JPS60160124A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide a groove having a highly accurate depth by a method wherein a groove is formed by etching on the impurity layer having the thickness same as the prescribed groove depth, and the etching is stopped at the point of time when the detection of discharged impurities becomes impossible. CONSTITUTION:An impurity layer is superposed on an Si substrate 1, a mask 2 is provided, and ion plasma 3 is made to irradiate. A groove 1a is etched, impurities are discharged from the impurity layer 10, and these impurities are detected 11. When the groove 1a reached the boundary of the layer 10 and the substrate 1, no impurities are discharged, and the irradiation of ion plasma 3 is stopped at this time. Then, the mask 2 is removed by etching and the titled semiconductor is completed. This method can also be applied to the material other than the Si substrate, other type of vapor-phase etching can be used too, a groove having accurate depth can be formed, the time when etching has reached the prescribed depth can be detected while the etching is being performed, and it has an excellent workability.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for manufacturing a semiconductor device in which a groove of a required depth is formed in a semiconductor substrate by vapor phase etching. The method of manufacturing the device was as shown in FIG. 1, which is a cross-sectional view of a semiconductor substrate portion shown in the order of steps. First, as shown in FIG. 1(a), a mask (2) is formed on the upper surface of a semiconductor substrate (1) made of silicon or the like. The semiconductor substrate (1) portion in this state is irradiated with ion plasma (3).

From this K, as shown in FIG. 1(b), the semiconductor substrate (1)
K pattern grooves (1a) are formed. Next, as shown in FIG. 1 (0), the mask (2) is removed with an etching solution or the like, and the pointed tip of the stylus (4) of a measuring instrument (not shown) is applied to the top surface of the semiconductor substrate (1). , move horizontally.

The depth of the groove (1a) is measured by the vertical movement K of the stylus (4). In the above conventional method, the depth of the groove (1a) is measured using the stylus (4). Since the width of the groove (la) is the width of the stylus (4)
It was not possible to measure if it was narrower than the diameter of .

Furthermore, it was not possible to measure the groove depth at the same time as etching, making it difficult to form groove depths with high precision.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the above-mentioned conventional methods, and involves forming an impurity layer under the surface of a semiconductor substrate to the same depth as the required groove depth, forming a mask on this semiconductor substrate, and forming a vapor phase Forming the etching groove by etching,
KL detects the released impurities and stops etching when they are no longer detected. Grooves of the required depth with high accuracy are formed, and the predetermined depth of the groove can be detected while etching, improving work efficiency. It is an object of the present invention to provide an improved method of manufacturing a semiconductor substrate.

[Embodiments of the invention]

Hereinafter, a method for manufacturing a semiconductor device according to an embodiment of the present invention will be explained with reference to cross-sectional views of a semiconductor substrate portion shown in the order of steps in FIG. First, as shown in FIG. 2(, ), an impurity layer Ql is formed in a semiconductor substrate (1) made of silicon or the like by a method such as ion implantation to a required groove depth. As the impurity, for example, iodine is used in the case of a p-type S1 substrate, and arsenic is used in the case of an n-type 81 substrate, and the amount of implantation is made small so as to have little effect on the characteristics. Next, Figure 2(b)
A mask (2) is formed on the upper surface of a semiconductor substrate (1) as shown in FIG. Ion plasma (
3) Irradiate.

As a result, one semiconductor substrate (1) is formed as shown in Fig. 2 (,).
As the etching progresses, the groove (la) becomes deeper.

At this time, until the groove depth has not reached the required depth, the impurity (10a) is released from the impurity layer (II) due to etching, and this is detected by the impurity detection device 0η as shown in Figure 2 (d). When the groove (1 &) reaches the required depth, it has reached the boundary where there is no impurity layer a1, and the impurity (l
oa) is not released and is not detected by the impurity detection device 1'il). Thereby, it can be determined that the groove (1a) has reached the required depth, and the irradiation of the ion plasma (3) is stopped. While etching with one-ion plasma (3) in this way, the groove depth is detected.Next, the mask (2) is removed with an etching solution and the second etching process is performed.
The state will be as shown in the figure (,).

In the above embodiment, plasma etching is used as vapor phase etching, but it can also be applied to other types of vapor phase etching such as reactive ion etching. However, the present invention can also be applied to other types of semiconductor substrates.

〔Effect of the invention〕

As described above, according to the method of the present invention, an impurity layer is formed below the surface of a semiconductor substrate to the same depth as the required groove depth, a mask is formed on this semiconductor substrate, and the etched groove is formed by vapor phase etching. Since impurities released during etching are detected and etching is stopped when they are no longer detected, the grooves can be formed to the required depth with high accuracy, and detection of reaching the predetermined groove depth while etching is possible. I can,
Workability is improved0

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a semiconductor substrate portion in the order of steps showing a conventional method for manufacturing a semiconductor device, and FIG. 2 is a sectional view of a semiconductor substrate in the order of steps showing a method for manufacturing a semiconductor device according to an embodiment of the present invention. Ol which is a cross-sectional view of the semiconductor substrate, la
...Groove, 2...Mask, 3...Ion plasma, 1
0... Impurity layer, 11... Impurity detection device Note that the same reference numerals in the figures indicate the same - or corresponding parts 0 Agent Masuo Oiwa No. 1 @

Claims (1)

[Claims] (1) Forming an impurity layer under the surface of the semiconductor substrate to the same depth as the required trench depth, and forming a mask on this semiconductor substrate,
A method of manufacturing a semiconductor device in which a groove is formed by vapor phase etching, impurities released by the formation of the groove are detected by an impurity detection device, and etching is stopped when the impurities are no longer detected.