JP3249263B2 - Semiconductor package and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor package such as a plastic mold package and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable trend toward smaller, thinner, and higher-performance electronic devices, and with this trend, electronic components have rapidly become more sophisticated. This tendency is particularly strong in the field of semiconductor devices such as memories, and there is a demand for smaller, thinner, lower-cost, highly reliable semiconductor packages suitable for high-density mounting. Previously, ceramic packages were predominant as semiconductor packages, but nowadays, the demand for surface-mount type plastic mold packages that are more advantageous for high-density mounting than insertion types is increasing. There are many types of surface mount type plastic mold packages such as QFP type, SOP type, and SOJ type depending on the mounting form.

The SOJ type plastic mold package will be described with reference to FIG. In this SOJ type plastic mold package, leads 33 are arranged on the back surface side of a semiconductor element 31, and the semiconductor element 31 and the leads 33 are covered with a sealing resin 32. The semiconductor element 31 is bonded to the die pad 34 of the lead 33 with an Ag paste 37. The Al electrode 35 of the semiconductor element 31 is connected to the lead 33 by an Au wire 36. The lead 33 is made of a metal material such as copper or a 42 alloy, and leads the J-shaped external terminal 33 a to the outside of the sealing resin 32.

[0004]

However, because of the structure in which the leads 33 are bonded to one surface of the semiconductor element 31, the amounts of thermal expansion on the main surface side and the rear surface side of the semiconductor element 31 due to temperature changes are different, and the internal stress is reduced. Warpage due to the occurrence of cracks was easy to occur. For this reason, a large stress is applied to the semiconductor element 31, which causes a package crack or separation at the bonding interface of the sealing resin 32. Further, if the package becomes hot after absorbing moisture, the absorbed moisture becomes steam at the bonding interface between the back surface of the die pad 34 and the sealing resin 32 and expands. .

Further, the plastic mold package is cut off from a lead frame (not shown), and the external terminals 33a of the leads 33 are formed into a J shape by metal working. For this reason, since a large load is applied to the lead 33, the lead 33 easily falls off due to peeling at the bonding interface between the lead 33 and the sealing resin 32.

[0006] The above-mentioned problems lower productivity and hinder thinning and high-density packaging.
Further, the reliability of the semiconductor element 32 is impaired. An object of the present invention is to provide a semiconductor package having good productivity and high reliability, and a method for manufacturing the same.

[0007]

According to a first aspect of the present invention, there is provided a semiconductor package comprising a semiconductor element, leads electrically connected to electrodes of the semiconductor element, and a sealing resin covering the semiconductor element and the leads. The lead is made of a resin material having a conductive metal layer formed on the surface. And the thermal expansion of the lead
So that the coefficient and the thermal expansion coefficient of the sealing resin are equal.
The mixing ratio of the glass fibers of the glass is adjusted. In the semiconductor package according to the second aspect, the back surface of the semiconductor element is fused to the die pad surface of the resin lead having a conductive metal layer formed on the surface other than the die pad. The electrode of the semiconductor element and the conductive metal layer of the resin lead are electrically connected. The semiconductor element and the resin lead are covered with a sealing resin. Then, use resin leads and resin leads.
The thermal expansion coefficient between the pad and the sealing resin
Glass fiber between lead and die pad to be equal
Is adjusted. In the semiconductor package according to the third aspect, the main surface of the semiconductor element is directly fused to the back surface of the internal terminal of the resin lead having the conductive metal layer formed on the surface. The conductive metal layer of the resin lead is electrically connected to the electrode of the semiconductor element. The semiconductor element and the lead are covered with a sealing resin. And the lead
Make sure that the coefficient of thermal expansion is equal to the coefficient of thermal expansion of the sealing resin
In addition, the mixing ratio of the glass fiber of the lead is adjusted.
You.

According to a fourth aspect of the present invention, the resin forming the lead according to the first, second, or third aspect is made of a thermoplastic resin. According to a fifth aspect of the present invention, in the semiconductor package, the lead and the sealing resin according to the first, second, third or fourth aspect are made of the same resin or a resin having the same thermal expansion coefficient.

According to a sixth aspect of the present invention, a semiconductor device is fixed to a resin lead frame having a conductive metal layer formed on a surface thereof. A resin lead frame is electrically connected to the electrodes of the semiconductor element. The semiconductor element and the resin lead frame are covered with a sealing resin. The resin lead frame is heated to soften the resin lead frame. The external terminals of the leads of the softened resin lead frame are cut off from the resin lead frame and molded. Then, the semiconductor element and resin lead frame
In the process of coating the frame with the sealing resin, the lead frame
The coefficient of thermal expansion of the system and the coefficient of thermal expansion of the sealing resin become equal
Use a sealing resin with an adjusted glass fiber mixing ratio.
It is characterized by having.

[0010]

[Action] The semiconductor package of this invention, leads Ri Do a resin material to form a conductive metal layer on the surface, of the lead
Make sure that the coefficient of thermal expansion is equal to the coefficient of thermal expansion of the sealing resin
In addition, the mixing ratio of the glass fiber of the lead is adjusted.
Therefore , the amount of thermal expansion of the lead and the sealing resin can be substantially equal,
The internal stress caused by the temperature change can be reduced. According to the method for manufacturing a semiconductor package of the present invention,
When the plastic mold package is separated from the lead frame and molded, and the external terminals of the lead are molded, the external terminals of the lead can be molded with relatively low stress by heating and softening the lead.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor package according to a first embodiment of the present invention is of the SOJ type as shown in FIG.
And a resin lead 3 electrically connected to the Al electrode 5 of the semiconductor element 1, and a sealing resin 2 covering the semiconductor element 1 and the resin lead 3.

Resin lead 3 and resin die pad 4
Form a conductive metal layer 8 on the surface. The conductive metal layer 8 is obtained by forming a Cu layer by plating. The tip of the internal terminal of the resin lead 3 further forms a Ni / Au layer on the Cu layer. In the semiconductor element 1, a conductive metal layer 8 of a resin die pad 4 is adhered to the back surface with an Ag paste 7. Al electrode 5 of semiconductor element 1
Are connected to the conductive metal layer 8 at the tip of the internal terminal of the resin lead 3 by the Au wire 6. Resin lead 3
Extends the external terminal 3a to the outside of the sealing resin 2.

Resin lead 3 and resin die pad 4
Is a resin material in which a high heat-resistant thermosetting resin such as epoxy or a high heat-resistant thermoplastic resin such as thermoplastic polyimide or polyetheramideimide is reinforced with glass fiber. These resin materials can be easily formed by molding, punching, etching or the like. The surface plating layer of Cu, Ni or Au on the surface of the conductive metal layer 8 can be easily formed by a technique such as photolithography or etching. It can be selectively formed. In the resin lead frame, the mixing ratio of the glass fibers is adjusted so that the coefficient of thermal expansion is equal to that of the sealing resin 2.

In manufacturing, first, the semiconductor element 1 is fixed to a resin lead frame having a conductive metal layer 3 formed on the surface, and the resin lead frame is connected to the Al electrode 5 of the semiconductor element 1 with an Au wire. Connecting. The resin lead frame and the semiconductor element 1 are covered with the sealing resin 2. In this state, the resin lead frame is connected to the Tg of the resin lead 3.
Alternatively, the resin is softened by heating to around Tm, and the external terminals of the leads of the resin lead frame are cut off from the resin lead frame and molded.

As described above, since the external terminals 3a of the resin lead 3 can be formed with relatively low stress by heating the resin lead 3 and the resin die pad 4, the sealing resin 2 and the resin lead 3 can be formed. Can be prevented from separating at the bonding interface, and the productivity can be improved. Further, since the resin lead 3 and the resin die pad 4 and the sealing resin 2 are made of resins having the same thermal expansion coefficient, even if a temperature change occurs, the thermal expansion amounts of both become substantially equal, The generation of internal stress is small. Furthermore, since the resin lead 3 and the resin die pad 4 and the sealing resin 2 have excellent adhesiveness to each other, peeling, cracking, and the like hardly occur at the bonding interface between them, and the reliability of the package is improved.

Accordingly, it is possible to make the resin leads 3, the resin die pad 4, and the sealing resin 2 relatively thinner, and to reduce the thickness and density of the entire package. Moreover, the reliability of the package with respect to the heat history can be improved. Next, a semiconductor package according to a second embodiment of the present invention will be described with reference to FIG. The resin lead 13 and the resin die pad 14 are formed from a thermoplastic resin. The conductive metal layer 18 is formed only on the surface of the resin lead 13 and is not formed on the surface of the resin die pad 14.

When mounting the semiconductor element 1 on the resin die pad 14, the back surface of the semiconductor element 1 is directly fused to the thermoplastic resin forming the resin die pad 4 by thermocompression without using Ag paste. Can be. For this reason, the step of applying the Ag paste becomes unnecessary, and the cost can be suppressed. Further, by omitting the Ag paste, the thermal stress can be easily balanced, and the reliability against the thermal stress becomes higher than in the first embodiment. Other configurations and effects are the same as those of the first embodiment.

Next, a semiconductor package according to a third embodiment of the present invention will be described with reference to FIG. The resin lead 23 is formed from a thermoplastic resin. Al electrode 25
Is arranged at the center of the semiconductor element 21. The resin lead 23 extends to near the center of the main surface of the semiconductor element 21. The conductive metal layer 28 is formed only on the surface of the resin lead 23.

The semiconductor package thus configured is
Since the main surface of the semiconductor element 21 and the thermoplastic resin forming the resin lead 23 are directly fused by thermocompression bonding, a resin die pad is not required, and A is used as in the second embodiment.
g Paste becomes unnecessary, and cost reduction and high reliability can be achieved. Furthermore, the resin leads 23 can be easily routed, and the resin leads 23 adhered to the semiconductor element 21 do not fall off. Therefore, the package size can be made relatively smaller than the chip size. Other configurations and effects are the same as those of the first embodiment.

In the second and third embodiments,
The lead and the sealing resin were made of the same resin or a resin having the same coefficient of thermal expansion.

[0021]

[Effect of the Invention] The semiconductor package of this invention, Ri Do a resin material leads to form a conductive metal layer on the surface, Li
The thermal expansion coefficient of the lead is not equal to that of the sealing resin.
The mixing ratio of lead glass fiber is adjusted
Therefore , the thermal expansion amounts of the lead and the sealing resin can be made substantially equal, and the internal stress caused by a temperature change can be reduced. Therefore, it is possible to make the lead and the sealing resin relatively thin, and to achieve a reduction in the thickness and the density of the entire package. Moreover, the reliability of the package with respect to the heat history can be improved.

According to the method of manufacturing a semiconductor package of the present invention, when the plastic mold package is separated from the lead frame and molded, and when the external terminals of the lead are molded, the lead is heated and softened, thereby making it relatively easy. The external terminals of the lead can be formed with low stress. Therefore, it is possible to prevent the lead from falling off due to peeling at the bonding interface between the lead and the sealing resin, and it is excellent in productivity.

[Brief description of the drawings]

FIG. 1 is a sectional view of a semiconductor package according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a semiconductor package according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a semiconductor package according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conventional semiconductor package.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor element 2 sealing resin 3 resin lead 4 resin die pad 5 Al electrode 8 conductive metal layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-125629 (JP, A) JP-A-2-310956 (JP, A) JP-A-3-50760 (JP, A) JP-A-5-205 102645 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 23/50 H01L 21/56 H01L 23/28

Claims (6)

(57) [Claims] 1. A semiconductor device, comprising: a lead electrically connected to an electrode of the semiconductor device; and a sealing resin covering the semiconductor device and the lead, wherein the lead has a conductive metal layer on a surface. Ri Do from the formed resin material, the Li
The thermal expansion coefficient of the lead is equal to the thermal expansion coefficient of the sealing resin.
The mixing ratio of the glass fiber of the lead is adjusted so that
Semiconductor package. 2. A back surface of a semiconductor element is fused to a surface of a die pad of a resin lead having a conductive metal layer formed on a surface other than the die pad to electrically connect an electrode of the semiconductor element and a conductive metal layer of the resin lead. And the semiconductor element and the resin lead are covered with a sealing resin.
Thermal expansion between the resin lead and the resin die pad
Number and the coefficient of thermal expansion of the sealing resin are equal.
Mixing the glass fibers of the lead and the die pad
Semiconductor package with adjusted ratio . 3. The main surface of a semiconductor element is directly fused to the back surface of an internal terminal of a resin lead having a conductive metal layer formed on the surface, and the conductive metal layer of the resin lead is attached to an electrode of the semiconductor element. Electrically connected, the semiconductor element and the lead are covered with a sealing resin, and the thermal expansion coefficient of the lead is
So that the thermal expansion coefficient of the sealing resin is equal to that of the sealing resin.
A semiconductor package in which the mixing ratio of the glass fiber of the lead is adjusted . 4. The semiconductor package according to claim 1, wherein the resin forming the leads is made of a thermoplastic resin. 5. The semiconductor package according to claim 1, wherein the lead and the sealing resin are made of the same resin or a resin having the same coefficient of thermal expansion. 6. A step of fixing a semiconductor element to a resin lead frame having a conductive metal layer formed on a surface, a step of electrically connecting the resin lead frame to electrodes of the semiconductor element, And a step of covering the resin lead frame with a sealing resin; a step of heating the resin lead frame to soften the resin lead frame; and a method of manufacturing a semiconductor package and a step of forming separately the terminal from the resin lead frame, the semiconductor element and the tree
In the process of covering the lead frame made of oil with the sealing resin
Is the thermal expansion coefficient of the lead frame and the sealing resin.
Mixing ratio of glass fiber so that thermal expansion coefficient is equal
Characterized in that the encapsulation resin is adjusted.
Manufacturing method of conductor package .