JPS603772B2 - Manufacturing method for semiconductor devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a semiconductor region is formed by diffusing an impurity having a desired conductivity type from the main surface side of the semiconductor substrate, and is insulated from the main surface of the semiconductor substrate. The present invention relates to a method for manufacturing a semiconductor device having a structure in which a conductive layer is formed to connect and extend a semiconductor region formed in a semiconductor substrate, and in particular, the semiconductor region can be obtained with high precision in a small number of steps, and The purpose of this invention is to propose a novel method for manufacturing such a semiconductor device, which can easily provide a structure in which a conductive layer extends on the main surface of a semiconductor substrate while being insulated therefrom.

The present inventors have discovered that an inorganic photoresist material layer consisting of a first layer containing selenium as a main component (amorphous chalcogenide layer) and a second layer containing silver or silver has high resolution as a photoresist. Even if an inorganic photoresist material layer having such high-resolution characteristics contains a relatively large amount of impurities that impart a desired conductivity type, the high-resolution characteristics as a photoresist will not be impaired. Therefore, the inorganic photoresist material layer containing the impurity is patterned on the semiconductor substrate, and the patterned inorganic photoresist material layer containing the impurity is used as the impurity-containing layer. If the impurities are thermally diffused from the layer into the semiconductor substrate, there is no need to form a separate impurity diffusion layer on the semiconductor substrate and then thermally diffuse the impurities into the semiconductor substrate. A semiconductor region having a conductivity type can be formed with high precision;
If this thermal diffusion of impurities is performed while the impurity-containing layer is covered with a heat-resistant insulating coating layer, the inorganic photoresist material layer constituting the impurity-containing layer may be unnecessarily sublimated or evaporated. The reason is that impurities can be effectively thermally diffused into the semiconductor substrate, and a heat-resistant insulating coating layer that brings about this effect can be coated with a conductive layer connected to the semiconductor region formed within the semiconductor substrate. It was discovered or confirmed that the magnetic layer can be extended and formed into a layer while insulating it from the semiconductor substrate.

The present invention was proposed based on such discovery or confirmation. An example of the present invention will be described below with reference to the drawings. For example, an N-type semiconductor substrate 1 as shown in FIG. 1 is prepared in advance, and a P-type semiconductor substrate 1 as shown in FIG. Layer 3 whose main component is selenium containing impurities and its layer 3
An inorganic photoresist material layer 5 consisting of silver or a layer 4 containing silver formed thereon is formed.

In fact, such an inorganic photoresist material layer 5 is formed on the main surface of the substrate 1 by vacuum evaporation or sputtering to form a layer 3 containing selenium as a main component, preferably selenium and germanium as main components. A layer 4 is formed on the layer 3 by vacuum evaporation or sputtering, or by immersing the layer 3 in a solution containing silver ions. It can be obtained by forming a chalcogenide layer, a silver halide layer, or the like.

Next, as shown in FIG. 3, the inorganic photoresist material layer 5 is exposed to light, electron beam, ion beam, etc. in a desired pattern from the layer 4 side as shown by the reference numeral 6, and the layers 3 and 4 are exposed. The exposed area is obtained as a region 7 having a higher resistance to a developer made of an alkaline solution than the unexposed region 3a of the layer 3, and then developed using a developer made of an alkaline solution. As shown in FIG. 4, the unexposed regions 3a and 4b of layers 3 and 4 are removed from the substrate 1, leaving the region 7, and thus the region 7 is covered with a photoresist material having a pattern corresponding to the exposure pattern. The layer 5 is obtained as an impurity-containing layer containing P-type impurities.

Next, as shown in FIG. 5, a heat-resistant insulating coating layer 8 made of an insulating material such as Si02 or Si3N4 is formed on the substrate 1, covering the region 7 and therefore the impurity-containing layer, by various methods known per se.

Next, heat treatment is performed to form a P-type semiconductor region 9 in the region below the impurity-containing layer 7 of the substrate 1 by thermally diffusing the P-type impurity from the impurity-containing layer 7, as shown in FIG.

In this case, due to the heat treatment, depending on the material of the insulating coating layer 8, the material constituting the impurity-containing layer 7 may completely or partially dissolve into the insulating coating layer 8, and the impurity-containing layer 7 may disappear completely or only a small amount remains as shown in the figure. This is the result.
Next, a window 10 for exposing the semiconductor region 9 to the outside is formed at a position corresponding to the semiconductor region 9 of the heat-resistant insulating coating layer 8 using a method known per se, and the impurity-containing layer 7 is If it remains on the semiconductor region 9 as shown in FIG. 8, it is removed from the semiconductor region 9 by heat treatment, etching treatment, etc. as shown in FIG. A ninth layer is formed on the insulating coating layer 8.
As shown in the figure, a conductive layer 11, for example, a wiring layer, which can be connected and extended to the semiconductor region through a window 10, is formed by means known per se, and is thus formed in an N-type semiconductor substrate 1 on its crown surface 2. A semiconductor region 9 in which P-type impurities are diffused is formed, and a conductive layer 11 is formed on the main surface 2 of the semiconductor substrate 1, insulated from this by an insulating coating layer 8, and connected and extended to the semiconductor region 9. A semiconductor device having a configuration in which is formed is obtained.

An example of the present invention has been clarified above, and according to the present invention, on the main surface 2 of the semiconductor substrate 1, a layer 3 mainly composed of selenium containing an impurity imparting a desired conductivity type, An inorganic photoresist material layer 5 consisting of silver or silver-containing layer 4 formed on 3 is formed, and then the inorganic photoresist material layer 5 is exposed to light in a desired pattern, followed by development treatment to form an inorganic photoresist material. An impurity-containing layer 7 having a pattern corresponding to the exposure pattern of the layer 5 is formed, and then a heat-resistant insulating coating layer 8 is formed on the main surface 2 of the semiconductor substrate 1 to cover the impurity-containing layer 7. As a result, a semiconductor region 9 is formed in which impurities from the impurity-containing layer 7 are diffused into a region under the impurity-containing layer 7 of the semiconductor substrate 1.
Therefore, the semiconductor region 9 can be obtained with a simple and small number of steps, and the semiconductor region 9 can be formed by exposing the inorganic photoresist material layer 6 formed on the substrate 1 to light, followed by a development treatment. Since the impurity-containing layer 7 obtained by the above method can be used as an impurity source for obtaining the semiconductor region 9, it is possible to obtain a pattern with high precision according to the exposure pattern for the inorganic photoresist material layer 5. Furthermore, when forming the semiconductor region 9 in the semiconductor substrate 1 using the impurity-containing layer 7 as an impurity source, since the insulating coating layer 8 is provided, the impurity-containing layer 7 can be prevented from being sublimated or evaporated unnecessarily. The impurities contained in 7 are effectively diffused to the substrate 1 side without being unnecessarily diffused to the outside, and therefore it is possible to easily obtain the semiconductor region 9 having the desired impurity concentration. Further, since the inorganic photoresist material layer 5 is composed of the layer 3 containing selenium as a main component and the layer 4 containing silver or silver formed thereon, an impurity-containing layer 7 is obtained with high sensitivity and high precision. I can do it,
Therefore, it has great features such as being able to obtain the semiconductor region 9 with high precision.

Further, after obtaining the semiconductor region 9 with the above-mentioned characteristics, a step is taken to form a window 10 in the heat-resistant insulating coating layer 8 and then forming a conductive layer extending over the insulating coating layer 8. A semiconductor region 9 is formed on the main surface 2 of the semiconductor substrate 1 and is insulated therefrom.
Since it is possible to form a conductive layer 11 that can be connected and extended to the conductive layer 11, the conductive layer 11 can be easily obtained.
Moreover, the structure in which the conductive layer 11 extends over the main surface 2 of the semiconductor substrate 1 in an insulated manner causes impurities contained in the impurity-containing layer 7 to unnecessarily diffuse to the outside when the semiconductor region 9 is formed by heat treatment. Insulating coating layer 8 which is also applied for
Since it is obtained by applying the above, it has great features such as being able to easily obtain the configuration.

The above description merely shows an example of the present invention, and the above-mentioned "N type" can also be read as "P type", and the semiconductor region may be formed to have the same conductivity type as the semiconductor substrate. It is also possible to use plasma etching as the development treatment for the inorganic photoresist material layer, and various other modifications may be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIGS. 1 to 9 are schematic cross-sectional views in successive steps showing an example of a method for manufacturing a semiconductor device according to the present invention. In the figure, 1 is a semiconductor substrate, 2 is a main surface, 3 is a layer mainly composed of selenium, 4 is a layer containing silver or silver, 5 is an inorganic photoresist material layer, 7 is a region, and 8 is a heat-resistant insulating coating layer. , 9 is a semiconductor region, 10 is a window, and 11 is a conductive layer. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] 1. On the main surface of the semiconductor substrate, a first layer mainly composed of selenium containing impurities that imparts a desired conductivity type, and a second layer containing silver or silver formed on the first layer. A process of forming an inorganic photoresist material layer, exposing the inorganic photoresist material layer in a desired pattern, and a subsequent development treatment, thereby removing impurities from the inorganic photoresist material layer having a pattern corresponding to the exposure pattern. forming a heat-resistant insulating coating layer on the main surface of the semiconductor substrate, covering the impurity-containing layer; and covering the impurity-containing layer with the heat-resistant insulating coating layer. forming a semiconductor region in which impurities from the impurity-containing layer are diffused in a region of the semiconductor substrate under the impurity-containing layer by heat treatment in a state where
forming a window in the heat-resistant insulating coating layer that allows the semiconductor region to be exposed to the outside; forming a conductive layer on the heat-resistant insulating coating layer that connects and extends to the semiconductor region through the window; A method for manufacturing a semiconductor device characterized by comprising: