JP2002237588A - Method and apparatus for manufacturing power semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing power semiconductor device, with which reduction of the number of steps for patterning both sides of a semiconductor substrate can be realized and cost reduction is realized. SOLUTION: The method comprises the steps of applying a resist on the front surface of the semiconductor substrate, holding the substrate at a prescribed position, aligning a first mask on the front surface of the substrate, exposing the front surface with the first mask and a projection lens, developing this to form a pattern and targets on the front surface, applying a resist on the rear surface of the semiconductor substrate, holding the substrate at a prescribed position, aligning a second mask on the rear surface by using the targets, exposing the rear surface by using the second mask and the projection lens, and developing the substrate to form a pattern on the rear surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a power semiconductor device, and more particularly to a method of forming a pattern on both surfaces of a semiconductor substrate.

[0002]

2. Description of the Related Art GTO used for controlling a large current
(Gate Turn-Off Thyristor)
For example, a power semiconductor such as that described above has a pattern formed on both surfaces of a 6-inch semiconductor substrate to constitute one chip.

In forming such a double-sided pattern, as shown in FIG. 3A, first, a resist 3 "is applied on an oxide film 2" formed on the surface of a wafer 1 and baked. Thereafter, the coating is similarly applied to the back surface. After baking this, the upper and lower masks 1 held by the upper and lower mask holders 9 ′ and 9 ″ by the mistaken microscope 13 using a double-sided batch exposure aligner as shown in FIG.
0 ', 10 "alignment and numbering tape 1
Fixing by directly contacting the wafer with 2,
Expose both sides simultaneously. This is developed, baked, and then subjected to both-side etching to produce a target 5 'for alignment on both sides as shown in FIG. 3 (c). Then, a pattern 4 ″ on each surface is formed in accordance with the target as shown in FIGS. 3 (d) and 3 (e).

However, in this target forming step, a resist 3 "is applied to the surface of the wafer 1 and baked, and then turned upside down in the course of transport, and the resist 3" is applied and baked on the back surface in the same manner as the front surface. When the wafer 1 is transported, damage such as scratches and dirt occurs on the resist. Further, since the warpage of the wafer 1 and the venting of the mask cannot be controlled, a pattern requiring higher precision cannot be formed at the same time as the formation of the target, and the cost is reduced by reducing the number of steps. It was difficult.

[0005]

As described above, in the conventional method for forming a double-sided pattern of a power semiconductor, the number of steps could not be reduced, and it was difficult to reduce the cost.

Accordingly, the present invention is to provide a power semiconductor device manufacturing method and a power semiconductor device manufacturing apparatus which can eliminate such conventional disadvantages, reduce the number of steps, and reduce costs. It is the purpose.

[0007]

According to the present invention, there is provided a method of manufacturing a power semiconductor device, comprising: applying a resist to a surface of a semiconductor substrate; holding the semiconductor substrate at a predetermined position;
A step of aligning a first mask on the surface of the semiconductor substrate, a step of exposing the surface of the semiconductor substrate via the first mask and a projection lens, and a step of developing the exposed surface of the semiconductor substrate. Forming a pattern and a target on the surface of the semiconductor substrate, applying a resist to the back surface of the semiconductor substrate, holding the semiconductor substrate upside down at a predetermined position, and using the target Aligning a second mask on the back surface of the substrate, exposing the back surface of the semiconductor substrate via the second mask and a projection lens,
Developing the exposed back surface of the semiconductor substrate to form a pattern on the back surface of the semiconductor substrate.

The power semiconductor device manufacturing apparatus according to the present invention includes a mask for transferring an element pattern disposed on the back side of the semiconductor substrate, a projection lens also disposed on the back side of the semiconductor substrate, Monitoring means arranged on the front side of the semiconductor substrate for monitoring a target formed on the surface of the semiconductor substrate; means for adjusting the mask on the back side of the semiconductor substrate by the monitoring means; the mask and the projection lens Means for exposing the back surface of the semiconductor substrate through the substrate.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS.

[0010] As shown in FIG.
The surface is treated in a steam atmosphere at 900 ° C. to form oxide films 2 and 2 ′. Next, as shown in FIG. 1 (b), a photoresist 3 is applied on the oxide film 2 on the surface, and after mask alignment, exposure and development are performed with ultraviolet rays to form a pattern 4 as shown in FIG. 1 (c). . At this time, the target 5 is also formed at the same time.

Next, after a photoresist 3 'is applied on the oxide film 2' on the back surface, the wafer 1 is mounted on a wafer chuck 6 with the back surface facing upward, as shown in the exposure apparatus of FIG. A part of the wafer chuck 6 is formed of glass, and the position of the mask 10 held by the mask holder 9 by the target 5 on the surface is adjusted using the CCD 8 installed below the glass part 7. Then, as shown in FIG. 1D, exposure and development are performed through a 1: 1 projection lens 11 as shown in FIG.
A pattern 4 'on the back surface is formed as shown in FIG. In this manner, the power semiconductor device is formed by performing predetermined patterning on the front surface and the rear surface and packaging.

According to such a method, three steps of resist coating, exposure, and development for separately producing a target can be reduced, and cost can be reduced.

Further, since a non-contact projection system in which light is exposed through a 1: 1 projection lens is used, occurrence of defects due to contact can be suppressed. Furthermore, since a CCD is used for monitoring, automation is also possible.

In this embodiment, an exposure apparatus for producing a target and a pattern on the front surface is not particularly specified, but it may be produced using the same apparatus as that for the back surface pattern. Further, mask alignment may be performed using a scope instead of the CCD.

[0015]

According to the present invention, there are provided a method of manufacturing a power semiconductor device and an apparatus for manufacturing a power semiconductor device, which can reduce the number of steps in patterning both surfaces of a semiconductor substrate and reduce the cost. can do.

[Brief description of the drawings]

FIG. 1 is a view showing a manufacturing process of the present invention.

FIG. 2 is a view showing an exposure apparatus of the present invention.

FIG. 3 is a diagram showing a conventional manufacturing process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer 2, 2 ', 2 "oxide film 3, 3', 3" Photoresist 4, 4 ', 4 "Pattern 5, 5' Target 6 Wafer chuck 7 Glass part 8 CCD 9, 9 ', 9" Mask holder 10, 10 ', 10 "mask 11 Projection lens 12 Numbering tape 13 Mistake microscope

Claims (2)

[Claims] A step of applying a resist to the surface of the semiconductor substrate; a step of holding the semiconductor substrate at a predetermined position; a step of aligning a first mask on the surface of the semiconductor substrate; Through the projection lens
Exposing the semiconductor substrate surface, developing the exposed semiconductor substrate surface to form a pattern and a target on the semiconductor substrate surface, applying a resist to the back surface of the semiconductor substrate, Holding the semiconductor substrate at a predetermined position in a state where the semiconductor substrate is turned over, positioning the second mask on the back surface of the semiconductor substrate using the target, and positioning the semiconductor via the second mask and the projection lens. A method for manufacturing a power semiconductor device, comprising: exposing a back surface of a substrate; and developing a pattern on the back surface of the semiconductor substrate by developing the exposed back surface of the semiconductor substrate. A mask for transferring an element pattern disposed on the back side of the semiconductor substrate, a projection lens also disposed on the back side of the semiconductor substrate, and a target formed on the front side of the semiconductor substrate. Monitoring means arranged on the front side of the semiconductor substrate for monitoring, means for adjusting the mask on the back surface of the semiconductor substrate by the monitoring means, and exposing the back surface of the semiconductor substrate via the mask and the projection lens Means for manufacturing a power semiconductor device, comprising: