings.

(First Example) As shown in FIG. 1, reaction laser beam 1 (for example, Ar
F excimer laser) is Si layer 8.8102 layer 7,
A portion of the surface of the semiconductor substrate made of the aluminum layer 6, that is, a reaction region, is set to be irradiated with a laser beam 2 for surface state detection (for example, a HeNe laser). Reflection light 3 of laser light 2 for surface condition detection by semiconductor substrate
is detected by the analyzer 4. The semiconductor substrate is moved by a movable stage 9 perpendicularly or in the left-right direction with respect to the plane of the paper, and the entire surface of the semiconductor substrate is scanned with a laser beam. When scanning, the reflected light 30 depending on the material of the semiconductor substrate surface in the reaction area
The intensity changes, causing a change in the output signal of the analyzer 4. Using the output signal of the analyzer 4, it is determined whether the portion of the semiconductor substrate irradiated by the laser beam is an area that requires processing, and the shutter 6 is opened or closed.

The semiconductor substrate shown in Figure 1 is the first step in the multilayer wiring process.
This figure shows the state after layered aluminum wiring, and assumes that the surface is covered with aluminum wiring 6 and the SL02 layer. When scanning the entire surface with a laser beam, when the aluminum layer 6 is irradiated with the laser beam 2 for surface condition detection, a strong reflected light 3 is detected by the analyzer 4 because aluminum has a higher reflectance than 5IO2. be done. By closing the shutter 5 only when the reflected light 3 is strong, areas other than the aluminum wiring portion can be selectively processed. When this is applied to laser CVD, the detection laser 2 that constantly irradiates the semiconductor substrate
If you choose a laser beam that is not related to the reaction, such as HeNe, the film will not be deposited on the aluminum wiring while the shutter 6 is closed, and the film can be selectively deposited on areas other than the aluminum wiring, allowing the film to be deposited selectively on the semiconductor substrate surface. can be flattened. Figure 2 shows the state after flattening. No CVD film is formed on the aluminum 6, and a SiO2 film 10 is formed only on the SiO2 layer 7, resulting in a flat surface.

As described above, by using this method, flattening can be performed, and since positioning is performed by detecting the material of the surface, the selected portion does not shift.

Furthermore, selective annealing can also be performed by using, for example, a carbon dioxide gas laser as the reaction laser beam 1 and applying this method to laser annealing. In other words, it is possible to easily anneal only the portion excluding the aluminum having a low melting point without positional deviation.

(Second Embodiment 2) The example shown in FIG. 3 is an example in which the laser beam 1 for reaction (for example, a carbon dioxide laser) serves as the laser beam 2 for surface state detection. The reaction laser beam 10 and the reflected light 3 on the surface of the semiconductor substrate are detected by the analyzer 4 in the same manner as in Example 1. As a light intensity control mechanism for the reaction laser beam 1, a chopper 11 is used instead of the shutter 7 of Example 1, and the amount of reaction is changed by changing the rotational speed of the chopper 11. In areas where it is not necessary to cause a reaction, the time for which the laser beam 1 irradiates the semiconductor substrate surface is made longer than the time required to detect information on the substrate surface, and short enough to ignore the amount of reaction that occurs.

If the method of this embodiment is used, the structure will be simpler than that of the first embodiment, and the irradiation positions of the reaction laser and the detection laser will not be misaligned.

Effects of the Invention As described above, the present invention can selectively process only a specific portion of a semiconductor substrate, and moreover, since the condition of the substrate surface is actually detected, no positioning or scraping occurs.

This selective processing eliminates unnecessary damage and complexity.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a laser irradiation state in a method for manufacturing a semiconductor device according to a first embodiment of the present invention, and FIG.
FIG. 3 is a sectional view showing the state of the semiconductor substrate after planarization, which was planarized according to the embodiment, and FIG. 3 is a sectional view showing the state of laser irradiation in the method of the second embodiment. 1...Laser light for reaction, 2...Laser light for surface state detection, 3...Reflected light, 4...
...Analyzer, 5...Shutter, 6...
...Aluminum layer, 7...5lo2 layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] When manufacturing a semiconductor device using laser light as a reaction energy source, detecting the state of the surface of the semiconductor substrate in the laser light irradiation area by detecting changes in the intensity of the laser light reflected by the semiconductor substrate, A method for manufacturing a semiconductor device, characterized in that the laser beam irradiation intensity is changed based on the information.