JP7299768B2 - Semiconductor device, substrate for mounting semiconductor element, and manufacturing method thereof - Google Patents

Description

The present invention relates to a semiconductor device in which minute electronic circuit components such as semiconductor elements are mounted on a substrate.

When mounting electronic parts such as chip resistors and semiconductor elements such as semiconductor diodes and LEDs on a board, the parts to be mounted such as electronic parts and semiconductor elements are mounted on the electrodes of the board with solder sandwiched between them. After that, a procedure is used in which the solder is melted by heating, and the electrodes and the mounting component are joined with the solder. At this time, a method of heating the substrate with a hot plate or the like is used to heat the solder.

Further, Patent Literature 1 proposes a method of heating a metal material by induction heating when bonding a die having solder on its back surface to a metal material provided on a substrate made of a non-metal material. . According to induction heating, the metal material is heated in a concentrated manner, and the non-metal material is heated only by heat conduction from the metal material, so that the heat damage to the non-metal material can be reduced.

JP-A-2005-244228

In the bonding of semiconductor elements using induction heating as in Patent Document 1, it is desired to improve the heating efficiency of metal materials, reduce damage to non-metal materials, and improve the reliability of semiconductor devices. there is In particular, when semiconductor elements are joined using induction heating, it is desired to improve the heating efficiency of the semiconductor element mounting area (die pad) among metal materials.

A first object of the present invention is to provide a configuration of a semiconductor device capable of efficiently heating a minute die pad by induction heating.

A second object of the present invention is to provide a metal material that has a role other than wiring, such as a semiconductor device having a substantially ring-shaped metal pattern that has a role of regulating wetting and spreading of a sealing resin that covers a semiconductor element. It is an object of the present invention to provide a configuration of a semiconductor device capable of efficiently heating a die pad by induction heating even in a semiconductor device having

To achieve the above object, a semiconductor device according to a first aspect of the present invention has a semiconductor element and a nonmetallic substrate on which the semiconductor element is mounted, and a metal pattern is arranged on the surface of the substrate. there is The metal pattern has a die pad to which a semiconductor element is die-bonded by an adhesive layer, and an annular pattern, and the die pad and the annular pattern are connected.

According to the present invention, by using the phenomenon that the inventors discovered that a current is likely to flow through an annular pattern due to induction heating, the annular pattern is heated by induction heating, and the heat is led to the die pad. A minute die pad can be efficiently heated by adopting a discontinuous configuration in the circumferential direction in which current does not flow in a discontinuous annular pattern.

(a) to (d) are a top view, a cross-sectional view taken along line A-A', a bottom view, and a perspective view of the semiconductor device of Embodiment 1. FIG. FIG. 4 is an explanatory diagram showing a state in which induction heating is performed according to the first embodiment; (a) to (c) are a top view of a semiconductor device of Embodiment 2, a top view with a cavity mounted thereon, and a perspective view with a cavity mounted thereon, respectively. FIG. 12 is a top view of the semiconductor device of Embodiment 3; (a) and (b) are a top view of the semiconductor device of Embodiment 4, and a top view in which a cavity is mounted. (a) to (g) are diagrams showing manufacturing steps of the semiconductor device of Embodiment 4. FIG. (a) and (b) are a top view and a perspective view of a semiconductor device of Reference Example 5. FIG.

A semiconductor device according to one embodiment of the present invention will be described with reference to the drawings.

<<Embodiment 1>>
The semiconductor device of Embodiment 1 will be described with reference to FIGS. 1(a) to 1(d). 1A to 1D are a top view, a cross-sectional view taken along line AA', a bottom view and a perspective view of the semiconductor device, respectively.

The semiconductor device shown in FIG. 1 includes a semiconductor element 1 and a substrate 2 on which the semiconductor element 1 is mounted.

A surface of the substrate 2 is provided with a metal pattern 3 including a die pad 3a and an annular pattern 3b. A semiconductor element 1 is die-bonded to the die pad 3a with an adhesive layer 4. As shown in FIG. The die pad 3a and the annular pattern 3b are connected. Specifically, the die pad 3a is entirely disposed inside the annular pattern 3b, and the die pad 3a and the annular pattern 3b are connected by a connecting pattern 3c also formed on the substrate 2 surface. The number of connecting patterns 3c is two or more, and when two or more portions of the die pad 3a are connected to the annular pattern 3b, the die bonding temperature of the die pad 3a can be made uniform, which is preferable. In addition, connecting the connecting pattern 3c to the annular pattern 3b at equal intervals in the circumferential direction and connecting to the die pad 3a at equal intervals on the outer periphery of the die pad 3a uniformly transfers the heat of the annular pattern 3b to the die pad 3a. It is preferable because it can

Here, the semiconductor element 1 is a light-emitting element, and the size of the element is, for example, 1 mm square. Therefore, the size of the die pad 3a is also a very small circular shape that is slightly larger than the light-emitting element 1 so that the light-emitting element 1 can be mounted. The annular pattern 3b is ring-shaped and equidistant from the die pad 3a in the circumferential direction so as to surround the die pad 3a.

The adhesive layer 4 is, for example, AuSn. The metal pattern 3 is formed of a metal plating layer, has a thickness of, for example, 70 μm, and has a surface layer of, for example, an Au layer.

A dome-shaped sealing resin 5 that seals the light emitting element 1 is mounted in a region surrounded by the annular pattern 3b. The edge shape of the dome-shaped sealing resin 5 matches the outer edge shape of the annular pattern 3b. Specifically, the sealing resin 5 in which the outer edge of the annular pattern 3b is aligned with the edge of the dome-shaped sealing resin 5 is a resin through which the light emitted from the light emitting element 1 is transmitted, such as a silicone resin. It is composed of

The substrate 2 is made of a non-metallic material such as a resin substrate (eg, glass epoxy). Under the die pad 3a, a copper core 6 that penetrates the substrate 2 is arranged. electrically connected. A back electrode 7 electrically connected to the lower surface of the copper core 6 and a wiring pattern 8 for supplying power to the back electrode 7 are arranged on the back side of the substrate 2 .

Electrode pads 9 are arranged inside the annular pattern 3 b on the upper surface of the substrate 2 . A through electrode 10 that is electrically connected to the electrode pad 9 and penetrates the substrate 2 is arranged under the electrode pad 9 . A rear surface electrode 11 electrically connected to the through electrode 10 and a wiring 12 for supplying power to the rear surface electrode 11 are arranged on the rear surface side of the substrate 2 .

The light emitting element 1 has a back electrode and a top electrode. The back electrode is connected to the die pad 3a by the adhesive layer 4 described above, and the top electrode is connected to the electrode pad 9 by the bonding wire 13.

Thus, by supplying a current from the wirings 8 and 12 to the back electrodes 7 and 11, the current can be supplied to the light emitting element 1 to emit light. The emitted light passes through the dome-shaped sealing resin 5 and is emitted.

A die pad 15 for a Zener diode is arranged so as to overlap a part of the annular pattern 3b, and the lower surface electrode of the Zener diode 14 is joined by an adhesive layer (not shown). A top electrode of the Zener diode 14 is connected to the electrode pad 9 by a bonding wire 16 .

Since the annular pattern 3b is connected to the die pad 3a by the connecting pattern 3c, it has the same potential as the die pad 3a. Therefore, the Zener diode 14 is a circuit connected in parallel with the light emitting element 1 and functions as a protection element for the light emitting element 1 .

<Manufacturing method>
A method for manufacturing the semiconductor device of Embodiment 1 will be described.

A substrate 2 having a metal pattern 3 including a die pad 3a, an annular pattern 3b, and a connecting pattern 3b is prepared. At this time, for example, AuSn paste is applied as an adhesive layer to the Zener diode die pad 15 having the annular pattern 3b, and the Zener diode 14 is mounted.

Next, as shown in FIG. 2, the substrate 2 is mounted on the support base 21 indicated by the stand 22 of the induction heating apparatus, and the tip of the high frequency converging nozzle 24 is arranged in the vicinity of the copper core 6 . In this state, when a high-frequency current is supplied to the coil 23 from the high-frequency power supply 25, the coil 23 generates a high-frequency magnetic field. be.

Since the die pad 3a is arranged above the copper core 6 and the annular pattern 3b is arranged around the die pad 3a so as to surround the die pad, the high frequency magnetic field is supplied to the die pad 3a and the annular pattern 3b. The die pad 3a has a small size and a skin effect, so that it is difficult for electric current to flow through it and it is difficult for it to be heated. On the other hand, since the annular pattern 3b has an annular shape and is larger in size than the die pad 3a, a current circulating along the annular ring easily flows and is easily heated.

As a result, when the temperature of the annular pattern 3b rises, the heat of the annular pattern 3b is conducted to the die pad 3a through the connecting pattern 3c, thereby heating the die pad 3a. At this time, two connecting patterns 3c are arranged, and the connection positions to the die pad 3a are symmetrical (180 degrees), so heat is conducted to the die pad 3a from two symmetrical locations, and the die pad 3a is uniformly heated. .

By heating the die pad 3a, the AuSn paste that is the adhesive layer 4 is heated to form an AuSn eutectic, and the die pad 3a and the back electrode of the light emitting element 1 are AuSn eutectic bonded.

At this time, since the Zener diode die pad 15 on the annular pattern 3b is also heated at the same time, the Zener diode 14 and the die pad 15 are also AuSn eutectic bonded.

Next, the upper electrode of the light emitting element 13 and the electrode pad 9 are connected by the bonding wire 13 . Also, the upper electrode of the Zener diode 14 and the electrode pad 9 are connected by a bonding wire 16 .

Next, when uncured sealing resin (silicone resin) is dropped inside the annular pattern (on top of the light emitting element 1), the uncured sealing resin spreads out and reaches the edge of the outer periphery of the annular pattern. Then, due to the surface tension, it will not spread further and stop. After that, by curing the sealing resin, it is possible to form the sealing resin 5 rising in a dome shape.

As described above, in the present embodiment, by utilizing the phenomenon that the inventors discovered that a current easily flows through the annular pattern 3b by induction heating, the annular pattern 3b is heated by induction heating, and the heat is transferred to the die pad 3a. It is possible to efficiently heat the very small die pad 3a by guiding the heat up to. Thereby, the light emitting element 1 can be mounted on the die pad 3a.

When a semiconductor device was actually manufactured by the manufacturing method of this embodiment, the adhesive layer after bonding did not contain voids, had high bonding strength, and was in a good bonding state with low electrical resistance.

Since the annular pattern 3b has an empty inner region, the die pad 3a can be arranged inside, and the mounting density can be improved compared to the case of using a planar pattern filled up to the center.

In addition, by arranging the die pad 3a in the center of the annular pattern 3b and arranging the wiring on the back surface side using a copper core or a through electrode, it is possible to reduce the restrictions on the routing of the wiring and increase the degree of freedom in design. .

Moreover, as described above, the annular pattern 3b also has the advantage that it can be used also as a pattern for fixing the sealing resin by surface tension.

In this embodiment, a light-emitting element is used as the semiconductor element 1, but it is of course possible to use a semiconductor element that does not emit light, or a minute element such as a chip resistor or a chip capacitor as the element 1. FIG.

Further, the substrate 2 is not limited to a resin substrate obtained by impregnating glass fiber such as glass epoxy with resin such as epoxy resin, and a resin substrate made of only resin such as polyimide, or a ceramic substrate can also be used. be.

The adhesive layer 4 can be composed not only of an AuSn eutectic material, but also of solder other than AuSn, or a sintered bonding material using nanoparticles such as Au.

<<Embodiment 2>>
The semiconductor device of Embodiment 2 will be described with reference to FIGS. 3(a) to 3(c).

The semiconductor device of Embodiment 2 has the same configuration as that of the device of Embodiment 1, but differs from Embodiment 1 in that the shape of the annular pattern 3b is a rectangular ring instead of a circle.

As in the semiconductor device of the first embodiment, the semiconductor device of the second embodiment utilizes the phenomenon that an electric current easily flows through the annular pattern 3b by induction heating, heats the annular pattern 3b by induction heating, and transfers heat to the die pad. By leading to 3a, the minute die pad 3a can be efficiently heated. Thereby, the light emitting element 1 can be mounted on the die pad 3a.

In addition, as shown in FIG. 3B, the cavity 31 may be arranged on the annular pattern 3b. Further, the inside of the cavity 31 may be sealed with a resin 32 as shown in FIG. 3(c).

<<Embodiment 3>>
A semiconductor device of Embodiment 3 will be described with reference to FIG.

The semiconductor device of FIG. 4 has a plurality of die pads 3a, and differs from the first embodiment in that they are directly connected to the annular pattern 3b without intervening a connecting pattern. The electrode pad 9 is arranged in the center of the annular pattern 3b.

The semiconductor device of Embodiment 3 can simultaneously heat a plurality of die pads 3a and bond a plurality of semiconductor elements 1 at the same time.

Other configurations, manufacturing steps and effects are the same as those of the semiconductor device of the first embodiment.

<<Embodiment 4>>
The semiconductor device of Embodiment 4 will be described with reference to FIGS. 5(a) and 5(b).

The semiconductor device of FIG. 5(a) is implemented in that a part of the die pad 3a is arranged so as to overlap the annular pattern 3b, and that the annular pattern 3b is cut and divided together with the substrate 2. Different from form 1. Other configurations are the same as those of the first embodiment. It is also possible to mount a cavity 31 around the substrate 2 and seal the inside of the cavity 31 with a resin 32 as shown in FIG. 5(b).

The manufacturing process of the semiconductor device of FIG. 5(b) will be described with reference to FIGS. 6(a) to 6(g).

First, as shown in FIG. 6A, a substrate for mounting a semiconductor element is prepared in which a plurality of metal patterns 3 are arranged vertically and horizontally so that a die pad 3a is partially overlapped with an annular pattern 3b. A substrate for mounting a semiconductor element is configured as an aggregate substrate for collectively manufacturing a plurality of semiconductor devices. Cutting lines are provided between the die pads 3a for cutting into a plurality of semiconductor devices in a later process. The individual annular patterns 3b are arranged over the adjacent substrates for semiconductor devices so as to overlap the cutting lines.

Next, as shown in FIG. 6B, a cavity 31 provided with a plurality of openings is mounted on the substrate 2. Next, as shown in FIG. A die pad 3 a is positioned in the center of the opening of the cavity 31 .

As shown in FIG. 6C, an adhesive layer is arranged by applying AuSn paste or the like on the die pad 3a, and the semiconductor element 1 is mounted. The annular pattern 3b is heated by induction heating, heat is conducted to the die pad 3a, and the AuSn is melted to bond the semiconductor element 1 to the die pad 3a. This step is as described in the first embodiment. The plurality of annular patterns 3b may be heated by supplying a high-frequency magnetic field collectively, or may be heated one by one.

As shown in FIG. 6(d), the bonding wire 13 connects the upper surface electrode of the semiconductor element 1 and the adjacent annular pattern 3b.

As shown in FIG. 6E, the opening of the cavity 31 is sealed with a sealing resin 32. Then, as shown in FIG.

Finally, as shown in FIG. 6(f), the cavity 31 and the substrate 2 are cut at four sides around the opening to separate them. Thereby, the annular pattern 3b on the substrate 2 is cut as shown in FIG. 6(g), and the semiconductor device shown in FIG. 5(b) can be manufactured.

<< Reference Example 5>>
A semiconductor device of Reference Example 5 will be described with reference to FIGS.

Unlike Embodiments 1 to 4, Reference Example 5 is based on the phenomenon that electric current easily flows through the annular pattern due to induction heating, and by configuring the annular pattern so that current does not flow, the minute die pad can be efficiently heated. do.

That is, as shown in FIGS. 7A and 7B, the semiconductor device has a semiconductor element 1 and a substrate 2 on which the semiconductor element 1 is mounted. The surface of the substrate 2 is provided with a die pad 3a and an annular pattern 3b arranged so as to surround the die pad 3a. The semiconductor element 1 is die-bonded to the die pad 3a with an adhesive layer.

Here, in this reference example , slits 71 are formed in the annular pattern 3b to form a discontinuous shape in the circumferential direction.

As a result, when a high-frequency magnetic field is applied as shown in FIG. 2 to induction-heat the die pad 3a, the circular pattern 3b is discontinuous in the circumferential direction, so that no circulation current flows and the supplied high-frequency magnetic field is applied to the die pad 3a. can be supplied by concentrating only on Therefore, the die pad 3a can be heated by induction heating, the adhesive layer can be melted, and the semiconductor element 1 can be bonded to the die pad 3a.

The width of the slit 71 is set so that the uncured resin 5 does not flow out.

As a result, even when the uncured sealing resin 5 is dripped and spread by a process similar to that of the first embodiment, it is stopped by the surface tension at the outer edge of the annular pattern 3b without being affected by the slit 71 and sealed. The stopper resin 5 can be piled up in a dome shape.

Other configurations and other manufacturing processes are the same as those of the first embodiment.

When a semiconductor device was actually manufactured by the manufacturing method of this reference example 5, the adhesive layer after bonding did not contain voids, had high bonding strength, and was in a good bonding state with low thermal resistance.

The semiconductor device of each embodiment described above can be used as an LED lighting device or the like.

Three samples, first to third, were prepared for the substrate 2 having the metal pattern 3, and the heating state of the die pad 3a on the substrate 2 was evaluated.

The first sample corresponds to the first embodiment, and the second sample corresponds to the fifth reference example . The third sample has a configuration in which the metal pattern 3 of Reference Example 5 is changed without the slits 71 .

For evaluation of the heating state, AuSn paste for confirming the temperature rise on the metal pattern 3 was applied to appropriate locations on the metal pattern 3, a high-frequency magnetic field was applied to each sample with a high-frequency coil, and the AuSn paste was applied to each sample. The melting state of the paste was confirmed.

In the first sample, the AuSn paste was applied to the die pad 3a, the intersection of the annular pattern 3b and the connecting pattern 3c, the electrode pad 9, and the die pad 15 for Zener diode.

In the second sample, AuSn paste was applied on the die pad 3a and the annular pattern 3b.

In the third sample, AuSn paste was applied on the die pad 3a and the annular pattern 3b.

As a result, in the first sample, when a high-frequency magnetic field with a high-frequency electric power of 2 kW·s was applied, the AuSn paste on the die pad 3a, the intersection of the annular pattern 3b and the connection pattern 3c, and the Zener diode die pad 15 Although it melted, the AuSn paste on the electrode pad 9 did not melt.

In the second sample, when a high-frequency magnetic field with a high-frequency electric power of 4.05 kW·s was applied, the AuSn paste on the die pad 3a was melted, but the AuSn paste on the annular pattern 3b was not melted.

In the third sample, when a high-frequency magnetic field with a high-frequency electric power of 1.95 kW·s was applied, the AuSn paste on the die pad 3a did not melt, but the AuSn paste on the annular pattern 3b melted.

Further, the first to third samples were confirmed by changing the output of the high frequency coil and the application time.

In the first sample, it was confirmed that the AuSn paste on the annular pattern 3b first melted and then the AuSn paste on the die pad 3a melted. It is assumed that the annular pattern 3b is heated and the heat is transferred to the die pad 3a.

In the second sample, only the flux component was evaporated at a power of 2.49 kW·s, and AuSn was not melted, but melting was confirmed at a power of 4.05 kW·s. It is considered that since the annular pattern 3b has the slit 71, it no longer functions as a secondary coil and the die pad 3a is preferentially heated.
Thus, it was confirmed that the AuSn paste on the die pad 3a of the first sample melted at a power of 2 kW·s, and the AuSn paste on the die pad 3a of the second sample melted at a power of 4.05 kW·s.

On the other hand, in the third sample, the AuSn paste on the die pad 3a did not melt even when heating was performed by increasing the amount of high-frequency power until the substrate 2 around the annular pattern 3b was discolored. When the output was increased until the melted, the annular pattern 3b was peeled off.

From these, it was confirmed that the first sample and the second sample were configured to efficiently heat the die pad 3a. Also, it was confirmed that the first sample has a configuration capable of heating the die pad 3a more efficiently than the second sample.

DESCRIPTION OF SYMBOLS 1... Semiconductor element (light emitting element), 2... Substrate, 3... Metal pattern, 3a... Die pad, 3b... Annular pattern, 3c... Connection pattern, 4... Adhesive layer, 5... Sealing resin, 6... Copper core, 7... , Back electrode 8 Wiring pattern 9 Electrode pad 10 Through electrode 11 Back electrode 12 Wiring pattern 13 Bonding wire 14 Zener diode 15 Die pad for Zener diode 16 Bonding wire

Claims (13)

Having a semiconductor element and a substrate made of non-metal on which the semiconductor element is mounted,
A metal pattern is arranged on the surface of the substrate,
The metal pattern has a die pad to which the semiconductor element is die-bonded by an adhesive layer and an annular pattern, the die pad and the annular pattern are connected , and the annular pattern is continuous in the circumferential direction. A semiconductor device characterized by: 2. The semiconductor device according to claim 1, wherein when a high-frequency magnetic field is supplied to said substrate by an induction heating device, said annular pattern is heated by flowing a current circulating along said annular pattern. heat is conducted to the die pad connected to the annular pattern. 2. The semiconductor device according to claim 1, wherein said die pad is entirely arranged in a region inside said annular pattern, and a connection pattern for connecting said die pad and said annular pattern is arranged between said die pad and said annular pattern. A semiconductor device characterized by: Having a semiconductor element and a substrate made of non-metal on which the semiconductor element is mounted,
A metal pattern is arranged on the surface of the substrate,
the metal pattern has a die pad to which the semiconductor element is die-bonded by an adhesive layer and an annular pattern, wherein the die pad and the annular pattern are connected;
The semiconductor device according to claim 1, wherein the die pad is arranged so as to partially overlap the annular pattern. 4. The semiconductor device according to claim 3 , wherein the semiconductor element is a light-emitting element, a dome-shaped resin sealing the light-emitting element is mounted inside the annular pattern, and the dome-shaped resin A semiconductor device, wherein the edge shape matches the shape of the annular pattern. 6. The semiconductor device according to claim 3 , wherein said connecting pattern connects two or more of said die pads to said annular pattern. 7. The semiconductor device according to claim 6, wherein the connecting pattern is connected to the annular pattern at equal intervals in the circumferential direction. a substrate made of non-metal;
and a metal pattern formed on the substrate surface,
The metal pattern has a die pad for mounting a semiconductor element and an annular pattern, the die pad and the annular pattern are connected , and the annular pattern is continuous in a circumferential direction. substrate. a substrate made of non-metal;
and a metal pattern formed on the substrate surface,
The metal pattern has a die pad for mounting a semiconductor element and an annular pattern, the die pad and the annular pattern being connected,
The substrate includes a plurality of die pads for mounting the semiconductor element,
the substrate includes a cutting line between the plurality of semiconductor element mounting die pads;
A substrate for mounting a semiconductor element, wherein the annular pattern is arranged so as to overlap the cutting line. a step of mounting a semiconductor element on the die pad of a substrate made of a non-metal on which a metal pattern including a die pad and a metal pattern connected to the die pad and including a circumferentially continuous annular pattern is formed, with an adhesive layer sandwiched therebetween;
a step of irradiating at least the annular pattern with a high-frequency magnetic field for induction heating, conducting the heat generated in the annular pattern to the die pad, heating the adhesive layer, and bonding the die pad and the semiconductor element. A method of manufacturing a semiconductor device, characterized by: 11. The method of manufacturing a semiconductor device according to claim 10, wherein after the step of bonding the semiconductor element, an uncured sealing resin is dropped inside the annular pattern, and the edge of the sealing resin is A method of manufacturing a semiconductor device, further comprising a step of curing after wetting and spreading until the annular pattern is reached. 10. A cut semiconductor device mounting substrate obtained by cutting the semiconductor device mounting substrate according to claim 9 along said cutting line. 10. The semiconductor element mounting board according to claim 9 is cut along the cutting line, and the semiconductor element mounting board is die-bonded by an adhesive layer to the semiconductor element mounting die pad of the cut semiconductor element mounting board. a semiconductor device comprising: a semiconductor element;

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