JPH01290219A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a single-crystal Si film of a large area on an insulator substrate by a method wherein a temperature in the center of a part irradiated with a laser is made lower then that in a peripheral edge part, a single- crystallization process is started from the central part and a film whose thermal conductivity is higher than that of an insulator is filled directly under the central part of a laser beam. CONSTITUTION:A laser beam 9 whose intensity distribution is doubleridged is used; a temperature in the central part of a part irradiated with the laser beam 9 is made low. Accordingly, when a belt-shaped region directly above a polycrystalline Si stripe 7 of an Si film 87 is scanned in a direction as shown by an arrow 6, a temperature becomes lower than a part of only an insulator on both sides of the region of the Si film 8; a crystallization process is first started; the Si crystal stripe 7 of good quality can be formed; the same single- crystal stripe 7 can be formed without an interval. By this setup, an Si single- crystal film of a large area can be obtained on the insulator; an interlayer wiring part to an element formed in this Si single-crystal film can be formed through a gap of a belt-shaped buried layer of high thermal conductivity, a high-density wiring part can be formed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention involves depositing a polycrystalline or amorphous silicon film on an amorphous insulator substrate, and then melting the silicon layer by scanning a laser beam. , recrystallize to form a single-crystal silicon film and create a semiconductor device So! The present invention relates to a method of manufacturing a semiconductor device using technology.

[Conventional technology]

When forming a single-crystal silicon layer using Sol technology, a high-quality single-crystal layer cannot be obtained unless crystallization starts from the center of the silicon layer melted by laser beam scanning.
The figure shows an example of forming a single crystal silicon film using Sol technology on a silicon substrate on which semiconductor elements are integrated, and forming elements on the single crystal silicon film to construct a three-dimensional IC. After a polycrystalline silicon film 3 is laminated on the substrate 1 via an oxide film 2 to provide a flat surface, an oxide film 4 is further laminated, and the grooves formed in the oxide film are filled with polycrystalline silicon. Then, polycrystalline silicon stripes 5 are obtained. When the laser beam is scanned over this polycrystalline St stripe in the direction of arrow 6, much of the heat from the Si stripe is dissipated downward, where polycrystalline silicon M3 with high thermal conductivity exists, and the oxide film with low thermal conductivity is dissipated. Figure 3 shows the temperature distribution immediately after laser beam scanning, and the central part of the width of the Sl stripe 5 has a low temperature even in the morning.
The portion in contact with the oxide film 4 is the highest. As cooling progresses from this state, the center reaches the melting point T of St first and crystallization begins, and crystallization progresses toward the sides of the stripe where the melting point T is reached in sequence, yielding a high-quality Si single crystal stripe. .

[Llla to be solved by the invention] However, in order to obtain the above-mentioned temperature distribution, the SO technology's Sl single crystal film has to have a striped structure, and it is difficult to obtain a large area Sl single crystal film. Not possible, also Si
Since the polycrystalline Sl film 3 is interposed on one surface for heat diffusion downward from the stripe 5, when connecting the elements integrated on the St substrate 1 and the element formed on the Si single crystal stripe, the wiring is This problem of having to avoid the crystal St film 3 and not being able to form high-density glabellar wiring also exists when St@crystal stripes are stacked in multiple layers via interlayer insulating films.

&IB of the present invention solves the above problems and uses Sol technology to form a non-stripe, large-area single-crystal Si film on the Ifjl edge substrate without the need for a polycrystalline St film on the − plane. An object of the present invention is to provide a method for manufacturing a semiconductor device.

c! ! Means for Solving Ia] In order to solve the above problems, the present invention melts and recrystallizes a polycrystalline or amorphous silicon film deposited on an amorphous wA edge substrate by laser light irradiation. When manufacturing a semiconductor device using a single-crystalline silicon film made of silicon, a band-shaped layer with a predetermined width and thickness made of a material with higher thermal conductivity than the insulator of the substrate is placed in an insulator substrate. A polycrystalline or amorphous silicon film is deposited on the substrate in parallel with an interval of By scanning a laser beam having an equal width in the longitudinal direction of the band-shaped layer, the band-shaped layer is sequentially melted and recrystallized to form a 111 crystal film over the entire surface.

[Effect]

Because there is a band-shaped buried layer made of a material with higher thermal conductivity than an insulator directly under the center of the region of the polycrystalline or amorphous St film that is irradiated by one laser beam scan, 5111
The temperature is lower than that of the insulator-only parts on both sides of the W region, and crystallization begins first to form high-quality Si single crystal stripes. Similar single crystal stripes can be formed without any gaps between them, resulting in a large area. It is possible to obtain a Si single crystal film on an insulator. Moreover, since the glabellar wiring to the element formed in this Sl single crystal film can be performed through the gap between the band-shaped buried layers having high thermal conductivity, high-density wiring is possible.

〔Example〕

FIG. 1 shows a laser annealing process according to an embodiment of the present invention, and parts common to those in FIG. 2 are given the same reference numerals.

An oxide M2 is laminated on the 5liFi1, and a polycrystalline Si stripe 7 with a smooth thickness is embedded at intervals in the center of the oxide film 2. A polycrystalline Sl film 8 is grown on the entire surface.That is, the structure is such that the polycrystalline St film 3 and the polycrystalline Sl stripe 5 shown in FIG. The strip-shaped region is scanned in the direction of the arrow 6 with a laser beam 9 having a width of (W+D).The scanned Si film 8 has a polycrystalline SI stripe 7 with high thermal conductivity just below the center. A temperature distribution as shown by m41 in Fig. 4 is obtained.In other words, a temperature distribution similar to the temperature distribution of the polycrystalline St strip portion shown in Fig. 3 is obtained, and a high-quality Sl single crystal film is formed. Ru.

Next, the adjacent non-single-crystallized polycrystalline St film 8 is also scanned with the laser beam 9 to be made into a single crystal. By repeating this operation, the entire surface of polycrystalline si*a can be made into a single crystal.

FIG. 5 shows a laser annealing process according to another embodiment of the present invention, which differs from FIG. 1 in that a laser beam 9 having a bimodal intensity distribution is used. As a result, the temperature at the center of the irradiated area of the laser beam 9 is indicated by the dotted line 42 in FIG.
As shown in , it becomes even lower, and recrystallization from the edge of the laser irradiated area can be reliably suppressed. Wiring between the semiconductor element formed in the device layer 11 on the upper surface side of the silicon substrate l and the semiconductor element formed in the single-crystalline polycrystalline S1 film 8 is performed using the polycrystalline Si stripes of the oxide film 2. Since it can be performed through a gap of 7, high-density wiring between the eyebrows is possible.

Figure 6 t8) - (The diagrams sequentially show the steps before scanning with the laser beam of the embodiment of the present invention shown in Figures 1 and 5. First, approximately 4 μm of water is deposited on the silicon substrate 1. Oxidation of 111I2
(Fig. a) Even when elements are formed on the surface device layer of the silicon substrate 1, the unevenness is about 1-1, and the surface of the oxide film 21 is flattened to a thickness of 2 to 3-3. Next, the resist film 10 is left in a stripe pattern on the oxide film 21 by a lithography process (Figure b), and the oxide film 21 is etched to form a recess 23 (Figure c).
Then, the resist film 10 is removed (Fig. d), and a polycrystalline Si film 70 with a thickness of approximately 1 μm is deposited on the uneven oxide film 21 (Fig. e).
(Figure f), at this stage resist Wj410
the surface becomes flat. Thereafter, the surface of the polycrystalline Si film is oxidized by etching back the resist film IO and the polycrystalline Si film 70 using an etching gas or etching solution that has the same etching rate.
The polycrystalline St stripe 7 is formed on the same surface as the surface of the polycrystalline St stripe 7 (Figure g), and finally the oxide film 22 with a thickness of 0.5- or less
Then, a polycrystalline silicon film 8 having a thickness of 0.5- or less is deposited (FIG. h), and the oxide film 22 forms the oxide film 2 of FIGS. 1 and 5 together with the oxide film 21.

In the above embodiments, the single crystal silicon film was formed by melting and recrystallizing the polycrystalline silicon film by laser beam irradiation.
It can be similarly formed from an amorphous silicon film. Moreover, instead of the polycrystalline silicon stripe 7 for causing recrystallization to occur directly under the center of the irradiated laser beam, a stripe made of another material having higher thermal conductivity than the oxide film may be used.

〔Effect of the invention〕

According to the present invention, when a non-monocrystalline silicon film such as polycrystalline or amorphous silicon on an amorphous insulator substrate is made into a single-crystalline film by laser annealing, the center of the laser irradiation area is In order to obtain a high-quality single-crystal silicon film by starting single crystallization from the center at a lower temperature than By embedding a film made of a material such as polycrystalline silicon stripes, a non-single-crystalline film is striped on the surface layer of an insulating substrate in order to reduce heat dissipation to the side of the non-single-crystalline film during laser beam irradiation as in the conventional method. It is no longer necessary to fill in the form. As a result, it becomes possible to single-crystallize a non-single-crystal silicon film deposited over the entire surface of an insulating substrate, and also to enable high-density glabella wiring between elements formed in the single-crystal silicon film through the insulating substrate. Since this can be carried out using gaps such as polycrystalline silicon stripes in an insulator, it has become possible to manufacture highly functional semiconductor devices using Sol technology.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a laser annealing process for polycrystalline S1 according to an embodiment of the present invention, FIG. 2 is a perspective view showing a conventional laser annealing process for polycrystalline St, and FIG. Figure 4 is a temperature distribution diagram on the substrate surface during annealing. Figure 4 is a temperature distribution diagram on the substrate surface during laser annealing in an embodiment of the present invention. Figure 5 is a diagram showing the laser annealing process in a different embodiment of the present invention. Perspective views shown in Figs. 6(a) to 6(a) (eyes are shown in Figs.
FIG. 3 is a cross-sectional view sequentially illustrating steps before laser annealing in the embodiment of the present invention shown in the figures. 1: Silicon substrate, 2.21.22! Oxide film, 7: Polycrystalline Sl stripe, 8: Polycrystalline silicon film, Fig. 4, Fig. 5, Fig. 6

Claims (1)

[Claims] 1) When manufacturing a semiconductor device using a single crystal silicon film formed by melting and recrystallizing a polycrystalline or amorphous silicon film deposited on an amorphous insulator substrate by laser light irradiation, the insulator A band-shaped layer having a predetermined width and thickness made of a material having higher thermal conductivity than the insulator of the substrate is buried in parallel at a predetermined interval in the substrate, and polycrystalline or amorphous silicon is placed on the substrate. By depositing a film over one surface, and scanning each region of the silicon film divided just above the middle of the adjacent strip layer with a laser beam having a width equal to the width of the region in the longitudinal direction of the letter layer. A method for manufacturing a semiconductor device, characterized by sequentially melting and recrystallizing to form a single crystal film over the entire surface.