JPS60216564A - Manufacture of semiconductor ic - Google Patents

Abstract

PURPOSE:To enable easy formation of a narrow groove for interelement isolation and the reduction in damage of the crystal by a method wherein a groove is formed in a semiconductor substrate by irradiation with light beams, and an isolation layer is formed by filling the groove with an insulator. CONSTITUTION:The groove 12 of required shape and depth is formed by repeatedly scanning the Si substrate 1 with laser beams. Next, an Si oxide film 15 is formed on the upper surface of the substrate 1 and the inner surface of the groove 12. Then, a polycrystalline Si layer 18 is deposited on the substrate 1. The surface is smoothened by removing the layer 18 of the region except inside the groove 12 through etching. In the manufacture as above, a narrow isolation layer can be formed by reducing damage in the crystal of the substrate 1 and without the need of mask patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a method for manufacturing a semiconductor integrated circuit having a separation layer formed by filling holes dug in a semiconductor substrate with an insulating material.

[Prior art and its problems]

Conventionally, in order to separate the elements of a semiconductor integrated circuit, a separation layer consisting of different turtleneck shapes is formed by diffusion from the surface.
They were separated using an N junction. However, it is difficult to narrow the width of the isolation layer due to diffusion because it also involves lateral diffusion, so as integrated circuit structures become smaller, a method of digging holes in the substrate and filling the holes with insulators has been used. became. Such narrow grooves are formed by plasma etching, in which highly reactive radicals are exposed to high-frequency iE.
Since it is generated at a source, its distribution is non-local,
K, which performs selective etching, required resist buttering. Furthermore, there was also the problem that the crystals were easily damaged.

[Purpose of the invention]

In contrast, it is an object of the present invention to provide a method for manufacturing a semiconductor integrated circuit in which narrow trenches for isolation can be easily formed and the influence on crystals is small.

[Key points of the invention]

According to the present invention, the above object can be achieved by processing a semiconductor substrate by irradiating a light beam to form a groove for isolation between elements, and filling the groove with an insulating material to form an isolation layer. Processing of a semiconductor substrate can be performed by accelerating ions generated by photoionization toward the substrate using an electric field or by using laser processing. It is also effective to generate an insulator buried in the trench by photochemical reaction.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, the silicon substrate 1 is placed at the bottom 3 of the reaction chamber 2.
is placed on the anode plate 4 of the reaction chamber 2, and the inside of the reaction chamber 2 is
After exhausting the air, chlorine gas was introduced from cylinder 6 with the flow rate controlled by a mass flow meter, and the pressure inside the reaction chamber was reduced to 0.
．． The temperature is adjusted to 2 Torr, and Ar laser light 8 having a wavelength of 5144 A is irradiated through a lens 9 so as to be focused directly above the substrate 1.

This light ionizes chlorine gas to produce chlorine ions. A power source 11 is provided between the cathode plate 10 surrounding the optical path and the anode plate 4.
By applying a DC bias, the chlorine ions are accelerated and collide with the silicon substrate 1, etching the substrate. Repeatedly scanning the beam of laser light 8
e of a predetermined shape and depth as shown in Figure 2 (,).
12 can be formed. In this case, silicon substrate 1
Heating with a heater (not shown) built into the bottom part 3 is effective in promoting the reaction with chlorine ions and reducing damage to the substrate crystal. Next, the atmosphere in the reaction chamber was changed to oxygen from the cylinder 13, and 80R light (synchrotron orbital beam radiation) 1 transmitted at a wavelength of 800 to 900 nm was added.
4, when the top of the replacement substrate 1 is scanned, oxygen ions are generated by high-density deep ultraviolet light, which are similarly accelerated by the DC bias applied between the anode plate 4 and the cathode plate IO, and are blown onto the top surface of the substrate 1 and A silicon oxide film 15 is formed on the inner surface of the groove 12, as shown in FIG. 2(b).

Furthermore, after exhausting the fR element in the reaction chamber 2, the cylinder 16 is
Introducing Kamo 5 IH4 gas and He gas from cylinder 17 and scanning the substrate l with laser beam 8.
A polycrystalline silicon layer 18 is deposited as shown in FIG. 2(b). The polycrystalline silicon layer 18 outside the groove 12 is then removed by etching to smooth the surface (see Figure C).
). Similar to the formation of the grooves 12, this etching can also be performed by layered ion etching using the original irradiation.

By forming a source region 19, a drain region, a polycrystalline silicon gate 22 doped with an impurity via a d-oxide film 21, and an aluminum interconnection layer 123 on the substrate on which the separation layer 18 has been formed in this manner. Insulation isolation 1
MO8) transistor resistors separated by m ts can be constructed within the integrated circuit &CM. The oxide film 15 serves to control the interface between the substrate and the insulating layer, and is made of impurity, oxide, polycrystalline 81 layer or Aa? The layer can be produced using a CVD method or a photochemical reaction. Further, the grooves may be formed by laser processing using an Ar laser in a CO2 atmosphere.

However, it is also possible to form only the grooves using light and to form the oxide film 15 by thermal oxidation or by forming the filling insulator by plasma CVDK. The surface can also be smoothed by etching with a liquid.

〔Effect of the invention〕

The present invention damages the crystals of the semiconductor substrate by performing etching by bombarding ions by photoionization or irradiation with light such as laser processing to form a dot for separating elements of a semiconductor integrated circuit. Therefore, a narrow separation layer can be formed without the need for mask patterning. Furthermore, since the filling of the insulating material in the groove can be performed in the same reaction chamber by irradiation with light, it is easy to maintain the cleanliness of the substrate, which has a great effect on the production of semiconductor integrated circuits with high concentration.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an apparatus for an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing an eleventh step of the process of an embodiment of the present invention. 1... Silicon substrate, 2... Reaction chamber, 4... lQ
N&: plate, 6.-chlorine cylinder, 8.=Ar laser beam, 10.. cathode plate, 12.. groove, 13-. oxygen cylinder, 14.-5 OR light, 15.. oxidation i, 16 ...
5i) I4 cylinder, 17...He cylinder, 1B...
・Polycrystalline silicon layer. artist! + Burial of Yamaguchi's death Figure 1

Claims (1)

[Claims] 1) In a method for manufacturing a semiconductor integrated circuit having a separation layer formed by filling a groove dug in a semiconductor substrate with an insulating material, the semiconductor substrate is processed by irradiation with an original beam to form the groove. A method for manufacturing a semiconductor integrated circuit, characterized by: 2. A method for manufacturing a semiconductor integrated circuit according to claim 1, wherein the semiconductor substrate is processed by accelerating ions generated by photoionization toward the substrate using an electric field. 3) % Permissible A method for manufacturing a semiconductor integrated circuit according to claim 1, characterized in that the semiconductor substrate is processed by laser processing. 4) A semiconductor integrated circuit characterized in that, in the method according to any one of claims 1 to 3, an insulator filled in the formed groove is produced by a photochemical reaction. Production method.