KR100244826B1 - A semiconductor device and method for manufacturing the same - Google Patents

Abstract

The present invention is to provide a semiconductor device which is excellent in heat dissipation and inexpensive.

The present invention includes a copper circuit pattern body (2) provided on one circumferential surface of the ceramic substrate (1), and a semiconductor pellet (6) mounted on the circuit pattern body (2). The circuit pattern body 2 is partially extended longer than the ceramic substrate 1, and the circuit pattern body 2-LEAD which is extended is functioned as an external terminal of the pellet 6. According to this structure, since the pellets 6 contact the ceramic substrate 1 only through the circuit pattern body 2 substantially, the heat dissipation of the pellets 6 is improved. Further, by increasing the circuit pattern body 2-LEAD as the external electrode terminal of the pellet 6, the increase in the number of parts can be suppressed. From this point of view, a semiconductor device which is excellent in heat dissipation and inexpensive is obtained.

Description

Semiconductor device and manufacturing method

1 shows a semiconductor device according to an embodiment of the present invention, in which FIG. 1 (a) is a plan view, and FIG. 1 (b) is a sectional view taken along the line 1b-1b in FIG.

2 is a circuit diagram showing a circuit of a semiconductor device according to one embodiment of the present invention;

FIG. 3 is a view showing a DBC substrate provided in a semiconductor device according to an embodiment of the present invention. FIG. 3A is a plan view and FIG. 3B is a line 3b-3b in FIG. 3A. According to the section,

4 is a view showing a conventional example, FIG. 4 (a) is a plan view, and FIG. 4 (b) is a sectional view taken along line 4b-4b in FIG. 4 (a),

5 is a view showing another conventional example, FIG. 5 (a) is a plan view, FIG. 5 (b) is a side view, and FIG. 5 (c) is a sectional view taken along the line 5c-5c in FIG. 5 (a). to be.

* Explanation of symbols for the main parts of the drawings

1: ceramic substrate 2: copper circuit pattern body

3: alloy layer 4: copper pattern

5: DBC substrate 6: pellet

7: conductive paste 8: bonding wire

9 molding resin 10 metal heat sink

11: high melting point brazing material 12: short circuit

[Industrial use]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly, to a semiconductor device having a power transistor pallet, a power IC, and the like, and a manufacturing method thereof.

[Traditional Technology and Problems]

Resin-sealed semiconductor devices equipped with power element ferrets, etc., have a surface inside the enclosure other than the external electrode terminal (lead) to prevent electrical short-circuits with other pellets or external heat sinks when the device is mounted and used. It is preferable that it is electrically insulated from the pellet of.

4 and 5 show conventional examples of such an insulating device.

FIG. 4 is a view showing a conventional example, and FIG. 4 (a) is a plan view showing the inside thereof, and FIG. 4 (b) is a view of FIG. 4 (b) and a line 4b-4b in FIG. 4 (a). In accordance with the cross-sectional view.

As shown in Figs. 4A and 4B, there is a conductive electrode terminal 41 (lead) obtained by using a lead frame, and part of the electrode terminal body 41 is partially enlarged in size. Equipped with bed 41-BED. The semiconductor pellet 42 is mounted on the bed 41-BED, and the semiconductor pellet 42 is fixed to the bed 41-BED by the brazing material 43 and electrically connected to the electrode terminal 41. Connected.

A pad electrode (not shown) is provided on the surface of the pellet 42, and the pad electrode is electrically connected to the electrode terminal body 41 by the bonding wire 44.

A molding resin 45 covering the pellets 42 is provided around the electrode terminal body 41, and the molding resin 45 insulates the pellets 42 from the outside. As the molding resin 45, thermoplastic resin is used, and in this example, epoxy resin.

The electrode terminal body 41 extends out from the surface of the molding resin body 45, and this exposed part becomes an external electrode terminal (external lead).

Furthermore, a metal heat sink 46 is provided on the surface opposite to the mounting surface of the bed 42-BED via the molding resin 45, and the heat sink 46 is exposed to the outside world. The heat sink 46 is attached at the time of transfer molding.

5 is a view showing another conventional example, FIG. 5 (a) is a plan view, FIG. 5 (b) is a side view, and FIG. 5 (c) is a sectional view taken along the line 5c-5c in FIG. 5 (a). to be.

For the description of the apparatus shown in FIG. 5, parts common to those of the apparatus shown in FIG. 4 are denoted with the same reference numerals, and only the other parts will be described.

As shown in Figs. 5A to 5C, there is a ceramic substrate 51, and there is a DBC (Direct Bonding Copper) substrate provided with a circuit pattern 52 made of copper on its mounting surface. A part of the circuit pattern 52 is provided with a bed 52-BED formed by partially extending its size, and the semiconductor pellet 42 is mounted on the bed 52-BED.

On the surface opposite to the mounting surface of the ceramic substrate 51, a metal heat sink 46 is provided via the brazing material 53. As shown in FIG.

On the periphery of the heat dissipation plate 46 on the DBC substrate side, a resin case 54 is adhered through the adhesive layer 55, and a gel 56 is filled in the case 54, and the semiconductor pellet 42 And the DBC substrate are each covered with a gel 56 made of silicone resin. The surface of the gel agent 56 is covered with a casting agent 57 made of thermoplastic resin. Further, a terminal holder 58 is provided on the casting agent 57, a pin-shaped electrode terminal 59 is attached to the terminal holder 58, and one end side of the electrode terminal 59 is formed of a casting agent 57 and The gel 56 penetrates and is electrically connected to the circuit pattern 52. On the other hand, the other end protrudes from the terminal holder 58 to become an external electrode terminal (external lead).

By the way, in the resin sealing semiconductor device in which the power element pellet 42 or the like is mounted, it is important to quickly release the heat generated from the pellet 42 into the atmosphere outside the apparatus. In other words, by increasing the heat dissipation, it is possible to ensure the reliability after a long time while exhibiting the specific ability of the power device.

Therefore, in the envelope of the apparatus, it is very important to increase the heat dissipation by reducing the thermal resistance value from the power element pellet 42 to the surface of the envelope.

However, in the conventional example shown in Fig. 4, the thermal resistance value is relatively large because the thermal conductivity K of the molding resin for insulation is very small. Compared with the conventional example shown in FIG. 5, it is much smaller than that of ceramics.

Further, the thickness A of the molding resin 45 covering the back surface of the lead frame 41 (electrode terminal) {see FIG. 4 (b)) can be made thin to the extent that thermal conductivity equivalent to that of ceramic is obtained from the constraints of the manufacturing technique. It is also a cause.

For example, using a sealing resin (K = 0.04W / cm ° C) having the best thermal conductivity among those currently on the market, alumina ceramic (K = 0.2W / cm ° C) having a thickness of 0.6 mm, as used in other conventional examples, may be used. In order to obtain the same thermal conductivity, the thickness must be 0.12 mm or less.

However, as mentioned above, the manufacturing limit of thickness A is 0.5 mm, and it is impossible at this time to make thickness below 0.12 mm. Moreover, the average particle diameter of the thermoplastic resin used for sealing is about 0.3 mm. For this reason, when thickness A is made narrower than 0.5 mm, a void may generate | occur | produce in any way, and may deteriorate the quality and reliability of an apparatus.

From this point of view, in the conventional example shown in FIG. 4, a heat dissipation surface is concerned.

On the other hand, the other conventional example shown in FIG. 5 is superior in terms of heat dissipation to the conventional example shown in FIG. As a result, the product becomes expensive.

For example, when comparing two conventional examples with each other, the main parts of the conventional example shown in FIG. 4 have five scores (lead frame, pellet, heat sink, wire, resin), and the other conventional examples shown in FIG. There are nine {DBC substrate, pellet, heat sink, wire, adhesive for case bonding, resin case, gel, casting, terminal holder (including terminal electrode)}.

In addition, as shown in FIG. 4, the number of assembly steps in the conventional example is four times (die bonding, wire bonding, transfer molding, external lead forming), while the other conventional example shown in FIG. 5 is six times {die bonding and wire bonding. , Heat sink mounting, terminal holder mounting, resin case mounting, resin filling}.

[Purpose of invention]

SUMMARY OF THE INVENTION The present invention has been made in view of the above point, and an object thereof is to provide a semiconductor device which is excellent in heat dissipation and inexpensive and a manufacturing method thereof.

[Configuration of Invention]

The present invention for achieving the above object includes an insulating substrate body, a conductive metal pattern body provided on one main surface of the substrate body, and a semiconductor component mounted on the conductive metal pattern body. The conductive metal pattern body is partially extended out of the substrate body, and the conductive metal pattern body which extends out of the substrate body functions as an external terminal of the semiconductor component.

(Action)

According to the present invention configured as described above, a conductive metal pattern body is provided on one main surface of the insulating substrate body, a semiconductor component is mounted on the conductive metal pattern body, and the conductive metal pattern body partially comes out longer than the substrate body. . By doing in this way, since a semiconductor component is actually contacting an insulating board | substrate only through a conductive metal pattern body, the heat dissipation of a semiconductor component is improved.

In addition, an increase in the number of parts can be suppressed by making the elongated conductive metal pattern body function as an external terminal of the semiconductor component. If the increase in the parts score is suppressed, the number of processes required for the assembly can be reduced.

EXAMPLE

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a semiconductor device according to one embodiment of the present invention, in which FIG. 1 (a) is a plan view through which the inside is viewed from an upper surface, and FIG. 1 (b) is 1b-1b in FIG. 1 (a). Sectional view along the line.

As shown in Figs. 1A and 1B, there is an insulating ceramic substrate 1, and on the mounting surface of the ceramic substrate 1, a conductive copper circuit pattern body 2 is provided. The ceramic substrate 1 is made of ceramic mainly composed of aluminum and oxygen, and the circuit pattern body 2 is made of copper or metal composed mainly of copper. An example of the ceramic is alumina (Al ₂ O ₃ ), and an alloy layer 3 of the same alloy as the ceramic is formed between the ceramic substrate 1 and the circuit pattern body 2, and the circuit pattern body 2 is formed. Is bonded to the ceramic substrate 1 by this alloy layer 3. Furthermore, on the surface opposite to the mounting surface (hereinafter referred to as the back surface), a copper pattern 4 fixed to the ceramic substrate 1 by the alloy layer 3 is similarly provided. Thereby, the DBC (Direct Bonding Copper) board | substrate 5 is comprised.

A part of the circuit pattern body 2 is provided with a bed 2-BED having a partially expanded size, and on the bed 2-BED, a power device semiconductor pellet including a power transistor or a power IC therein ( 6) is mounted. The power device semiconductor pellets 6 are fixed on the bed 2-BED by the brazing material 7 and electrically connected to the circuit pattern body 2. As the brazing material 7 for fixing the power element semiconductor pellet 6 and the bed 2-BED, a high melting point brazing material is preferably used. In this embodiment, a high melting point brazing material having a melting point of about 310 占 폚 is used.

In addition, a pad electrode (not shown) is provided on the surface of the pellet 6, and the pad electrode is electrically connected to the circuit pattern body 2 by bonding wires 8 such as gold (Au) or aluminum (Al). Is connected. A molding resin 9 is provided around the DBC substrate 5 to cover the circuit pattern 2 and the pellets 6, and the molding resin 9 insulates the pellets 6 from the outside. As the molding resin 9, a thermoplastic resin is used, and is molded into a rectangular parallelepiped shape by a transfer molding method. As a thermoplastic resin used for a present Example, it is epoxy resin, for example.

The circuit pattern body 2 partially has a portion extending longer than the ceramic substrate 1, which is indicated by the reference numeral 2-LEAD. The long portion is further exposed to the outside through the molding resin 9, and the exposed portion is functioning as an external electrode terminal (external lead).

Furthermore, in this embodiment, a metal heat sink 10 is provided on the back surface of the ceramic substrate 1, and the heat sink 10 is provided on the back surface of the ceramic substrate 1 by, for example, a high melting point solder 11. It is fixed to the copper pattern 4. The heat sink 10 is exposed to the outside world and causes heat generated by the pellets 6 to escape to the atmosphere outside the apparatus.

The above embodiment considers an example of an inverter circuit device for motor driving, and six pellets 6 are assembled in this inverter circuit device, and this circuit diagram is shown in FIG.

As shown in FIG. 2, one pellet 6 has a base terminal, a collector terminal, and an emitter terminal, and functions as one power element (bipolar transistor in this example). However, two power transistors (pipolar type), diodes, and resistors connected to Darlington are assembled therein, and integrated circuits, that is, a kind of power ICs, can drive large currents.

The inverter circuit for motor drive shown in FIG. 2 is comprised by using six pellets 6 in which the said power element or power IC was contained. Then, the six power IC pellets 6 are mounted in one enclosure, so that one resin sealing semiconductor device is provided. Therefore, the external electrode terminals exposed from the molding resin 9 have a positive power supply terminal (+), a negative power supply terminal (−), six input terminals (BU, BV, BW, BX, BY, BZ) and three There are eleven systems of output terminals U, V, and W.

Further, in Fig. 1A, a common reference numeral is given in the vicinity of the external electrode terminal in correspondence with the circuit shown in Fig. 2.

Next, the DBC board | substrate 5 which the apparatus shown in FIG. 1 has is demonstrated in more detail.

3 is a view showing a DBC substrate 5 provided in a semiconductor device according to an embodiment of the present invention. FIG. 3 (a) is a plan view and FIG. 3 (b) is 3b- in FIG. 3 (a). It is sectional drawing along the 3b line.

As shown in FIG. 3, the DBC board | substrate 5 is provided with the short circuit part 12 in the vicinity of the terminal part of the circuit pattern body 2, and forms the shape of a lead frame. In this way, the circuit pattern body 2 is formed in the form of a lead frame to enable continuous assembly.

Next, a method of assembling the apparatus shown in FIG. 1 will be described.

First, a DBC substrate 5 provided with a lead frame-shaped circuit pattern 2 as shown in FIG. 3 is prepared.

Subsequently, the pellets 6 are fixed onto the bed 2-BED provided on the circuit pattern body 2 using the high melting point solder 7 (die bonding).

Subsequently, an unillustrated pad provided on the pellet 6 and the circuit pattern body 2 are electrically connected using a bonding wire 8 such as gold (Au) or aluminum (Al) (wire bonding).

Next, using the high melting point lead dam material 11, the metal heat sink 10 is fixed on the back surface of the DBC substrate 5 (heat radiating plate fitting).

Next, a molding resin is introduced into the mold using a mold (not shown) to form a rectangular molded resin body 9 around the DBC substrate 5 (transfer molding).

Finally, the short circuit part 12 is cut off in the vicinity of the end of the circuit pattern body 2 so that it may be cut. After this cutting, the external electrode terminal is molded into a desired shape (external lead forming).

As described above, the semiconductor device according to the embodiment of the present invention can be assembled.

According to the semiconductor device according to the first embodiment, since the circuit pattern body 2 is almost in direct contact with the ceramic substrate 1, the pellets 6 are actually made of only a ceramic substrate (2) through the circuit pattern body (2). 1). Therefore, the heat dissipation property of the pellets 6 can be improved rather than the apparatus in which resin is filled under the bed for mounting pellets (refer FIG. 4).

A specific example of the effect on heat dissipation is that the thermal resistance of the conventional device was about 4 ° C./W per one power element pellet of 5 mm 2, whereas that of the device according to the first embodiment was about 1.5 ° C./W. This can be reduced to less than half.

Further, in the apparatus according to the first embodiment, the circuit pattern body 2 is partially extended out of the ceramic substrate 1, and the extended circuit pattern body 2 functions as an external terminal of the pellet 6. . By using the circuit pattern body 2 as an external electrode terminal in this way, an increase in the number of parts can be suppressed. If the increase in the parts score is suppressed, the cost of parts can be curbed.

In addition, by suppressing an increase in the number of parts, an increase in the number of assembling processes is also suppressed, thereby suppressing the manufacturing cost.

In particular, the apparatus shown in FIG. 5, that is, the apparatus having improved heat dissipation, tends to be expensive because of its high parts score.

However, in the apparatus according to the above embodiment, the score of the major components is five (DBC substrate, pellet, heat sink, wire, resin), and the number of components can be reduced by four compared with the apparatus shown in FIG.

In addition, the number of processes required for the assembly is also five times (die bonding, wire bonding, heat dissipation plate mounting, transfer molding, external lead forming), and can be reduced once again. It can be made more inexpensive from this.

Further, in the apparatus according to the first embodiment, the circuit pattern body 2 is formed in the form of a lead frame. For example, the resin sealing is continuously and collectively performed by transfer molding using a mold.

In particular, in the apparatus shown in FIG. 5, it is necessary to perform resin sealing for each product, and there is an obstacle in terms of mass productivity and workability.

In this regard, in the apparatus according to the first embodiment, assembling of the apparatus is performed continuously and collectively, mass productivity and workability are improved.

Moreover, the present invention is not limited to the above one embodiment.

For example, the material of the ceramic substrate 1 is made from alumina ceramic to aluminum nitride ceramic (AlNx), and a material layer containing a group IV element is formed therebetween to fix the aluminum nitride ceramic and the copper circuit pattern body 2. You may do so. The joining method using such a material layer is a joining method generally called an active metal joining.

Although aluminum nitride ceramics are currently more expensive than alumina ceramics or difficult to use a direct bonding method such as the DBC method, they are characterized by superior thermal conductivity than alumina ceramics. For this reason, it is useful to make the material of the ceramic substrate 1 into aluminum nitride ceramics to improve heat dissipation.

[Effects of the Invention]

As described above, the present invention provides a semiconductor device which is excellent in heat dissipation and inexpensive.

Claims (4)

A ceramic substrate made of an electrically insulating material having a relatively high thermal conductivity, A circuit pattern member having an external electrode terminal extending from the ceramic substrate, An alloy layer provided between the circuit pattern body and the ceramic substrate, the alloy layer comprising a material constituting the circuit pattern body and a material constituting the ceramic substrate. A semiconductor pellet mounted on the circuit pattern body, A copper pattern provided on the other main surface of the ceramic substrate, An alloy layer provided between the copper pattern and the ceramic substrate, the alloy layer comprising a material constituting the copper pattern and a material constituting the ceramic substrate; A heat sink mounted to the copper pattern, And a molding resin body covering the ceramic substrate on which the semiconductor pellet is mounted and the heat sink to expose the external terminal. The semiconductor device according to claim 1, wherein the circuit pattern body and the semiconductor pellet are joined by a brazing material. 3. A semiconductor device according to claim 2, wherein said solder material is selected from the group consisting of solder and a solder material containing a Group IV element of the periodic table. The alloy layer is composed of a material constituting the circuit pattern body and the ceramic substrate, the circuit pattern body is configured to have an external electrode terminal extending from the ceramic substrate substantially parallel to the one main surface of the ceramic substrate, Mounting the semiconductor pellet on a circuit pattern body formed on one main surface of the substrate by an alloy layer interposed between the circuit pattern body and the ceramic substrate, the ceramic substrate being made of a relatively thermally conductive electrical insulating material; Fixing the copper pattern on the other main surface of the ceramic substrate by an alloy layer interposed between the copper pattern and the ceramic substrate, the alloy layer being composed of a material constituting the copper pattern and the ceramic substrate, Fixing a heat sink to the copper pattern; And covering both the ceramic substrate on which the semiconductor pellet is mounted and the heat sink with an insulating material to expose external electrode terminals.