JPS6216509A - Manufacture of substrate for semiconductor device - Google Patents

Abstract

PURPOSE:To control the temperature distribution of a semiconductor film when it is recrystallized as well as to contrive improvement in crystallizability of the titled substrate by a method wherein the projections of a substrate holder having recesses and projections on the surface are brought into contact with a semiconductor film, and the whole is annealed. CONSTITUTION:The material, having a high coefficient of thermal conductivity, which is not deformed when a semiconductor film 3 is fused by beam annealing is suitable for a substrate holder 1. When a beam annealing is to be performed, as the tight adhesiveness of the substrate holder 1 and the semiconductor film 3 is an important factor for control of temperature distribution when the annealing process is performed, it is advisable that the above-mentioned materials are fixed using a vacuum chucking, and a beam 5 is made to irradiate from the back side of a transparent insulated substrate 2 when an annealing is performed. There are a laser beam, an electron beam and the like as the beam to be used for the above-mentioned annealing, and it is necessary that said beam is passed through the transparent insulated substrate 2. Generally, as hydrogen gas is contained in the a-Si film deposited by performing a plasma CVD method, the crystallizability after recrystallization by annealing can be improved by annealing for removal of said gas. It is generally known that hydrogen gas is removed by performing the annealing at the approximate temperature of 500 deg.C, and any annealing method which is performed at the temperature higher than said temperature can be used.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides a thin film transistor (TIFT) on an insulating substrate.
) T--Relates to a method of manufacturing a substrate for a semiconductor device, which allows a semiconductor film with better crystallinity to be obtained during manufacturing.

[Invention'ja! ! ] This invention uses a substrate holder with an uneven surface when beam annealing a semiconductor film on a transparent insulating substrate, and brings the semiconductor film into contact with the convex portion of the holder to reduce the amount of damage in the semiconductor film during annealing. This improves the temperature distribution and allows better crystals to be obtained.

[Conventional technology]

Conventionally, a semiconductor film deposited on an a-number substrate as shown in Fig.
As shown in Figure (6), the crystal grains were not sufficiently large because they crystallized from the low-temperature area around the beam.

[Problem that the invention seeks to solve]

In the conventional method, 9'! ! Even if the f-conductor was beam annealed, there was a problem in the temperature distribution of the semiconductor film during recrystallization, and the crystal grains did not become sufficiently large.

[Means for solving problems]

In order to solve the above-mentioned problem, the present invention brings the protrusions of the substrate holder, which has an uneven surface, into contact with the semiconductor film and performs beam annealing. Improves temperature distribution in a semiconductor film during crystallization.

[Effect]

i11! As shown in (#), when the protrusion of the substrate holder 1 and the semiconductor film 3 are brought into contact with the protective film 4 interposed between them, the temperature distribution of the semiconductor film 8 during recrystallization after beam annealing is as follows. As shown in FIG. 1 (6), crystallinity is improved because crystallization starts from the center of the beam.

〔Example〕

Examples of the present invention will be explained below with reference to the drawings. FIG. 1n) is a plan view of the first embodiment for explaining the annealing method of the present invention, and FIG. 1) is a sectional view taken along the line A' of FIG. 1b). The material of the substrate holder 1 may be any material as long as it has high thermal conductivity and does not deform when the semiconductor film 3 is melted by beam annealing. Examples include silicon, quartz,
/X Melting point metals such as chromium and molybdenum. The patterning of the convex portions can be made using photolithography technology. It is also possible to deposit the material desired for the convex portions on a flat holder and then pattern it using photolithography technology to provide concavities and convexities. That is, molybdenum is deposited on a silicon substrate to a thickness of 0.5 μm by sputtering or vapor deposition.
This is a method in which 10 pm of the film is deposited and then patterned. Next, a method for manufacturing a substrate to be beam annealed will be described. Examples of the transparent insulating substrate 2 include 1-quartz, alkali-free glass, and a glass surface coated with loquat to prevent impurities from diffusing from the glass. Materials for the semiconductor film 8 include polycrystalline silicon, amorphous silicon (a-Bi), germanium, and the like.

Deposition methods include sputtering, low pressure OVD, plasma O
'VD method etc. Here, α-a4-6 plasma O
A method of depositing by VD method will be explained. The deposition temperature was between room temperature and about 800°C. The raw material gas is mainly silane (#4H) or disilane (S4ml'l5).The film thickness is set between 0.05μ and IIts.Next, IJJi14 will be explained.This film is
It is provided so that when the semiconductor 8 is melted by beam annealing, it will not be deformed or damaged by direct contact with the holder 1. As an example of the material, silicon nitride (aj
Nz], silicon oxide (840 g), high melting point metals such as chromium and molybdenum. Deposition methods include evaporation, sputtering, and O"LD method, and the film thickness is 0.02μ.
It is set between 1 μ out of curiosity. Also, this protective film 4 is placed on the substrate holder 1 side.

Next, a beam annealing method for the semiconductor S will be explained.

During beam annealing, the substrate holder 1 and the semiconductor film 8
Since adhesion with the material is an important factor in controlling the temperature distribution during annealing, it is better to fix it by vacuum chucking.

In the finishing method, a beam 5 is irradiated from the back surface of the transparent insulating substrate 2, as shown in FIG. 1). Types of beams include laser beams, electron beams, and UV lamps, but they need to be able to pass through the transparent insulating substrate 2. Here, an argon laser beam is used to generate 1-B81'! The e-annealing method will be explained. Generally, 90-S4, which is deposited by plasma OVD, contains hydrogen gas in the film, so performing annealing to remove this gas improves the crystallinity after recrystallization annealing. What is the annealing method?

It is known that hydrogen gas can be removed at a temperature of about 500° C. or higher, and any annealing method that reaches this temperature or higher can be used. Further, this annealing may be performed before the semiconductor film 8 and the substrate holder 1 are closely layered. −
For example, in a vacuum or inert gas atmosphere, a-B
An example of annealing conditions in which the annealing is performed at an energy density that does not melt is power 12W and beam diameter 840μ.
Han.

The zero-order recrystallization annealing method performed at a scanning rate of 5 cN/age is performed using an argon laser in a vacuum or inert gas atmosphere, similar to the hydrogen gas removal annealing described above. Here, the beam width of the beam 6 is set to be at least larger than the width of the convex portion of the substrate holder 1, and the width of the beam 6 is set to be larger than the width of the convex portion of the substrate holder 1, and the width of the beam 6 is set to be larger than the width of the convex portion of the substrate holder 1.
) The beam is scanned along the convex portion of the substrate holder 1 in the beam scanning direction 6 shown in FIG. Examples of annealing conditions are: power 13W, beam diameter 180 μtrc, J scanning speed 50
There is cm/sac. As a result, the semiconductor t! during recrystallization. ! The temperature distribution of becomes larger and improves crystallinity. When a device such as a TPT is fabricated on a substrate as shown in FIG. 1 (6) after the above-mentioned annealing process, a device with high mobility and excellent electrical characteristics can be produced. There are other examples of the above-mentioned method of sealing using the substrate holder 1, so they will be explained.

FIG. 8 shows a second embodiment of the present invention, in which the convex portion of the substrate holder 1 is entirely triangular in shape.

This method is effective when the substrate holder 1 has a high thermal conductivity and the laser beam width is small. In addition, since the contact area with the semiconductor film 3 is small, the trouble that the substrate holder 1 and the semiconductor film 8 become closely layered and cannot be removed after annealing is reduced.

FIGS. 4b) to 4(c) show an eighth embodiment of the present invention.

This is a method in which the convex portions of the semiconductor film 8 and the substrate holder 1 are patterned in the same way, the convex portions of both 9 are layered closely (see FIG. 4 (Company)), and then beam annealing is performed. In addition, the fourth
) is a sectional view taken along line B-Bl of FIG. 4 (upper). Here, the area of the convex portion of the substrate holder 1 is made smaller than that of the island-shaped semiconductor film 31 in contact, so that the temperature distribution is as shown in FIG. to promote the development of As a result, the island-shaped semiconductor film 31 is crystallized as shown in FIG. 4(c).

FIG. 5 showing a fourth embodiment of the present invention shows a semiconductor film 8t-
Using a transparent substrate holder 11 when the deposited substrate is an opaque substrate 21 to the beam.

This is a method of annealing by irradiating the beam 6 from the holder side.

As an example, an argon laser is used as the beam 5, and an oxide film or the like is formed on the opaque substrate 21 on the silicon substrate.
Using a film deposited from 0.5μ to 8μ, a transparent substrate holder 11 made of glass such as quartz, and semiconductor 1! If α-゛a 4 of X8 is annealed, the temperature distribution at the time of recrystallization becomes as shown in FIG.

〔Effect of the invention〕

As explained in the several examples above, this invention uses a substrate holder with an uneven surface, brings the semiconductor film into contact with the convex portion of the holder, and anneals the semiconductor film during recrystallization. By controlling and improving the temperature P inside, there is an effect that crystallinity can be improved more than before.

[Brief explanation of the drawing]

Fig. 1) to (3) are diagrams showing the steps of the first embodiment of annealing of the present invention, Fig. 2) is a cross-sectional view for explaining the conventional annealing method, and Fig. 2) is FIG. 4 is a characteristic diagram for explaining the entire temperature distribution of the semiconductor film 8 during annealing. 8th
The figure is a sectional view showing a second embodiment for performing annealing according to the present invention. 4) to G)) are diagrams showing the steps of the eighth embodiment for performing annealing of the present invention, and FIG. 5 is a sectional view showing the fourth embodiment for performing annealing of the present invention. It is. 10. board holder, 2. . Transparent insulating substrate 30. Semiconductor film, 40. Protective film 50. Beam 61. Beam scanning direction and 0. Above the crystallized semiconductor film ↓ ↓ ↓ Figure 1 Conventional Heem Ryo Neil! Figure 2: Annealing and fitting 0 of the second embodiment! Toho↑Figure 3Figure 4

Claims (3)

[Claims] (1) When annealing a semiconductor film on the surface of a transparent insulating substrate with beam energy, a substrate holder with an uneven surface is used to bring the semiconductor film into contact with the convex portion of the holder, and energy is applied from the back side of the transparent substrate. irradiate,
A method for manufacturing a substrate for a semiconductor device, comprising annealing the semiconductor film. (2) The method for manufacturing a substrate for a semiconductor device according to claim 1, characterized in that a thin film having a higher melting point than the semiconductor film is inserted between the semiconductor film and the substrate holder. (3) The method of manufacturing a substrate for a semiconductor device according to claim 1 or 2, wherein the distance between the convex and convex portions of the unevenness of the substrate holder is smaller than the beam diameter.