JPH04223331A - Semiconductor device - Google Patents

Abstract

PURPOSE:To enable a through hole for electrically connecting the surface side electrode with the rear side electrode of a semiconductor substrate such as monolithic microwave IC, etc., to be easily made by etching step. CONSTITUTION:The through hole measuring patterns 3 are provided on the electrodes 1, 2 in the terminal side opening part 6 to make the through hole 5. Through these procedures, the timing of the through hole etching termination of a semiconductor substrate can be assured thereby enabling the defective timing due to the insufficient or excessive etching step to be avoided.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device using a compound semiconductor, and more particularly to a semiconductor device having a structure in which through holes extending between both surfaces of a compound semiconductor substrate can be formed with good reproducibility.

0002

[Prior Art] Conventionally, in monolithic microwave integrated circuits (hereinafter abbreviated as MMIC) using GaAsFETs and the like as active elements, one of the methods for connecting a grounding electrode to the ground plane of a package, etc. is to use wire bonding for grounding. There is something to do. However, this method has the drawback that the inductance component of the bonding wire degrades the RF characteristics.

[0003] Therefore, the structure shown in FIG. 10 is used for the purpose of reducing the inductance component. This is GaA
A through hole 5 is formed which faces the front side electrode 1 formed on the front side of the S substrate 4 and penetrates between the front and back surfaces of this substrate 4, and by metallizing the through hole 5 and the back side of the GaAs substrate 4. The structure is such that the front side electrode 1 and the back side electrode 10 on the back side of the GaAs substrate are electrically connected to each other. According to this structure, it is possible to directly ground the package or the like when mounting it on the ground plane, and it is possible to reduce the inductance component. The steps of forming the above-mentioned through holes are shown in cross-sectional views for each step.

First, as shown in FIG. 11, a front side electrode 1 is formed on the front side of a GaAs substrate by vapor deposition or the like. Next, as shown in FIG. 12, the GaAs substrate 4 is thinned from the back side by lapping to obtain a GaAs substrate 4 of a predetermined thickness, and then selective dry etching or wet etching is performed on the GaAs substrate 4 from the back side, and the surface A substrate through hole 5 reaching the side electrode 1 is provided. Then, metal is vapor-deposited and plated from the back side to form the back side electrode 10, as shown in FIG.
As shown in FIG. 3, a structure is completed in which the front side electrode 1 and the back side electrode 10 are connected to the front side electrode 1 through the substrate through hole 5.

[0005]

Problems to be Solved by the Invention There are the following problems in confirming the end point of etching in the above process. The end point of the etching process is confirmed by visually checking the through hole 5 from the back side using a microscope. It is difficult to determine the end point of the etching process by visual inspection, and it may be mistaken as etching completion even though there is insufficient etching, resulting in a decrease in chip yield, or in cases where the grounding impedance becomes excessive and degrades high frequency characteristics. was there. The grounding impedance becomes excessive when the opening diameter of the portion where the through hole and the surface electrode contact becomes too large. Excessive etching may cause the opening to protrude beyond the surface electrode, reducing the appearance yield, or in extreme cases, the peripheral portion of the via hole electrode may be etched, resulting in a significant deterioration of mechanical strength. [Structure of the invention]

[0006]

[Means for Solving the Problems] A semiconductor device of the present invention includes:
A semiconductor substrate having a through hole reaching from one main surface to the other surface, a layer formed on one main surface of the semiconductor substrate with a part thereof facing the through hole, and an edge extending from the through hole side. a front-side electrode whose portion is visible; a back-side electrode formed in a layer on the other surface of the semiconductor substrate; and an electrode between which the back-side electrode and the front-side electrode are conductively connected using the through hole. A semiconductor device comprising a connecting means. As a modified example, a semiconductor device is provided in which a front-side electrode having an unevenness that is visible from the through-hole side is used instead of a front-side electrode whose edge is visible from the through-hole side.

[0007]

[Operation] The present invention provides a pattern for measuring the diameter of the through hole on the electrode at the terminal end when forming the through hole.
When checking in the etching process, it is possible to visually check the pattern and determine when the etching has finished.

[0008]

Embodiments Examples of the present invention will be described below with reference to FIGS. 1 to 9. Components that are the same as those of the conventional example are given the same reference numerals. FIG. 1 is a cross-sectional view of a semiconductor device according to the present invention,
Pattern 3 for measuring through hole diameter at the edge of surface side electrode 1 or 2
is formed.

FIG. 2 is a sectional view taken along line AA' in FIG. For the surface side electrode 1, in order to form a dimension measurement pattern, as an example, AuGe was applied to the shape of the densely shaded area in the figure at 2000A, followed by P.
t was selectively deposited at 300A. The front side electrode 2 has Ti/Pt/Au deposited on the missing portion of 1 and the upper surface of 1. The edges of the front-side electrodes 1 and 2 form a measurement pattern 3, and in the example of FIG. 2, the length of the straight line portion at the boundary between the front-side electrodes 1 and 2 is 10 μm. FIG. 3 shows the line BB' in FIG.
FIG. 2 is a cross-sectional view of FIG. 1 taken along a line. However, the back side electrode 10 is excluded. 6 is the opening of the through hole.

FIG. 4 shows a modification of the present invention. There is a pattern of an insulating film 7 in contact with the GaAs substrate 4, and a front side electrode 1 is formed on the cutout portion and the upper surface of the insulating film 7. Insulating film 7
The boundary between the surface-side electrode 1 and the surface-side electrode 1, that is, the edge of the surface-side electrode forms a measurement pattern 3.

Next, a method for creating the above structure is shown in cross-sectional views of each step in FIGS. 5 to 8. Thickness about 4 as shown in Figure 5
A photoresist film 8 is formed on the upper surface of the GaAs substrate 4 with a thickness of 00 μm.
is applied, and this foresist film is patterned in the shape of a pattern for through-hole diameter measurement. Next, AuGe/Pt is vapor-deposited at 2000 A/300 A, respectively, and a front-side electrode 1 in the shape of a measurement pattern is formed by lift-off.

[0012] Next, Ti/Pt/Au are vapor-deposited on top of this at 1000A/500A/8000A (FIG. 6).
. Next, the GaAs substrate 4 is lapped from the back side, and approximately 1
Make it 50 μm thick. Next, as shown in FIG. 7, a photoresist pattern 9 having openings is provided in the area where the through holes are to be formed on the back side. Next, as shown in FIG. 8, reactive ion etching (hereinafter abbreviated as RIE) is performed to form a through hole 5, and the photoresist pattern 9 is removed. FIG. 9 shows this state as viewed from the back side of the substrate.

In the process of forming the through holes in the above structure, if the etching does not reach the front side electrodes 1 and 2, the through hole diameter measurement pattern 3 will not be recognized. When the etching reaches the surface-side electrode, the through-hole diameter measurement pattern 3 can be visually recognized, and it can be determined from this pattern whether the surface-electrode side through-hole diameter is small, appropriate, or large compared to a predetermined value. By using this through-hole diameter measurement pattern 3, it is possible to know the through-hole diameter during the process, stop etching at an appropriate point, and obtain through-holes with an appropriate diameter. next,
Once the back side electrode 10 is formed, electrical connection with the front side electrodes 1 and 2 can be obtained, resulting in the state shown in FIG. 1.

The process of this embodiment prevents poor conductivity between the front side electrode 1 and back side electrode 10 due to insufficient etching when forming the through hole, excessive impedance, and poor appearance around the front side electrode 1 due to excessive etching. This can be prevented and the manufacturing yield of semiconductor devices can be improved. In the above embodiments, the edges of the through-hole diameter measuring electrodes were formed using different electrode materials. As another example, a concave portion in the shape of a pattern for measuring the diameter of a through hole is formed on the surface side of the GaAs substrate 4. To form this recessed portion, a commonly used photoresist and a technique such as wet etching or dry etching are used. AuGe/Pt and Ti/Pt/Au are deposited on the surface side of the GaAs substrate 4 on which the concave pattern is formed. As a result, the surface side electrode AuGe in contact with the GaAs substrate 4
/Pt becomes the uneven shape of the pattern for measuring the diameter of the through hole. Therefore, if the GaAs substrate 4 is etched from the back side to form a through hole as in the first embodiment, the uneven pattern of the surface electrode can be visually recognized when the through hole reaches the surface electrode. The end point of the through-hole forming etching can be easily determined based on this uneven pattern.

The edge pattern 3 of the through-hole diameter measuring electrode shown in FIGS. 2, 3, and 4 is merely an example, and the pattern is not limited to this. Of course, other shapes may be used as long as the pattern allows the pore diameter to be measured and allows electrical connection between the front and back electrodes.

[0016]

[Effects of the Invention] As described above, according to the present invention, it is possible to reliably determine when through-hole etching of a semiconductor substrate is completed, prevent defects due to insufficient etching or excessive etching, and manufacture MMICs and the like with high yield. be able to.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view illustrating a semiconductor device of the present invention.

[Figure 2]

FIG. 1 is a cutaway view taken along the line AA′ of FIG.

[Figure 3]

It is a BB' cutaway view of FIG. 2.

[Figure 4]

FIG. 3 is a modified example.

FIG. 5 is a cross-sectional view illustrating the manufacturing process of the semiconductor device of the present invention.

FIG. 6 is a cross-sectional view illustrating the manufacturing process of the semiconductor device of the present invention.

FIG. 7 is a cross-sectional view illustrating the manufacturing process of the semiconductor device of the present invention.

FIG. 8 is a cross-sectional view illustrating the manufacturing process of the semiconductor device of the present invention.

FIG. 9 is a plan view illustrating the manufacturing process of the semiconductor device of the present invention.

FIG. 10 is a cross-sectional view illustrating a conventional semiconductor device.

FIG. 11 is a cross-sectional view illustrating the manufacturing process of a conventional semiconductor device.

FIG. 12 is a cross-sectional view illustrating the manufacturing process of a conventional semiconductor device.

[Explanation of symbols]

1, 2... Surface side electrode 3... Measurement pattern 4...... GaAs substrate 5...... Through hole 6...... Opening 7... Insulating film 8...... Photoresist 9...... Photoresist Pattern 10……
… Back side electrode

Claims (2)

[Claims] 1. A semiconductor substrate having a through hole reaching from one main surface to the other surface, a layer formed on one main surface of the semiconductor substrate with a part thereof facing the through hole, and A front side electrode whose edge is visible from the through hole side, a back side electrode formed in a layered manner on the other side of the semiconductor substrate, and this back side electrode and the front side electrode are connected using the through hole. A semiconductor device comprising inter-electrode connection means for conducting conductive connection. 2. A semiconductor substrate having a through hole reaching from one main surface to the other surface, a layer formed on one main surface of the semiconductor substrate with a part thereof facing the through hole, and From the through-hole side, a front-side electrode having visible irregularities, a back-side electrode formed in a layered manner on the other surface of the semiconductor substrate, and the back-side electrode and the front-side electrode are connected using the through-hole. A semiconductor device comprising inter-electrode connection means for conducting conductive connection.