阅读说明：本技术 半导体装置和电力变换装置 (Semiconductor device and power conversion device ) 是由 海老原洪平 宫川成人 于 2018-03-08 设计创作，主要内容包括：本发明的目的在于提供一种抑制氧化物的析出来防止树脂层的剥离且可靠性高的半导体装置。本发明的半导体装置(100)具备：第二导电类型的末端阱区域(2),形成于半导体层(1b)的表层；场绝缘膜(3),被设置成延伸到比末端阱区域(2)的外周端更外周侧；树脂层,被设置成至少一部分在比场绝缘膜(3)的外周端靠外周侧的半导体层(1b)的表面上延伸；第二导电类型的浮动阱区域(7),在半导体层(1b)的表层,形成为与末端阱区域(2)分离,与场绝缘膜(3)的外周端相接且延伸到比场绝缘膜(3)的外周端更外周侧,具有浮置电位。(The invention provides a semiconductor device which suppresses the precipitation of an oxide, prevents the peeling of a resin layer, and has high reliability. A semiconductor device (100) of the present invention includes: a second conductivity type end well region (2) formed on the surface layer of the semiconductor layer (1 b); a field insulating film (3) provided so as to extend to the outer peripheral side of the outer peripheral end of the end well region (2); a resin layer provided so that at least a part thereof extends on the surface of the semiconductor layer (1b) on the outer peripheral side of the outer peripheral end of the field insulating film (3); the floating well region (7) of the second conductivity type is formed on the surface layer of the semiconductor layer (1b) so as to be separated from the end well region (2), is in contact with the outer peripheral end of the field insulating film (3), extends to the outer peripheral side of the outer peripheral end of the field insulating film (3), and has a floating potential.)

1. a semiconductor device includes:

A semiconductor substrate (1 a);

A semiconductor layer (1b) of a first conductivity type formed on the semiconductor substrate (1 a);

Surface electrodes (4, 5) provided on the surface side of the semiconductor layer (1 b);

A second conductivity type end well region (2) formed on the surface layer of the semiconductor layer (1b) so as to extend at least partially to the outer peripheral side of the outer peripheral ends of the surface electrodes (4, 5);

A field insulating film (3) provided on the surface of the semiconductor layer (1b) so as to cover at least a part of the end well region (2), extending to the outer peripheral side than the outer peripheral end of the end well region (2);

A resin layer provided in contact with the outer peripheral end of the field insulating film (3), at least a part of the resin layer extending onto the surface of the semiconductor layer (1b) on the outer peripheral side of the outer peripheral end of the field insulating film (3); and

And a floating well region (7) of a second conductivity type formed on the surface layer of the semiconductor layer (1b) so as to be separated from the end well region (2), extending to the outer peripheral side of the outer peripheral end of the field insulating film (3) in contact with the outer peripheral end of the field insulating film (3), and having a floating potential in contact with the resin layer.

2. The semiconductor device according to claim 1,

The depth of the floating well region (7) is larger than the width of a depletion layer formed from the interface between the bottom of the floating well region (7) and the semiconductor layer (1b) to the inside of the floating well region (7).

3. The semiconductor device according to claim 1 or 2,

The distance separating the inner peripheral end and the outer peripheral end of the floating well region (7) from the outer peripheral end of the field insulating film (3) is greater than the width of a depletion layer formed from the interface between the floating well region (7) and the semiconductor layer (1b) into the floating well region (7).

4. The semiconductor device according to any one of claims 1 to 3,

The resin layer includes a surface protection film (6), the surface protection film (6) is provided so as to cover a part of the surface electrodes (4, 5) and at least a part of the field insulation film (3), and is in contact with the surface of the floating well region (7),

The floating well region (7) is provided so as to extend to the outer peripheral side of the outer peripheral end of the surface protection film (6).

5. The semiconductor device according to claim 4,

The floating well region (7) is provided so as to extend to the outer peripheral end of the semiconductor layer (1 b).

6. The semiconductor device according to any one of claims 1 to 3,

The resin layer includes:

A surface protection film (6) that covers a part of the surface electrodes (4, 5) and at least a part of the field insulation film (3), and has an outer peripheral end located on the inner peripheral side of the outer peripheral end of the field insulation film (3); and

And a sealing gel provided so as to contact the surface of the floating well region (7).

7. The semiconductor device according to any one of claims 1 to 6,

The dielectric constant of the vacuum is set as epsilon₀[F/m]setting the relative dielectric constant of the semiconductor layer (1b) to be epsilon_sSetting the avalanche voltage of the semiconductor device to V_bd[V]Setting the element charge to q [ C ]]And the impurity concentration of the semiconductor layer (1b) is N_d[cm^-3]From the outer peripheral end of the end well region (2) toDistance [ cm ] of outer peripheral end of the field insulating film (3)]Is composed of

[ mathematical formula 1]

The following.

8. The semiconductor device according to any one of claims 1 to 7,

The floating well region (7) has at least one or more circumferentially separated portions in a plan view.

9. The semiconductor device according to any one of claims 1 to 8,

a plurality of terminal well regions (2) are formed so as to be separated from each other in a direction from the inner circumferential side toward the outer circumferential side.

10. The semiconductor device according to any one of claims 1 to 9,

The end well region (2) is formed so that the impurity concentration decreases from the inner peripheral side to the outer peripheral side.

11. The semiconductor device according to any one of claims 1 to 10,

The semiconductor layer (1b) is silicon carbide.

12. The semiconductor device according to any one of claims 1 to 11,

A diode is formed on the inner peripheral side of the end well region (2).

13. The semiconductor device according to any one of claims 1 to 11,

A transistor including at least 1 or more second conductivity type well regions (9) is formed on the inner peripheral side of the end well region (2).

14. A power conversion device is provided with:

A main conversion circuit having the semiconductor device according to any one of claims 1 to 13, the main conversion circuit converting an input electric power and outputting the converted electric power;

A drive circuit that outputs a drive signal for driving the semiconductor device to the semiconductor device; and

And a control circuit outputting a control signal for controlling the driving circuit to the driving circuit.

Technical Field

The present invention relates to a semiconductor device.

Background

In a vertical semiconductor device used for a power device or the like, it is known that an electric field when a reverse voltage is applied is relaxed by a depletion layer formed by a pn junction between a semiconductor layer and a guard ring region by providing a p-type guard ring region (end well region) in a so-called end region in an n-type semiconductor layer in order to secure a withstand voltage (for example, patent document 1). In the Schottky Barrier Diode (SBD) described in patent document 1, a field insulating film is provided on the semiconductor layer in the end region, and the outer peripheral end of the surface electrode is formed to overlap the field insulating film. In such a semiconductor device, a protective film of polyimide or the like is formed to protect the surface except for a partial region on a surface electrode on which wire bonding (wire bonding) is performed (for example, patent document 2). In addition, a portion where a protective film of polyimide or the like is formed may be sealed with a resin such as a gel.

Patent document 1: japanese patent laid-open No. 2012 and 195324

Patent document 2: japanese patent laid-open publication No. 2013-211503

Disclosure of Invention

Problems to be solved by the invention

in a semiconductor device provided with a protective film of polyimide or the like or a sealing gel, particularly when used in a state of high humidity, there are cases where: the gel, polyimide, or the like contains moisture, and the semiconductor layer reacts with the moisture in the region not covered with the field insulating film on the outer periphery of the semiconductor chip, thereby depositing an oxide. In such a case, there are cases where: the precipitated oxide lifts up a resin layer such as a surface protective film or a sealing gel to cause peeling, and a cavity formed by the peeling forms a leakage path, thereby causing a defect in the semiconductor chip.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a highly reliable semiconductor device in which separation of an oxide is suppressed and peeling of a resin layer is prevented.

Means for solving the problems

the semiconductor device according to the present invention includes:

A semiconductor substrate;

a semiconductor layer of a first conductivity type formed on the semiconductor substrate;

A surface electrode provided on a surface side of the semiconductor layer;

A second conductivity type end well region formed on the surface layer of the semiconductor layer so as to extend at least partially to a position outside an outer peripheral end of the surface electrode;

a field insulating film provided on a surface of the semiconductor layer so as to cover at least a part of the end well region, extending to an outer peripheral side than an outer peripheral end of the end well region;

A resin layer provided so as to contact a surface of the semiconductor layer on an outer side of an outer peripheral end of the field insulating film;

And a floating well region of the second conductivity type formed on the surface layer of the semiconductor layer so as to be separated from the end well region, in contact with the outer peripheral end of the field insulating film, extending to the outside of the outer peripheral end of the field insulating film, and having a floating potential.

ADVANTAGEOUS EFFECTS OF INVENTION

according to the semiconductor device of the present invention, it is possible to provide a highly reliable semiconductor device in which separation of an oxide in a surface portion of a semiconductor layer on the outer periphery side of a field insulating film is suppressed, and peeling of a resin layer is prevented.

The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

Drawings

Fig. 1 is a sectional view showing a semiconductor device according to embodiment 1 of the present invention.

Fig. 2 is a cross-sectional view showing a semiconductor device according to embodiment 1 of the present invention.

Fig. 3 is a cross-sectional view showing a semiconductor device according to the prior art.

Fig. 4 is a cross-sectional view showing a semiconductor device according to embodiment 1 of the present invention.

Fig. 5 is a sectional view showing a semiconductor device according to embodiment 1 of the present invention.

Fig. 6 is a cross-sectional view showing a semiconductor device according to embodiment 1 of the present invention.

Fig. 7 is a plan view showing a semiconductor device according to embodiment 1 of the present invention.

Fig. 8 is a sectional view showing a semiconductor device according to embodiment 1 of the present invention.

Fig. 9 is a sectional view showing a semiconductor device according to embodiment 1 of the present invention.

Fig. 10 is a sectional view showing a semiconductor device according to embodiment 1 of the present invention.

fig. 11 is a sectional view showing a semiconductor device according to embodiment 2 of the present invention.

Fig. 12 is a sectional view showing a semiconductor device according to embodiment 2 of the present invention.

Fig. 13 is a diagram showing a power conversion device according to embodiment 3 of the present invention.

(description of reference numerals)

1 a: a semiconductor substrate; 1 b: a semiconductor layer; 2: a terminal trap region; 3: a field insulating film; 4: a Schottky electrode; 5: an electrode pad; 6: a surface protective film; 7: a floating well region; 8: a back electrode; 9: a p-type well; 10: a high concentration p region; 11: an n-type source electrode; 12: a gate insulating film; 13: a gate electrode; 14: an interlayer insulating film; 100: a semiconductor device; 200: a semiconductor device; 1000: a power source; 2000: a power conversion device; 2001: a main conversion circuit; 2002: a drive circuit; 2003: a control circuit; 3000: and (4) loading.

Detailed Description

The embodiments are described below with reference to the drawings. The drawings are schematically illustrated, and the relationship between the size and the position of images shown in different drawings is not necessarily described accurately, and may be changed as appropriate. In the following description, the same components are denoted by the same reference numerals, and the same names and functions are assumed. Therefore, detailed description thereof may be omitted. In the present specification, the terms "up" and "covering" do not prevent the presence of an intervening object between the constituent elements. For example, the description "B provided on a" and "a covers B" includes the case where another component C is provided between a and B and the case where another component C is not provided between a and B. In the following description, terms indicating specific positions and directions such as "upper", "lower", "side", "bottom", "front", and "back" are used in some cases, but these terms are used for convenience of understanding the contents of the embodiments and are not related to the directions in actual implementation.