JPH1041470A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a power supply device small. SOLUTION: A control system semiconductor element 4 is formed on a surface layer of a semiconductor area 3 isolated by a dielectric isolation area 2 of a dielectric isolation substrate 1, and a power system element 6 is formed on a rear side 5 of the dielectric isolation substrate 1. The control system semiconductor element 4 and the power system element 6 are connected by a bonding wire 7. A power system element 9 which cannot be formed on the dielectric isolation substrate 1 is formed on, e.g. a dielectric isolation substrate 8 and connected to the control system semiconductor element 5 by a bump 10. The power system elements 6, 9 are thin film elements formed by using the thin film forming technology and passive elements such as coil or capacitors. Furthermore, the diameter of the bonding wire 7 is selected usually to be about 20μm and smaller than the thickness of the bump whose thickness is 50μm or over.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC-DC comprising various electronic parts formed on a semiconductor substrate, an insulator substrate or the like.
The present invention relates to a power supply device such as a converter.

[0002]

2. Description of the Related Art In a conventional power supply device, a connection between a control semiconductor element and a power element has been performed by using a bump technique. FIG. 4 is a main part configuration diagram of a conventional power supply device. The control system semiconductor element 4 is formed on the surface layer of the semiconductor substrate 8, and the power system element 9 is formed on each of the two semiconductor substrates 8, for example. The control system semiconductor element 4 is an active element such as a MOS device, for example, and the power system element 9 is a passive element such as a coil and a capacitor. The control system semiconductor element 4 and the power system element 9 are connected by bumps. The bumps are projections of solder for wiring and are not shown, but are formed by digging pinholes in the semiconductor substrate 8 and filling the metal, and the bumps are connected to the surface of the semiconductor substrate 8. ing.

[0003]

However, in the conventional power supply device, the power element is made thinner by using a thin film forming technique. However, the control semiconductor element and the power element are separated from each other by a dielectric isolation substrate. Such elements are connected to each other by using a bump technique. In connection by this bump, since the bump itself has a thickness of about 0.5 mm, it was difficult to reduce the size of the device.

An object of the present invention is to solve the above-mentioned problems and to provide a compact power supply.

[0005]

In order to achieve the above object, in a power supply device having a control system semiconductor element and a power system element, a control system semiconductor element is formed on a front surface side of a dielectric isolation substrate, and is formed on a back surface side. A thin film power system element is formed, and the control semiconductor element and the thin film power system element are connected by bonding wires. The thin-film power system element may be any one of a thin-film coil, a laminated thin-film capacitor, and a trench-type thin-film capacitor. Further, it is preferable that the control system semiconductor element and the thin-film power system element are connected by a bonding wire via a conductive thin film formed on a package.

By replacing the conventional bump connection with the bonding wire connection, the thickness can be reduced and the size of the device can be reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a main part of a first embodiment of the present invention. Dielectric isolation region 2 of dielectric isolation substrate 1
A control semiconductor element is formed on the surface layer of the semiconductor region 3 on the front side (this region may be surrounded by a dielectric isolation region shown in the drawing and a dielectric isolation region on the side surface not shown in the figure). 4 is formed, and a power-related element 6 is formed on the back surface (back surface 5) of the dielectric isolation substrate 1. The control system semiconductor element 4 and the power system element 6 are connected by bonding wires 7. A power element 9 that cannot be formed on the dielectric isolation substrate 1
Is formed, for example, on a semiconductor substrate 8 and the control system semiconductor element 4
And the bump 10. The power system elements 6 and 9 are thin film elements formed by using a thin film forming technique, and the structure is shown in FIG. MOS is used as the control system semiconductor element 4
Active devices such as MOS devices such as FETs and IGBTs and bipolar transistors. Also, the power system element 6,
9 is a passive element such as a coil and a capacitor. In addition, by forming the control system semiconductor element 4 and the power system element 6 on the front surface side and the back surface side of the dielectric isolation substrate 1, the thickness can be reduced by half as compared with the case where the semiconductor element is formed on an individual semiconductor substrate. Further, the diameter of the bonding wire 7 is about 50 μm to 100 μm, so that the
An insulating film for electric insulation is formed on top with a thickness of about 1 μm,
When the bonding wire 7 is provided thereon, 0.5
The wiring portion can be made thinner than when wiring is performed with bumps having a height of about mm.

FIG. 2 is a structural view of a principal part of a thin-film element. FIG. 2A is a sectional view of a principal part of a thin-film coil, FIG. 2B is a sectional view of a principal part of a multilayer thin-film capacitor, and FIG. () Shows a sectional view of a main part of the trench type thin film capacitor. In FIG. 1A, an insulating film 21 and a magnetic film 2 are formed on the back side of a dielectric insulating substrate 1.
2, insulating film 23, conductive film 24 serving as a coil, insulating film 25,
The magnetic film 26 and the insulating film 27 are respectively laminated to form the thin film coil 11. The insulating film 27 is for protection. Further, a control semiconductor element 4 is formed on a surface layer of the semiconductor region on the surface side of the dielectric isolation substrate 1. FIG.
In the above, the insulating film 28, the conductive film 29 and the insulating film 30 are laminated on the back side of the dielectric isolation substrate 1 to form the multilayer thin film capacitor 12. One electrode of the capacitor is the back surface of the dielectric isolation substrate 1, and the other electrode is a conductive film 29. Note that the insulating film 30 is for protection. In FIG. 1C, a groove 3 is formed in a semiconductor region 32 on the back surface of the dielectric isolation substrate 1.
1, an insulating film 33 is formed on the surface of the groove 31,
A conductive film 34 is formed on the insulating film 33 and the conductive film 3
4, the trench 31 is filled, the surface is flattened, and an insulating film 35 is formed on the conductive film 34. The conductive film 34 and the dielectric separation substrate 1
A capacitor is formed on the back surface of. With this trench type structure, a capacitor having a small area and a large capacity can be formed. The insulating film 35 is for protection.

FIG. 3 is a block diagram of a main part of a second embodiment of the present invention. The difference from FIG. 1 is that a conductive film (not shown) formed on the package 14 and the power element 6 are fixed, and the conductive film and the control semiconductor element 4 are connected by bonding wires 7. .

[0010]

According to the present invention, in a power supply device such as a DC-DC converter, a power system element such as a thin film coil or a thin film capacitor is formed by using a thin film forming technique on the back surface of a dielectric separation substrate. By connecting the power system element and the control system semiconductor element formed on the surface of the dielectric isolation substrate with thin bonding wires, the thickness of the power supply device is reduced and the size of the power supply device is reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of a first embodiment of the present invention.

FIGS. 2A and 2B are structural views of a principal part of a thin film element, FIG. 2A is a sectional view of a principal part of a thin film coil, FIG. 2B is a sectional view of a principal part of a multilayer thin film capacitor, and FIG. Partial sectional view

FIG. 3 is a configuration diagram of a main part of a second embodiment of the present invention.

FIG. 4 is a main part configuration diagram of a conventional power supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric isolation substrate 2 Dielectric isolation region 3 Semiconductor region 4 Control system semiconductor region 5 Back surface 6 Power system element 7 Bonding wire 8 Semiconductor substrate 9 Power system element 10 Bump 11 Thin film coil 12 Stacked thin film capacitor 13 Trench thin film capacitor 14 Package 21 insulating film 22 magnetic film 23 insulating film 24 conductive film 25 insulating film 26 magnetic film 27 insulating film 28 insulating film 29 conductive film 30 insulating film 31 groove 32 semiconductor region 33 insulating film 34 conductive film 35 insulating film

Claims (3)

[Claims] In a power supply device having a control system semiconductor element and a power system element, a control system semiconductor element is formed on a front surface side of a dielectric separation substrate, and a thin film power system element is formed on a back surface side.
A power supply device wherein a control system semiconductor element and a thin-film power system element are connected by a bonding wire. 2. The power supply device according to claim 1, wherein the thin-film power system element is one of a thin-film coil, a laminated thin-film capacitor and a trench-type thin-film capacitor. 3. The power supply device according to claim 1, wherein the control semiconductor element and the thin-film power element are connected by a bonding wire via a conductive thin film formed on the package.