JP2011035334A - Semiconductor device - Google Patents

Abstract

An object of the present invention is to simultaneously improve material filling properties, suppress wire flow, and improve heat dissipation of a package.
Filling a material by sealing the periphery of a wire with a sealing material having a small filler filling amount, and sealing the whole including the resin with a sealing material having a large filler filling amount. It is possible to simultaneously improve the performance, suppress the wire flow, and improve the heat dissipation of the package.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor device in which a semiconductor element and a bonding wire are sealed with resin.

  As a structure for electrically connecting a semiconductor element on which an integrated circuit is formed and a substrate, there are a wire bonding structure and a flip chip structure. A semiconductor device is formed by embedding these structures with a sealing material. In particular, in the wire bonding structure, when packaging is performed using a sealing material containing a large amount of a filler in consideration of heat dissipation efficiency, high pressure is applied to the wire, resulting in defects due to wire flow and poor connection with the electrode. There is a problem that occurs. In order to improve the fluidity of the sealing material, it is effective to reduce the amount of filler filled in the sealing material. Therefore, Patent Document 1 takes a method of reducing the pressure on the wire by taking a two-layer structure of a resin-cured inner layer and an outer layer and reducing the amount of filler in the inner layer, that is, the material in contact with the wire. Yes. In addition, with respect to the problem of poor connection with an electrode, in Patent Document 2, in a structure in which semiconductor elements are stacked, an underfill is injected between a first-stage element and a substrate after wire bonding, thereby temporarily underlining. Even if the fill reaches the electrode on the substrate side, a connection failure does not occur.

  On the other hand, in recent years, the amount of heat generated by the chip has been increased along with the improvement of the degree of integration of LSI, and there has been a demand for improving the heat dissipation of the sealing material. For improvement in heat dissipation, the type and filling amount of the filler are changed, for example, the heat dissipation is improved by increasing the amount of the filler (for example, see Patent Document 3).

JP-A-8-162573 JP 2005-191229 A JP 2008-106181 A

However, in recent semiconductor devices, further improvement in heat dissipation has been demanded.
In order to solve the above-described problems, the semiconductor device of the present invention aims to simultaneously improve the material filling property, suppress the wire flow, and improve the heat dissipation property of the package.

  In order to achieve the above object, a semiconductor device of the present invention includes a semiconductor element mounting substrate including a first electrode, a semiconductor element mounted on the semiconductor element mounting substrate and including a second electrode, and the first device. A wire connecting the electrode and the second electrode, a first cured resin layer made of a first sealing material provided on at least a part of the periphery of the wire, the semiconductor element, and the wire And a second sealing material having a higher filler filling rate than the first sealing material for resin-sealing the semiconductor element mounting surface of the semiconductor element mounting substrate including the first cured resin layer. The first sealing material has a higher fluidity than the second sealing material, and the second sealing material is the first sealing material. It is characterized by higher heat dissipation.

  Further, the viscosity of the first sealing material is 1.0 Pa · s or more and 30 Pa · s or less, and the thermal conductivity of the second sealing material is 1.0 w / m · k or more and 5.0 w / m. -It is preferable to set it as k or less.

Moreover, it is preferable that the filler filling rate of said 1st sealing material is 5 to 40 wt%.
Moreover, it is preferable that the filler filling rate of said 2nd sealing material is 60 to 95 wt%.

Further, it is preferable that at least a part of the semiconductor element is exposed from the first sealing material, and the exposed surface is in contact with the second sealing material.
Further, it is preferable that the second electrode is formed around the exposed surface.

Moreover, it is preferable that at least one of the first electrode or the second electrode is covered with the first sealing material.
Moreover, it is preferable that both the first electrode and the second electrode are covered with the first sealing material.

Moreover, it is preferable that the first sealing material is filled from the wire to a region extending from the wire to the semiconductor element mounting substrate and the semiconductor element.
Moreover, it is preferable that corners formed by the semiconductor element mounting substrate and the semiconductor element are filled with the first sealing material.

Moreover, it is preferable that the first sealing material is filled in a region adjacent to the wire in all directions parallel to the wire.
Moreover, it is preferable that a corner portion of the semiconductor element is exposed from the first sealing material, and an exposed surface is in contact with the second sealing material.

Further, it is preferable to use the first sealing material as a die bond for bonding the semiconductor element to the semiconductor element mounting substrate.
Moreover, it is preferable that the first sealing material used as the die bond protrudes from the semiconductor element to be bonded.

  In addition, it is preferable to form grooves radially around the semiconductor device and in the region around the semiconductor device, in the region where the second sealing material of the semiconductor element mounting substrate is sealed. .

  As described above, it is possible to simultaneously realize improvement in material filling, suppression of wire flow, and improvement in heat dissipation of the package.

  As described above, resin filling with a sealing material with a small filler filling amount around the wire and resin sealing with the sealing material with a large filler filling amount improves the filling of the material. In addition, it is possible to simultaneously suppress the wire flow and improve the heat dissipation of the package.

Schematic showing the structure of the semiconductor device of the present invention Schematic which shows the mode of sealing material filling of the electrode periphery in the semiconductor device of this invention Schematic which shows the mode of the sealing material filling of the semiconductor element periphery in the semiconductor device of this invention Schematic explaining the manufacturing method of the semiconductor device of this invention Schematic explaining the manufacturing method of the semiconductor device of this invention Schematic which shows the resin material filling method in the manufacturing method of the semiconductor device of this invention

First, features of the semiconductor device of the present invention will be described with reference to FIG.
FIG. 1 is a schematic view showing the structure of a semiconductor device of the present invention, showing a cross-sectional view and a plan view in order to clarify the sealing region, and the plan view shows the internal structure of the cured resin layer in perspective. Yes.

  In the semiconductor device of the present invention, as shown in FIG. 1, the semiconductor element 3 is mounted on one surface of a semiconductor element mounting substrate 4 on which the semiconductor element 3 is mounted, and an electrode 7 a of the semiconductor element 3 is connected to the semiconductor element via a wire 5. A semiconductor device that is connected to the electrode 7b of the mounting substrate 4 and in which only the semiconductor element mounting substrate surface side on which the semiconductor element 3 is mounted is sealed with a cured resin layer such as a sealing material, the filler filling amount Filling and curing at least a part of the periphery of the wire 5 such as the upper part of the wire 5 and the lower part of the wire 5 and curing the sealing material 1 with the sealing material 2 having a larger filler filling amount than the sealing material 1 It is characterized by having a structure of covering the entire surface including the packaging. By filling only the peripheral part of the wire 5 such as the wire 5 and the lower part of the wire 5 with the sealing material 1 whose flowability is improved by reducing the filler filling rate, the wire flow at the time of introducing the sealing material 2 is effectively performed. In addition, after the sealing material 1 is cured, the entire surface of the sealing region of the semiconductor element mounting substrate 4 that is not filled with the sealing material 1 is filled with the sealing material 2 having a high heat dissipation property. 5 Since the entire surface other than the periphery can be resin-sealed with the sealing material 2 having high heat dissipation, the area where the sealing material 2 is in contact with the sealing material 1 and the semiconductor element 3 can be increased, and the entire package It becomes possible to remarkably improve heat dissipation.

  Here, the fluidity which does not damage a wire can be secured by adjusting the filler filling rate so that the viscosity of the sealing material 1 is 1.0 to 30 Pa · s. The filler filling rate of the sealing material 1 needs to be 5 w% to 40 w%, and more preferably about 40 w%. If the filler filling rate is less than 5 w% and the viscosity is less than 1.0 Pa · s, the viscosity is too low to make it difficult to hold the sealing resin 1 around the wire 5, and the filler filling rate is made larger than 40 w%. This is because when the viscosity exceeds 30 Pa · s, the viscosity increases, and the flow of the wire 5 or the discharge failure from the coating machine occurs. Moreover, sufficient heat dissipation can be ensured by adjusting the filler filling rate so that the thermal conductivity of the sealing material 2 is 0.2 to 0.7 w / m · k. For this, the filler filling rate of the sealing material 2 needs to be 60 w% to 95 w%, and more preferably about 95 w%. If the filler filling rate is less than 60 w% and the thermal conductivity is less than 0.2 w / m · k, the difference in thermal conductivity with the sealing material 1 is small, so that sufficient heat dissipation efficiency cannot be secured, and the filler filling rate is 95 w. This is because if the thermal conductivity is larger than 0.7% and the thermal conductivity is larger than 0.7 w / m · k, the fluidity is too small to cause voids in the package.

  As the filler, alumina, silica, AlN, BN, MgO, ZnO or the like can be used, and it is preferable to use alumina from the viewpoints of specific gravity affecting the dispersibility, thermal conductivity, cost, filling properties, and the like. .

Hereinafter, the detailed configuration will be described with reference to FIGS.
2 is a schematic view showing a state of filling a sealing material around an electrode in the semiconductor device of the present invention, and FIG. 3 is a schematic view showing a state of filling a sealing material around a semiconductor element in the semiconductor device of the present invention. 3 (b) is a cross-sectional view taken along line B in FIG. 3 (a).

  In the semiconductor device, in the structure in which the wire 5 and the wire lower part of the sealing material 1 are filled, the sealing material 1 is filled so as to cover at least one of the electrode on the element side or the semiconductor element mounting substrate side with which the wire 5 contacts. Is preferred. 2B and 2C show cross-sectional views taken along the straight line A in FIG. As shown in FIG. 2 (b), if the sealing material 1 is not filled between the electrodes 7a, 7b and the wire 5, and the sealing material 2 cannot wrap around and the gap 10 remains, it is included inside. As the air expands and contracts repeatedly, the pressure concentrates on the wire, causing damage. Further, the wire 5 may be deformed or damaged when the sealing material 2 wraps around. Therefore, as shown in FIG. 2 (c), by filling the sealing material 1 so as to completely eliminate the gap below the wire, the wire can be prevented from being damaged and an air layer having a low thermal conductivity can be formed as much as possible. This can improve the heat dissipation of the package. More preferably, the heat dissipation can be further improved by adopting a structure in which the sealing material 1 is filled so as to cover both the electrode 7a on the element side and the electrode 7b on the semiconductor element mounting substrate side.

  In each of the above semiconductor devices, as shown in FIG. 1, it is preferable that the space 8 below the wire is completely filled with the sealing material 1 up to the corner formed by the semiconductor element 3 and the semiconductor element mounting substrate 4. As shown in FIG. 1, the sealing material 1 fills the sealing material 1 not only around the wire 5 but also into the portion in contact with the semiconductor element 3 and suppresses the generation of voids in this space. The element 3 can be reinforced and damage to the wire can be prevented, and the heat dissipation of the package can be further improved by eliminating the air layer as much as possible around the electrodes 7a and 7b.

  In each of the semiconductor devices described above, it is preferable that a part of the surface of the semiconductor element 3 is exposed when the sealing material 1 is filled and cured, and the sealing material 2 is sealed so as to cover the exposed surface. As shown in FIG. 1, the sealing material 2 and the semiconductor element 3 are brought into direct contact with, for example, the center 9 on the upper surface, so that the sealing material 2 with high heat dissipation directly conducts heat generated from the semiconductor element 3 to the outside of the package. It is possible to improve the heat dissipation of the entire package. Particularly preferably, the exposed part of the surface is an internal region of the formation region of the upper surface electrode 7 a provided in the vicinity of the periphery of the surface of the semiconductor element 3. Thereby, at least the periphery of the electrode 7a is filled with the sealing material 1 to prevent the wire 5 from being deformed or damaged, and the heat dissipation can be improved by bringing the other surface of the semiconductor element 3 into contact with the sealing material 2. it can.

  In each of the above semiconductor devices, it is preferable to fix the semiconductor element 3 between the semiconductor element 3 and the semiconductor element mounting substrate 4 by using the sealing material 1 as a die bond for bonding the semiconductor element 3 to the semiconductor element mounting substrate 4. As shown in FIG. 1, by using the sealing material 1 as a die bond, the lower surface and the side surface of the semiconductor element 3 are sealed with the same material, and deformation of the semiconductor element 3 itself due to a difference in thermal stress is suppressed. It is considered that the same material can be used and the cost can be reduced. Furthermore, since the filling property is good, the air layer due to the unfilled voids can be eliminated as much as possible, and the heat dissipation property of the package can be improved. More preferably, when the interface between the semiconductor element 3 and the semiconductor element mounting substrate 4 is viewed from the upper surface side, it is preferable that the sealing material 1 used as a die bond protrudes outside the semiconductor element 3 (FIG. 3A). ). As shown in FIG. 3C, when the sealing material 1 does not protrude, when the sealing material 2 is filled, the sealing material 2 reaches the semiconductor element 3 in the portion where the wire 5 is not present. However, it is difficult to fill the corners where the semiconductor element 3 and the semiconductor element mounting substrate 4 are in contact. However, as shown in FIG. 3D, when there is an overhang 12 of the sealing material 1, when the material reaches the semiconductor element 3, the flow of the encapsulating material 2 is made upward along the overhang 12. Moreover, the filling of the sealing material 2 becomes smooth and the generation of voids can be suppressed. Thereby, the tact time at the time of filling can be shortened, and the heat dissipation as the whole package can be improved.

  In each of the semiconductor devices described above, the sealing material 1 is filled on both sides of the periphery of the wire 5 with respect to the adjacent direction of the wire 5, and the structure 13 made of the sealing material 1 is provided on the side surface of the wire 5. It is preferable. As shown in FIG. 3E, when the sealing material 1 is not filled on the side surface of the wire 5, the filling property of the sealing material 2 on the side surface of the wire 5 is poor, and a void may be generated. Therefore, as shown in FIG. 3F, by filling the both sides of the wire 5 with the sealing material 1, the flow of the sealing material 2 can be made smooth and the filling property can be improved. Thereby, the tact at the time of filling can be shortened and the heat dissipation as the whole package improves.

  In each of the semiconductor devices described above, it is preferable that the corners 11 at the four corners of the surface of the semiconductor element 3 are not filled with the sealing material 1 and the corners 11 are directly brought into contact with the sealing material 2. As shown in FIG. 3B, since the sealing material 1 exposes the corner 11 of the semiconductor element 3, the sealing material 2 with high heat dissipation and the semiconductor element 3 are in direct contact with each other. The heat dissipation can be remarkably improved.

  In each of the semiconductor devices described above, it is preferable to cut a groove 6 on the surface of the semiconductor element mounting substrate 4 as shown in FIG. The groove 6 is provided at least in a region where the semiconductor element mounting substrate 4 and the sealing material 2 are in contact with each other, the groove formed in the outer periphery of the sealing material 2 forming region, and the semiconductor element 3 mounted in the sealing material 2 forming region. It consists of grooves formed radially from the region in the outer circumferential direction. Since the fluidity of the sealing material 2 is low, filling defects such as voids may occur. However, the fluidity of the sealing material 2 can be ensured by cutting the grooves 6. Further, burrs may be generated around the sealing material 2, but by forming the groove 6 so as to surround the sealing material 2, it is possible to suppress the sealing material 2 from spreading out around the groove 6. Thus, the generation of burrs can be suppressed. As a result, the waste of the sealing material 2 is reduced, the tact time is shortened, and the surface area where the semiconductor element mounting substrate 4 and the sealing material 2 come into contact is increased, thereby further improving the heat dissipation from the sealing material 2. You can also.

Next, a specific method for manufacturing the semiconductor device is illustrated with reference to FIGS.
4 and 5 are schematic views for explaining a method of manufacturing a semiconductor device according to the present invention, which includes a plan view and a cross-sectional view along a straight line C. FIG. FIG. 6 is a schematic view showing a resin material filling method in the semiconductor device manufacturing method of the present invention.

The sealing materials 1 and 2 used here are as follows.
Sealing material 1: CV5314PAX (manufactured by Panasonic Electric Works)
Filler filling rate 40wt%
Sealing material 2: High heat dissipation sealing material
Filler filling rate 95wt%
First, in order to mount the semiconductor element 3 on the semiconductor element mounting substrate 4, as shown in FIG. 4A, the sealing material 1 is protruded from the semiconductor element 3 formation region of the semiconductor element mounting substrate 4 as an appropriate amount as a die bond. After printing or coating and mounting the semiconductor element 3, it is cured. In this case, the material is supplied by a screen printer or a coating device.

  Next, as shown in FIG. 4B, the electrode 7 b on the semiconductor element mounting substrate 4 and the electrode 7 a on the upper surface of the semiconductor element 3 are connected by the wire 5. Supply of the wire 5 is performed using a wire bonding apparatus.

  Next, as shown in FIG. 5A, the sealing material 1 is applied on the semiconductor element mounting substrate 4, the semiconductor element 3, and the like around the wire 5 and in the vicinity of the wire 5. At this time, the non-contact coating machine S-920 (manufactured by Asymtec) is used as the coating machine, and the coating is performed between the wires 5. The coating is performed until it reaches under the wire 5 and above the wire 5. Thereafter, the sealing material 1 is applied to the portion where the wires 5 are not present at the interface between the semiconductor element mounting substrate 4 and the semiconductor element 3 by the above-described coating machine and cured under predetermined curing conditions.

  Finally, as shown in FIG. 5B, the sealing material 2 is filled in the sealing material 2 application region on the semiconductor element mounting substrate 4 including the semiconductor element 3 and the sealing material 1. As a filling method, a vacuum printing method or a transfer molding method is used depending on the form of the sealing material 2. When the sealing material 2 is a liquid thermosetting resin, a vacuum printing method is used, and when it is a tablet, a transfer molding method is used.

In particular, when the transfer molding method is used, as shown in FIG. 6, the sealing material 2 is injected from the gate port 16 and the filling proceeds as shown by the arrows.
Note that the die bond material and the sealing material 1 may not be the same material.

  INDUSTRIAL APPLICABILITY The present invention can simultaneously improve material filling properties, suppress wire flow, and improve heat dissipation of a package, and is useful for a semiconductor device or the like in which a semiconductor element and a bonding wire are sealed with a resin.

DESCRIPTION OF SYMBOLS 1 Sealing material 2 Sealing material 3 Semiconductor element 4 Semiconductor element mounting substrate 5 Wire 6 Groove 7a Electrode 7b Electrode 8 Space 9 Center part 10 Space | gap 11 Corner | angular part 12 Projection 13 Structure 16 Gate port

Claims (15)

A semiconductor element mounting substrate comprising a first electrode;
A semiconductor element mounted on the semiconductor element mounting substrate and provided with a second electrode;
A wire connecting the first electrode and the second electrode;
A first cured resin layer made of a first sealing material provided on at least a part of the periphery of the wire;
The filler filling rate is higher than that of the first sealing material for resin-sealing the semiconductor element mounting surface of the semiconductor element mounting substrate including the semiconductor element, the wire, and the first resin cured body layer. A second cured resin layer made of the sealing material, and the first sealing material has higher fluidity than the second sealing material, and the second sealing material The semiconductor device is characterized in that it has higher heat dissipation than the first sealing material.   The viscosity of the first sealing material is 1.0 Pa · s to 30 Pa · s, and the thermal conductivity of the second sealing material is 1.0 w / m · k to 5.0 w / m · k. The semiconductor device according to claim 1, wherein:   3. The semiconductor device according to claim 1, wherein a filler filling rate of the first sealing material is 5 w% or more and 40 wt% or less.   4. The semiconductor device according to claim 1, wherein a filler filling rate of the second sealing material is 60 w% or more and 95 wt% or less.   5. The device according to claim 1, wherein at least a part of the semiconductor element is exposed from the first sealing material, and the exposed surface is in contact with the second sealing material. Semiconductor device.   The semiconductor device according to claim 5, wherein the second electrode is formed around the exposed surface.   The semiconductor device according to claim 1, wherein at least one of the first electrode and the second electrode is covered with the first sealing material.   8. The semiconductor device according to claim 7, wherein both the first electrode and the second electrode are covered with the first sealing material.   The semiconductor device according to claim 1, wherein the first sealing material is filled from the wire to a region extending from the wire to the semiconductor element mounting substrate and the semiconductor element.   The semiconductor device according to claim 9, wherein a corner formed by the semiconductor element mounting substrate and the semiconductor element is filled with the first sealing material.   11. The semiconductor device according to claim 9, wherein the first sealing material is filled in a region adjacent to the wire in all directions parallel to the wire.   12. The semiconductor according to claim 1, wherein a corner portion of the semiconductor element is exposed from the first sealing material, and an exposed surface is in contact with the second sealing material. apparatus.   13. The semiconductor device according to claim 1, wherein the first sealing material is used as a die bond for bonding the semiconductor element to the semiconductor element mounting substrate.   14. The semiconductor device according to claim 13, wherein the first sealing material used as the die bond protrudes from the semiconductor element to be bonded.   Grooves are formed radially around the region to be sealed and around the semiconductor device in a region of the semiconductor element mounting substrate where the second sealing material is sealed. The semiconductor device according to claim 1.

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