JPS60198811A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To separate elements of high accuracy and high quality by annealing an epitaxial layer formed in an insulating film hole, then polishing the surfaces of the epitaxial layer and the insulating film, thereby stabilizing the characteristic of an element formed on the layer and preventing the wirings from disconnecting. CONSTITUTION:An epitaxial layer 3 is formed in the hole of an SiO2 film 2 on an Si substrate 1, the entirety is heated and annealed at 1,200-1,300 deg.C for approx. 10-20sec to recover the crystallinity. Then, the surface is lightly polished. Since the frictional resistance abruptly increases if a projection is erased, the finishing point of the polishing can be simply observed, and can be mirror- polished with good reproducibility. The surface after polishing is completely flat, no disconnection of wiring occurs to stabilize the characteristic of an element formed on the layer 3, an element separating structure of high accuracy and high quality can be obtained merely adding simple step to the conventional steps.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for planarizing and finely separating a semiconductor device.

[Prior art]

In general, various types of isolation structures between elements such as LSIs have been studied and put into practical use. In particular, oxide film isolation methods have been used for many years because they do not impair crystallinity and can reduce isolation capacitance and wiring board capacitance. It's here. Recently, in order to further increase the degree of integration, various separation methods have been studied to reduce bird's heads and bird's beaks. Among them, the selective epitaxial method has been developed in parallel with the development of technology for sharply cutting off oxide films, and is the method by which an isolated structure can be obtained with the simplest process.

Here, as an example of a conventional structure, the advantages and disadvantages of obtaining an isolated structure by selective epitaxial growth will be described.

FIG. 1 shows each step of a conventional selective epitaxial growth method. First, as shown in figure (a),
A portion of the Si oxide film 2 formed on the Si substrate 1 is opened by anisotropic ethoching, etc., and after pretreatment and removal of the naturally grown oxide film, Si H2Cj! is grown using an epitaxial growth apparatus. Epitaxial layer 3 is grown by decomposing 2 in H2. At this time, the same II (b
), it is possible to prevent anything from growing on the Si oxide film 2. This is because the decomposed Si migrates to a point where the energy is stable.
This is achieved by moving the Si oxide film 2
Since the nucleus is located on the Si substrate 1 rather than above, it grows there.

However, in reality, as shown in the same figure (C), Si
Si islands 4 (bird heads) also grow on the oxide film 2, and protrusions 5 (bird beaks) grow on the edges of continuous patterns.
may occur. It is thought that the Si island 4 grows here when there is dust, etc. that becomes the seed of a nucleus on the Si oxide film 2 that was not removed by pretreatment, and the protrusion 5 has a wide St that migrates. It is thought that this phenomenon is particularly likely to occur at pattern edges because it reaches the nearest Si from the top of the Sl oxide film 2 and grows without moving.

When such protrusions are present, there is a problem in that the protrusions are sharp and may cause wire breakage during wiring. Further, the crystallinity near the interface between the Si oxide film opening and the epitaxially grown Si is poor, and when a junction is formed, there is a problem of junction leakage. Especially in bipolar structures, the emitter
Collector shorts tend to occur in this area, and it is necessary to improve the crystallinity near the interface in order to stabilize device characteristics.

[Summary of the invention]

The present invention has been made in view of the above, and includes a method for manufacturing a semiconductor device in which an element isolation structure is obtained by an oxide film isolation method, in which an epitaxial layer formed in an opening in an insulating film is annealed. By restoring the crystallinity of the boundary between the epitaxial layer and the opening edge of the insulating film, and polishing the surfaces of the epitaxial layer and the insulating film flat, the epitaxial layer can be formed by simply adding a simple process. The purpose of the present invention is to provide a method for manufacturing a semiconductor device, which can stabilize the characteristics of the device that is connected to the semiconductor device, eliminate wiring breaks due to protrusions, and obtain a highly accurate and high quality device isolation structure. .

(Embodiments of the invention) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram for explaining a method of manufacturing a semiconductor device according to an embodiment of the present invention, and (8) to (tel) in the figure each indicate a cross-sectional structure of the semiconductor device at each step.

Next, the manufacturing method according to this embodiment will be explained using FIG. 2.

First, as shown in FIG. 31 layer 3 is grown in the opening by selective epitaxial growth. In this embodiment, the above S
In order to recover the crystallinity of the region near the interface between the opening of the i-oxide film 2 and the 31 layer 3, the region is subjected to laser beam annealing, lamp annealing, electron beam annealing, etc. as shown in FIG. It is recrystallized in For example, in lamp annealing, by heating the entire wafer at 1200 to 1300° C. for about 10 to 20 seconds, the crystallinity is restored to a level of practical use.

Next, as shown in fc) in the figure, the wafer surface is lightly polished using a polishing machine. During actual polishing, the frictional resistance of the polishing machine increases rapidly when the protrusion disappears, so the end point of polishing can be simply inserted into the WJ. Therefore, polishing can be performed extremely easily and with good reproducibility. The polishing machine is St.
Since it is used for mirror-finishing wafers, there is no need to worry about contamination of the next process.

According to the manufacturing method of this embodiment, as shown in FIG.
As shown in Figure fbl, after annealing, the pattern dependence and Si islands are reflected as they are, and the uneven structure is only slightly reduced, but after the annealing process, as shown in Figure fbl, it is completely flattened. . Therefore, as in the past, Barthead,
Wiring will not be disconnected due to bird beak etc.

Furthermore, since the epitaxial layer N3 is annealed and recrystallized, the characteristics of the element formed in the epitaxial layer 3 can be stabilized. Moreover, such a manufacturing method is simpler than any method that has been considered in the past.

Furthermore, according to this embodiment, as shown in FIG.
The remaining oxide film is used as an isolation film. According to this method, it is possible to isolate elements with extremely narrow spacing. This is because in the photolithography process, the width of the remaining pattern is narrower than that of the punched pattern. Therefore, with this method, a separation with a width of 0.5 to 1 μm can be easily obtained. Moreover, even though it is dry enching, the upper part is generally wider due to ion scattering, etc., so when separating bipolar, for example, there is a slight margin between the embedded fins 6, as shown in Figure 5. , which is advantageous in manufacturing.

In addition, in the above embodiment, when forming the epitaxial layer,
Although the selective epitaxial growth method is used to form the film, the same effect as in the above embodiment can be obtained even if the film is formed by a non-selective epitaxial growth method, that is, an entire surface epitaxial growth method. At this time, by performing the full surface epitaxial growth method, polycrystals grow on the oxide film, but by scraping the polycrystals down to the thickness of the oxide film or less, the same results as in the above embodiment can be obtained.

In addition, when an epitaxial layer is formed using the full-surface epitaxial growth method, as shown in Figure 4+al, a portion of the epitaxial layer can be left at 3゛ during polishing, and then the unnecessary portion can be removed by etching. , in the same figure), a structure in which the non-active region 3° is used as an electrode can also be easily obtained.

Furthermore, in the above embodiment, a Si substrate and a Si oxide film were used as an example of the substrate and the insulating film, but the same method can be used for epitaxial growth on semiconductor substrates such as GaAs and InSb, which are necessary for manufacturing semiconductor devices. Of course, it can be applied.

〔Effect of the invention〕

As described above, according to the method for manufacturing a semiconductor device according to the present invention, when obtaining an element isolation structure by the oxide film isolation method,
The epitaxial layer formed in the insulating film opening is annealed and recrystallized, and after the annealing process, the surfaces of the epitaxial layer and insulating film are polished flat, which adds a simple process to the conventional process. By simply doing this, it is possible to obtain a high-precision, high-quality element isolation structure.

[Brief explanation of the drawing]

Fig. 1 is a structural cross-sectional view for explaining a conventional device isolation method using a selective epitaxial layer; Fig. 2 is a structural cross-sectional view for explaining a method for manufacturing a semiconductor device according to an embodiment of the present invention; The figures are cross-sectional views of the structure before and after the polishing process in the embodiment of Fig. 2, Fig. 4 is a diagram showing another embodiment of the present invention, and Fig. 5 is a diagram for explaining the element isolation interval in the present invention. A1...Substrate, 2...Si oxide film (insulating film)
, 3...Epitaxial layer. In the drawings, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa Figure 1 (Q) Figure 2 (Q) Figure 3

Claims (3)

[Claims] (1) An insulating film is formed on the whole surface of a semiconductor substrate, an opening is provided in a part of the insulating film, an epitaxial layer is formed in the opening, and a boundary between the epitaxial layer and the edge of the opening is formed. 1. A method of manufacturing a semiconductor device, comprising: annealing at least a peripheral region including the epitaxial layer to restore crystallinity; and polishing the surfaces of the epitaxial layer and the insulating film to a flat surface. (2) The method for manufacturing a semiconductor device according to claim 1, wherein the epitaxial layer is formed by selective epitaxial growth. (3) The method of manufacturing a semiconductor device according to claim 1, wherein the epitaxial layer is formed by a non-selective epitaxial growth method.