JPH04299517A - Semiconductor device with silicon re-crystallized and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide the title silicon re-crystallized semiconductor device and manufacturing method thereof using a seed structure as well as forming an excellent single crystal silicon layer on an insulating film especially causing no uneven re-crystallization at all. CONSTITUTION:An insulating film 12 is formed on the surface of a single crystal silicon substrate 11 and then seed parts 131, 132 by the openings reaching the substrate 11 surface are evenly formed on the whole surface of the insulating film 12. Furthermore, sub-seed parts 151, 152 thinner than said insulating film 12 are formed respectively adjoining the seed part 131, 132 while a non-single crystal silicon layer 14 is formed on the insulating film 12 so that energy beams may scan on the whole surface of the layer 14 to make the recrystallization step advance from the seed parts 131, 132. At this time, the spaces of the sub-seed parts 151, 152 are set up corresponding to the accumulation effect produced by the beam scanning step so that the heat accumulated state on the whole surface may be equalized.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention relates to SOI (Silic
In particular, the present invention relates to a silicon recrystallized semiconductor device using a seed structure in which a single crystal layer is formed on an insulating film to form a three-dimensional IC, and a method for manufacturing the same.

0002

[Background Art] In SOI technology, in order to form a three-dimensional IC, an insulating film such as an oxide film is formed on the surface of a single-crystal silicon semiconductor substrate, and a layer of non-single-crystal silicon is further formed on this insulating film. However, various methods of melting this non-single-crystal silicon using an argon laser or an electron beam to form a single-crystal layer have been considered.

When a non-single-crystal layer on an insulating film is made into a single crystal in this way, as a means for determining the plane orientation, for example, the substrate surface is exposed on a part of the insulating film on a silicon substrate. An opening is formed, and the single crystal silicon semiconductor substrate and the non-single crystal layer on the insulating film are connected through the opening. Then, using the opening as a seed (seed crystal), epitaxial growth is performed from this opening.

[0004] Here, the energy beam of a laser or an electron beam scans the insulating film in a line, and the horizontal beam scan is sequentially moved in the vertical direction to perform continuous scanning many times. This beam scanning is performed across the seed portion to dissolve non-monocrystalline silicon including the seed portion. However, with this method, if a single crystal of 40 to 50 μm grows laterally from the seed portion, strain will accumulate in the crystal film.
Dislocations and grain boundaries begin to occur.

FIG. 9 shows a means for dealing with such a problem, in which a plurality of straight lines are formed on an insulating film 52 formed on the surface of a semiconductor substrate 51 so that the surface of the substrate 51 is exposed. Seed portions 531 , 532 , . . . are formed at equal intervals. The seed portions 531, 532, ... are formed to extend in a direction perpendicular to the scanning direction of the electron beam, and for example, n beam scans are performed on these seed portions 531, 532,...
31, 532, . . . are scanned across. A non-single crystal silicon layer 54 is formed on the insulating film 52 in which the seed portions 531, 532, . . . It is in contact with the substrate 51.

When the electron beam is scanned and irradiated in this manner, the heat distribution within the sample of the semiconductor substrate 51 and the insulating film 52 is such that heat accumulation occurs in the insulating film 52 and the seed part 531
, 532 , . . . conduction loss occurs to the substrate 51. Therefore, as shown in FIG. 10, heat is accumulated during beam scanning, resulting in non-uniform recrystallization. In this figure, the amount of heat storage in each region a to d increases sequentially.

As a means to solve these problems, a method disclosed in Japanese Patent Publication No. 2-36051 has been proposed. That is, in this method, the area of the seed portion is changed in accordance with the amount of heat storage, and the area of the seed portion is increased in a portion where the amount of heat storage is large, thereby increasing the amount of heat dissipated to the substrate portion. However, in such a method, the area of the seed portion increases, which inevitably reduces the effective area of the single crystal silicon layer on the insulating film.

[0008]

[Problems to be Solved by the Invention] The present invention has been made in view of the above points, and is intended to form a single crystal silicon layer so that the area on the insulating film can be effectively utilized. A high-quality single-crystal silicon layer is formed on the insulating film without causing non-uniform crystallization in this silicon layer, and silicon regeneration is performed so that the device formation region is set uniformly within the island set on the semiconductor substrate. The present invention aims to provide a crystallized semiconductor device and a method for manufacturing the same.

[0009]

[Means for Solving the Problems] In a silicon recrystallized semiconductor device according to the present invention, an insulating film is formed on the surface of a single crystal semiconductor substrate, and an amorphous silicon layer is formed on this insulating film. Openings are formed in the insulating film so as to be uniformly arranged on the surface of the semiconductor substrate, and a seed portion is formed where the amorphous silicon layer and the surface of the semiconductor substrate are brought into contact. In addition, quasi-seed parts are formed in which the thickness of the insulating film is set to be thin corresponding to these seed parts, and the amorphous silicon layer is recrystallized by scanning the energy beam from above the amorphous silicon layer. In this case, the area of the quasi-seed portion is set in accordance with the amount of accumulation accompanying beam scanning.

0010

[Function] In a semiconductor device configured in this manner, a heat dissipation effect by thermal conduction is set corresponding to the area of the quasi-seed part, and the amorphous silicon layer on the insulating film is uniformly heated, recrystallizing. The change is now uniform over the entire substrate surface,
An entirely uniform silicon recrystallized layer is formed. In this case, the element formation area is set including the quasi-seed part, excluding the seed part where the insulating film is opened, and the part where the element is formed is set uniformly within the island where it is set. .

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows its structure, in which an insulating film 12 made of a silicon oxide film is formed on the surface of a single-crystal silicon semiconductor substrate 11. A plurality of openings are formed in this insulating film 12 so as to extend in the vertical direction in the figure.
The seed portion 131 is formed so that the surface of the substrate 11 is exposed.
, 132, ... are formed. Then, an amorphous silicon layer 14 is formed on this insulating film 12, and this silicon layer 14 is brought into contact with the surface of the single crystal silicon semiconductor substrate 11 through the openings of the seed parts 131, 132, . ing.

The insulating film 12 also includes a seed portion 131 ,
Quasi-seed parts 151, 152,... are formed by thinning the insulating film 12 adjacent to the openings constituting the insulating film 12, and heat is efficiently transferred to the semiconductor substrate 11 in the quasi-seed parts 151, 152,.... Make it conductive.

Then, the amorphous silicon layer 14 is repeatedly scanned with an energy beam such as an argon laser or an electron beam in the horizontal direction in the figure, and the scanning position is sequentially moved in the vertical direction to cover the entire surface. perform beam scanning.

Next, the manufacturing method will be explained. First, as shown in FIG. 2, the surface of a single crystal silicon semiconductor substrate 11 whose crystal direction is set to (100) is
The entire surface is thermally oxidized at ~1200℃, and the thickness is 400~800A (
The insulating film 16 is formed to have a thickness of 1.5 angstroms. After that, a silicon nitride (Si 3N4) film 1 was formed in an LPCVD furnace.
Deposit 7. And seed parts 131, 132,
... and the quasi-seed parts 151, 152, ..., a photoresist pattern having openings corresponding to the portions is formed, the silicon nitride film 17 is etched, and then the silicon nitride film 17 is etched.
6-8 in wet HCl at 1000°C
Time oxidation is performed to form a LOCOS oxide film 18 as shown in FIG.

Once the LOCOS oxide film 18 has been formed in this manner, its surface is polished and planarized as shown in FIG. Next, as shown in Figure 5, C
An insulating film 19 is formed by depositing a VDSiO2 film or TEOS, and annealing is performed in nitrogen at 1000°C. Next, as shown in FIG.
, 132 , . . . , a resist pattern 20 having openings formed therein is formed, wet etching is performed by CVD etching, and taper etching is further performed as shown in FIG.

That is, the seed parts 131, 132,
... and the LOCOS oxide film 18 and the insulating film 1 with openings formed corresponding to the quasi-seed parts 151, 152, ...
9, an insulating film 12 is formed. Then, as shown in FIG. 1, an amorphous silicon layer 14 is formed on this insulating film 12, and by scanning an energy beam such as an electron beam, seed parts 131, 13 are formed.
2, the insulating film 1 is formed by epitaxial growth from...
2 so that a recrystallized silicon layer is formed on top of the second layer.

FIG. 8 shows an example of a semiconductor device constructed using a recrystallized silicon layer formed on the insulating film 12 in this manner. This recrystallized silicon layer is cut out, By implanting appropriate impurities, a source and a drain are formed by a PN junction, and a gate electrode 2 is formed.
By forming 11, 212, . . . , a MOS transistor is formed.

In the conventional SOI structure shown in FIG.
For example, if the electron beam is scanned from the upper left to the right, when the amorphous silicon layer is melted by the first beam irradiation, the silicon semiconductor substrate 51 and the insulating film 5
Due to the difference in thermal conductivity between the two seed parts 531 and 532
,..., heat tends to escape toward the semiconductor substrate 51,
Heat is accumulated on the insulating film 52.

When the beam scan advances to the second and third beam scans, the pitch width of this beam scan usually becomes 10 to 3.
Since it is as small as 0 μm, heat is accumulated in a downward direction in the scanning direction. The amount of heat accumulated is non-uniform over the entire surface as shown in FIG.

[0020] Due to such a heat storage effect, the temperature inside the island forming the recrystallized silicon layer increases; however,
Under optimal annealing conditions in the upper part of the island, peeling of the SOI layer occurs in the lower part of the island due to an increase in temperature within the island.

On the other hand, as shown in the example, SO
When the I layer is formed, heat is effectively dissipated from the single crystal silicon substrate 11 in the seed parts 131 , 132 , . . . as well as in the quasi-seed parts 151 , 152 , .
A uniform heat accumulation state is set within the SOI island, and the occurrence of peeling of the SOI layer during annealing or the like is reliably suppressed. Furthermore, portions corresponding to the quasi-seed portions 151, 152, . . . can be used as element forming regions.

[0022] In the embodiment, the seed portion 131,
132, . Furthermore, the insulating film 19 deposited in FIG.
In addition to the iO2 film, an insulating film made of Si 3N4, Six
It may also be composed of an Oy Nz insulating film.

[0023]

[Effects of the Invention] As described above, according to the present invention, when a recrystallized layer is formed by epitaxial growth of a seed portion by scanning an energy beam such as a laser beam or an electron beam, the total amount of heat storage can be made uniform. Since it is possible to perform high quality and uniform recrystallization. Further, the dead space in circuit design caused by the seed portion can be reduced, making it easier to design an IC circuit, and effectively improving the degree of integration.

[Brief explanation of drawings]

FIG. 1 illustrates a semiconductor device according to an embodiment of the present invention, in which (A) is a plan view of a seed structure;
) is an enlarged sectional view of a portion corresponding to line bb in FIG.

FIG. 2 is a cross-sectional configuration diagram illustrating the manufacturing process of the semiconductor device.

FIG. 3 is a cross-sectional configuration diagram illustrating the manufacturing process following FIG. 2;

4 is a cross-sectional configuration diagram further illustrating a manufacturing process following FIG. 3; FIG.

5 is a cross-sectional configuration diagram further illustrating a manufacturing process following FIG. 4. FIG.

6 is a cross-sectional configuration diagram further illustrating a manufacturing process following FIG. 5. FIG.

7 is a cross-sectional configuration diagram further illustrating a manufacturing process following FIG. 6. FIG.

FIG. 8 is a cross-sectional view showing an example of a semiconductor device manufactured by the above manufacturing process.

FIG. 9 is a diagram illustrating a conventional SOI manufacturing method.

FIG. 10 is a diagram illustrating the state of heat accumulation in the semiconductor substrate portion shown in FIG. 9;

[Explanation of symbols]

11... Single crystal silicon semiconductor substrate, 12... Insulating film, 13
1 , 132 , ... seed part, 14 ... crystalline silicon layer, 151 , 152 , ... quasi-seed part.

Claims (2)

[Claims] 1. An insulating film formed on a surface of a single-crystal semiconductor substrate, and a seed portion formed by an opening disposed in the insulating film in an even manner as a whole on the surface of the semiconductor substrate, A quasi-seed part is formed corresponding to the seed part and is formed by reducing the thickness of the insulating film, and an energy beam is scanned from above the seed part and the insulating film on which the quasi-seed part is formed. and a silicon recrystallization layer formed in the form of an insulating film, and the area of the quasi-seed portion increases as it goes toward the end of each scanning line of the electron beam and toward the rear of the scanning order. A silicon recrystallized semiconductor device made of silicon. 2. A seed portion formed in an insulating film formed on a surface of a silicon single crystal semiconductor substrate, which is formed by an opening exposing the surface of the semiconductor substrate, which is disposed in a generally averaged state on the surface of the semiconductor substrate; and a seed forming step of forming a quasi-seed part adjacent to the seed part to reduce the thickness of the insulating film, and forming a non-single crystal silicon layer on the insulating film including the seed part and the quasi-seed part. The surface of the insulating film on which the seed portion and the quasi-seed portion are formed is scanned by a scanning line in a first direction in a second direction.
a beam scanning step of scanning the energy beam so as to move sequentially in a direction of A method for manufacturing a silicon recrystallized semiconductor device, characterized in that the area thereof increases as the process progresses.