JPS5811095B2 - How to use hand-made products. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a semiconductor substrate with a thickness of several tens of micrometers.
The present invention proposes a method for forming through-holes with a high sugar precision.

Conventionally, as a method of forming through holes in a semiconductor substrate,
This is done mechanically using drills, ultrasonic processing, lasers, etc.

However, it has been difficult to form through holes as small as several micrometers with good edge precision using mechanical methods.

In view of the above, it is an object of the present invention to provide a through-hole forming method that does not involve mechanical methods and can obtain through-holes with good edge precision.

The method according to the present invention includes a step of forming an oxide film on both sides of a semiconductor substrate, a step of forming a window surrounding an area corresponding to a through hole of a predetermined size in the oxide film on the surface of the semiconductor substrate, and a step of forming an oxide film on both sides of a semiconductor substrate. a process of diffusing impurities into the semiconductor substrate that is less corroded by etching than the semiconductor substrate; a process of forming a window at a position corresponding to a window formed on the back surface of the semiconductor substrate; This method is characterized in that it includes a step of etching with a dependent etching solution and a step of removing an oxide film formed on both surfaces of the semiconductor substrate.

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

FIGS. 1 to 5 sequentially illustrate the steps constituting the method of the present invention.

FIG. 1 shows the process of forming oxide films on both sides of a semiconductor substrate Si and providing a window in a part of the oxide film.

The semiconductor substrate Si has approximately 100 planes in the board surface direction (this 100
The faces are 100 faces, 010 faces, 001 faces, 100 faces...
...is a general term.

), for example, a silicon wafer cut out.

Both surfaces are oxidized to form an oxide layer, in this case a SiO2 layer.

Next, a window B is formed in the oxide layer formed on the surface by etching, surrounding a region A (the opening in FIG. 1 is a view from the top) corresponding to the size of a predetermined through hole.

Next, as shown in FIG. 2, an impurity μP is implanted into the semiconductor substrate Si to a depth of several μm by diffusion through a window B formed on the surface.

At this time, an oxide layer S on the surface oxide layer SiO2 and window B
iO2 is formed.

Here, the impurity uP needs to be less corrosive by etching than the semiconductor substrate, as will become clear from the process described later.

For example, boron B (
Bo-ron) is used on the semiconductor substrate several μm from the window B.
Diffusion implantation is required to a depth of .

Figure 3 shows an oxide layer B formed on the back surface of a semiconductor substrate Si.
It is shown that a window W is formed in iO2 at a position corresponding to window B.

Next, in the process shown in FIG.
, P, W (solution consisting of ethylenediamine 17C,C, pyrocatechol 3gr, water 8C,C) or Na
By etching through the window W with a basic solution such as CH or KOH, a cone-shaped recess H is formed from the back surface.

For example, A, P, and W are the 100 axes of single crystal silicon (the 100 axes are the 100 axis, 012 axis, 00 axis).
1 axis, 100 axis...) direction has the greatest erosiveness, followed by 110 axis (
These 110 axes are 110 axis, 101 axis, 011 axis, 1
The 10 axes... shall be collectively referred to as the 10 axes.

), 111 axis (this 111 axis, 111 axis, 111 axis,
... shall be collectively referred to as...

) is known to have crystallographic properties in which corrosiveness decreases in the order of

Therefore, by cutting out a piece of silicon with 100 planes and etching it from this plane through the window W with an etching solution that is dependent on the crystal direction, such as A, P, W, etc., it is difficult to be attacked by this etching solution111. By exposing the surface, a cone-shaped recess H as shown in FIG. 4 is formed.

As mentioned above, the portion uP is left as shown in FIG. 4 because it is less susceptible to corrosion than the semiconductor substrate due to impurity diffusion.

Next, an oxide layer S formed on both sides of the semiconductor substrate Si
By removing iO2 by etching etc., the fifth
As shown in the figure, through holes are formed in the semiconductor substrate Si.

Through the above process, a through hole with high edge precision can be formed without using mechanical methods.

In other words, the edge accuracy can be improved by photoetching the area A corresponding to the size of the through hole when forming the window B on the surface oxide layer SiO2, and it is much better than forming the through hole by machine. Needless to say, this is done with great precision.

Although silicon Si was used as an example of the semiconductor substrate in the above description, the present invention is not limited to silicon semiconductor substrates by appropriately selecting the composition of the etching solution.

Furthermore, the present invention makes it possible to form through-holes with high edge precision, so by forming the through-holes obtained by the present invention in a part of a wafer, it is possible to detect the amount of light passing through the through-holes and perform alignment during the formation of semiconductor devices. You can get great results by using it to do this.

[Brief explanation of the drawing]

1 to 5 show the steps of an embodiment of the method of the present invention. In the figure, Si is a semiconductor substrate, A is a region corresponding to a through hole of a predetermined size, B is an etching window surrounding region A, and W is an etching window formed on the back surface.

Claims (1)

[Claims] 1 A process of forming an oxide film on both sides of a semiconductor substrate, a process of forming a window surrounding an area corresponding to a through hole of a predetermined size in the oxide film on the surface of the semiconductor substrate, and a process of forming an oxide film on both sides of the semiconductor substrate, and forming a window surrounding a region corresponding to a through hole of a predetermined size, and applying the semiconductor to the semiconductor substrate through the window. A process of diffusing impurities that is less corroded by etching than the substrate, a process of forming a window at a corresponding position to a window formed on the back surface of the semiconductor substrate, and an etching solution that is more dependent on the crystal direction than the window formed on the back surface. 1. A method for forming a through hole in a semiconductor substrate, the method comprising the steps of etching by etching and removing an oxide film formed on both sides of the semiconductor substrate.