JPH09181119A - Semiconductor device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissolve connection failures between a semiconductor element and a semiconductor carrier by bumping by a method wherein a bump electrode on the semiconductor carrier and an electrode pad of the semiconductor element are composed of a low melting metal, and connected by melting with respect to metals. SOLUTION: A bump electrode 15 composed of a low melting metal is formed on an electrode 14 on the side of a semiconductor carrier 13, and by a metal connection between the bump electrode 15 and an electrode pad 12 on a semiconductor element 11, the semiconductor element 11 is connected to the semiconductor carrier 13. Further, the bump electrode 15 is formed on the electrode 14 on the side of the semiconductor carrier 13 and they are melt-connected by the electrode pad 12 on the semiconductor element 11 and pressing. Thus, it is possible to enhance reliability such as heat-resistance, wet-resistance or the like. Further, it is possible to connect by mitigating variations in a height of the bump electrode by variations of levelling of the bump electrode, and to reduce connection fail.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device which protects an integrated circuit portion of a semiconductor element, ensures stable electrical connection between an external device and the semiconductor element, and enables the highest density mounting. The present invention relates to a manufacturing method. With the semiconductor device and the manufacturing method thereof according to the present invention, it is easy to miniaturize information communication equipment, office electronic equipment, household electronic equipment, measuring equipment, industrial electronic equipment such as assembly robots, medical electronic equipment, electronic toys and the like. It is something to do.

[0002]

2. Description of the Related Art Recently, as a method for mounting a semiconductor element on a circuit board, a package using a flip chip mounting method has been studied.

A conventional semiconductor device will be described below with reference to the drawings. 7 is a plan view of a conventional semiconductor device called a chip size package (CSP), FIG. 8 is a bottom view thereof, and FIG. 9 is a sectional view taken along line AA1 of FIG.

The structure of a conventional semiconductor device will be described with reference to FIGS. 7, 8 and 9. As shown in the figure, a semiconductor element 3 having Au bumps 2 formed on an electrode pad 1 on the front surface is bonded to a semiconductor carrier 4, which is a multilayer circuit board, in a face-down manner, that is, with the front surface side facing downward. A plurality of electrodes 5 for electrical connection with the semiconductor element 3 are formed on the upper surface of the semiconductor carrier 4.
And a two-stage Au bump 2 formed on the semiconductor element 3
And are joined by a conductive adhesive 6. The gap between the bonded semiconductor element 3 and the semiconductor carrier 4 and the end of the semiconductor element 3 are filled and covered with an epoxy-based sealing resin 7. The end portion of the semiconductor element 3 and the portion covering the semiconductor carrier 4 are fillet portions of the sealing resin 7.

Here, the electrode 5 on the semiconductor carrier 4 is routed on the surface of the semiconductor carrier 4 by the wiring pattern 8 and is electrically connected to the external electrode terminal 10 on the back surface of the semiconductor carrier 4 by the via 9. The wiring pattern 8 on the surface of the semiconductor carrier 4 is routed inside the semiconductor carrier 4 which is a laminated substrate by the via 9, and the external electrode terminals 10 are arranged on the back surface of the semiconductor carrier 4 as shown in FIG. Configure.

Next, a conventional method of manufacturing a semiconductor device will be described with reference to the drawings. 10 to 13 are sectional views showing a conventional method of manufacturing a semiconductor device in the order of steps.

First, as shown in FIG. 10, Au bumps 2 (Au two-step protrusions) are formed on the electrode pads 1 of the semiconductor element 3 by a wire bonding method (ball bonding method).
To form In this method, the ball formed at the tip of the Au wire is thermally pressed against the aluminum electrode to form the lower step of the two-step protrusion (first bond), and the capillary of the wire bonder is moved to form the Au wire loop. To form the upper step portion of the two-step protrusion (second bond). In such a state, the height of the Au two-step protrusion is not uniform and lacks the flatness of the crown. Therefore, by pressing the Au two-step protrusion, the height is made uniform and the crown is flat. The so-called leveling.

Next, as shown in FIG. 11, a conductive adhesive 6 is supplied to the Au bumps 2 on the semiconductor element 3. As the conductive adhesive 6, an adhesive made of, for example, an epoxy resin as a binder and an Ag-Pd alloy as a conductor filler is used in consideration of reliability, thermal stress, and the like as described above.

Next, as shown in FIG. 12, an Au bump 2 to which the conductive adhesive 6 is supplied on the semiconductor element 3 is provided by a flip chip method, which is a method of mounting the semiconductor element 3 with its surface facing downward. Surface electrode 5 is wiring pattern 8
The surface of the semiconductor carrier 4 is routed to the front surface of the semiconductor carrier 4 by the via 9 and is internally routed by the via 9 and is electrically connected to the external electrode terminal 10 on the back surface thereof. Let it harden.

Finally, as shown in FIG. 13, epoxy-based encapsulating resin 7 is injected into the peripheral end portion of the semiconductor element 3 and a gap formed between the semiconductor element 3 and the semiconductor carrier 4 to keep the same. The semiconductor device was completed by curing the encapsulating resin and resin-molding at the temperature of.

[0011]

Conventionally, a plurality of Au bumps are formed on the electrode pads of a semiconductor element, and the bump height is leveled, and then bonded to a semiconductor carrier via a conductive adhesive. , The height of the bumps formed with the conductive adhesive on the upper step has leveling, but has a variation, and when the semiconductor element and the semiconductor carrier are joined by bumps having a height variation, ,
There was a risk of defective bonding. Further, it is very difficult to control the height accuracy of the bumps having the conductive adhesive formed on the upper part thereof. In addition, since the semiconductor element and the semiconductor carrier are bonded using a conductive adhesive, a step of forming the conductive adhesive on the bump is required. Furthermore, since the bumps are leveled by pressure on the electrode pads on the semiconductor element, there is a risk that the semiconductor element itself may be damaged by the applied pressure.

The present invention solves such a conventional inconvenience, and pays attention to the bonding of the semiconductor element and the semiconductor carrier by the bump in the flip chip mounting,
It is an object of the present invention to provide a semiconductor device in which bump height management is easy and a bonding defect between a semiconductor element and a semiconductor carrier due to the bump can be eliminated, and a manufacturing method thereof.

[0013]

In order to solve the conventional problems, a semiconductor device according to the present invention is one in which a bump electrode provided on an electrode on a semiconductor carrier is bonded to an electrode pad of a semiconductor element. The bump electrode and the electrode pad of the semiconductor element are made of a low melting point metal and are joined by melting the metals. Therefore, the semiconductor element and the semiconductor carrier are bonded together without a conductive adhesive.

Since the semiconductor element and the semiconductor carrier are bonded to each other only by the bump electrodes, the coefficient of thermal expansion differs from that of the sealing resin filling the gap between the semiconductor element and the semiconductor carrier. The conductive adhesive or the like does not exist in the gap between the carrier and the element, and reliability such as heat resistance and moisture resistance can be improved.

A method of manufacturing a semiconductor device of the present invention is a method of mounting a semiconductor element on a circuit-configured semiconductor carrier by using a flip-chip mounting method, including a step of forming bump electrodes on the semiconductor carrier side. The electrode pads on the semiconductor element are bonded to the bump electrodes on the semiconductor carrier.

In this method, a bump electrode is formed on the electrode on the semiconductor carrier side, particularly in the step of joining the semiconductor carrier and the semiconductor element, and the metal between the bump electrode and the electrode pad on the semiconductor element is changed. Since solid-phase joining is performed, the semiconductor carrier and the semiconductor element can be joined without using an adhesive means such as a conductive adhesive. Further, since the joining is performed by pressing the melted metals, it is possible to alleviate the variation in the height of the bump electrodes due to the variation in the leveling of the bump electrodes and perform the joining.
Bonding defects can be reduced.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a semiconductor device of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of this embodiment, FIG. 2 is a bottom view thereof, and FIG. 3 is a sectional view taken along the line AA1 of FIG.

As shown in FIGS. 1, 2 and 3, an electrode pad 12 on a semiconductor element 11 and an electrode 14 on a semiconductor carrier 13 which is a multilayer circuit board using ceramics as an insulating base are joined. . The bonding is performed by the bump electrode 15 made of a low melting point metal formed on the electrode 14 on the semiconductor carrier 13. In the present embodiment, the bump electrode 15 and the electrode pad 12 are
It is formed of gold (Au) as a low melting point metal,
It is solid-phase connected with gold-gold. The gap between the bonded semiconductor element 11 and the semiconductor carrier 13 and the end of the semiconductor element 11 are filled and covered with an epoxy-based sealing resin 16. Further, the end portion of the semiconductor element 11 and the portion that is in contact with the semiconductor carrier 13 are the fillet portion of the sealing resin 16, and cover the wiring pattern 17 and the via 18 on the upper surface of the semiconductor carrier 13 to prevent corrosion. Note that, in FIG. 2, the wiring pattern 17 and the via 18 covered by the fillet portion are shown by solid lines for convenience.

Although the bump electrode 15 is made of gold (Au), other than Au (gold), Pt (platinum), Ag (silver),
Al (aluminum), Sn / Zn solder or the like may be used.

In this embodiment, the encapsulating resin 7 is a high heat conductive ceramic such as aluminum nitride (AlN) or silicon carbide (S) as a filler in an epoxy resin.
iC) is added to the resin. As shown in FIG. 2, circular external electrode terminals 19 made of Ag-Pd as metallized metal layers are formed in a grid pattern at regular intervals on the bottom surface of the semiconductor carrier 4 which is a multilayer circuit board. The external electrode terminals 19 are arranged such that the electrodes 14 on the semiconductor carrier 13 are arranged inside the semiconductor carrier 13 by the wiring pattern 17 and the vias 18, and are arranged in a grid pattern on the bottom surface. The arrangement of the external electrode terminals 19 can be freely selected according to the purpose such as a zigzag arrangement other than the grid shape. In addition to Ag-Pd, Cu or Au may be used as the metallized metal layer. Further, Au plating is performed for the purpose of preventing surface oxidation of the external electrode material.

Here, the characteristic point of this embodiment is that
A bump electrode 15 made of a low melting point metal is formed on the electrode 14 on the semiconductor carrier 13 side, and the bump electrode 15 and the electrode pad 12 on the semiconductor element 11 are metal-bonded to bond the semiconductor element 11 and the semiconductor carrier 13 to each other. That is the point. Therefore, they are joined without using an adhesive means such as a conductive adhesive, and reliability such as heat resistance and moisture resistance can be improved. Further, since the bump electrode 15 is formed on the electrode 14 on the semiconductor carrier 13 side and is metal-bonded to the electrode pad 12 on the semiconductor element 11 by pressing, it is easy to manage the variation in the leveling of the bump electrode 15 and to bond it. Defects can be reduced. Further, since the bump electrode 15 is formed on the semiconductor carrier 13 side and leveled, the bump electrode 15 is not formed on the semiconductor element 11, but is applied to the semiconductor element 1 by the pressure of the leveling.
There is no loss of 1.

Regarding the reliability of the semiconductor device, in the present embodiment, the semiconductor element 11 and the semiconductor carrier 13 are joined and the gap is filled with the sealing resin 16, and the sealing resin filled in the gap. Considering the thermal expansion of 16,
It is preferable that no other material be present between the semiconductor element 11 and the semiconductor carrier 13 as much as possible. This is not preferable in terms of reliability because heat resistance, moisture resistance, etc. deteriorate when a conductive adhesive or the like having a thermal expansion coefficient different from that of the sealing resin 16 exists in the gap together with the sealing resin 16. This is because.

Next, an embodiment of a method of manufacturing a semiconductor device will be described with reference to the drawings. 4 to 6 are process drawings for explaining the present embodiment.

First, as shown in FIG. 4, a plurality of electrodes 14 on the upper surface, a wiring pattern 17 for leading the electrodes 14,
The bump electrode 15 is formed on the electrode 14 of the semiconductor carrier 13 which is arranged on the bottom surface and has the electrode 14 and the external electrode terminal 19 electrically connected by the via 18. This bump electrode 1
5 is formed by hot pressing the ball formed at the tip of the Au wire to the electrode 14 using the wire bonding method (ball bonding method) to form the lower step portion of the two-step protrusion (first bond). The upper step part of the two-step protrusion is formed by the Au wire loop formed by moving the capillary of the wire bonder (second bond).
I do. Also, in this state, the height of the Au two-step protrusion is not uniform and the flatness of the crown is also lacking.
By pressing the u two-stage protrusion, the height is made uniform and the crown is flattened, that is, so-called leveling is performed.

Next, as shown in FIG. 5, the electrode pads 12 on the semiconductor element 11 and the electrodes 14 on the semiconductor carrier 13 are formed by a flip chip method, which is a method of mounting the semiconductor element 11 with the surface thereof facing down. Align and join with good positional accuracy. In this embodiment, this bonding is performed by the electrode pad 1
2 is formed of gold (Au), and the bump electrode 15 is also formed of gold, so solid-state bonding of gold-gold is performed, and gold is melted by partial heating means such as spark and pressed to bond. In addition to the means, a semiconductor element 11 and a semiconductor carrier 1
Ultrasonic waves are applied to 3 to melt the gold (Au) of the electrode pad 12 and the gold of the bump electrode 15 and press it.

Finally, as shown in FIG. 6, epoxy-based encapsulating resin 16 is injected into the peripheral end portion of the semiconductor element 11 and a gap formed between the semiconductor element 11 and the semiconductor carrier 13 to keep a constant amount. The sealing resin is cured at a temperature and resin-molded to complete the semiconductor device.

As described above in the present embodiment, since the bump electrode 15 is formed on the electrode 14 on the semiconductor carrier 13 side and the electrode pad 12 on the semiconductor element 11 is solid-phase bonded to the metal, The semiconductor carrier 13 and the semiconductor element 11 can be joined without using an adhesive means such as a conductive adhesive. Moreover, since the joining is performed by pressing the molten metals together, the variation in the height of the bump electrode 15 due to the variation in the leveling can be alleviated and the joining can be reduced. Further, since the bump electrode 15 is formed on the semiconductor carrier 13 side and leveled, it is not formed on the semiconductor element 11 and then leveled thereon, and there is no loss of the semiconductor element 11 due to the pressure of the leveling. .

In this embodiment, the bump electrode 15
And the electrode pad 12 are made of gold, but in addition to gold, Pt (platinum), Ag (silver), Al (aluminum), C
Any material capable of solid phase bonding such as u (copper) may be used.

Next, as a reference, a method of manufacturing the semiconductor carrier 13 shown in this embodiment will be described. First, ceramic powder is put into a mixing mill together with glass powder and a solvent, and rotary mixing and pulverization are performed. Further, an organic binder is added and further mixed. This ceramic powder is usually composed mainly of alumina, but powders of aluminum nitride (AlN), silicon carbide (SiC), etc. are also added to improve the thermal conductivity. The mud obtained after thorough mixing,
The so-called slurry is applied to the conveying sheet with an arbitrary thickness for forming the green sheet. A doctor blade method or the like is used to adjust the thickness. The slurry on the carrier sheet is dried by using infrared rays and hot air to dry the solvent, thereby obtaining a green sheet having excellent elasticity and excellent permeability of the paste solvent at the time of printing the conductive paste. When the wiring rule is 200 μm or more as an alignment method for this green sheet, a guide hole is provided directly in the green sheet.
If it is less than 00 μm, it is attached to a holding frame having guide holes. Next, holes are formed by mechanical processing in the front and back portions of the green sheet where electrical conduction is required. These holes are filled with a conductive paste mainly containing Cu powder by a printing method. Next, after printing a necessary circuit on the surface of the green sheet and drying, the printed circuit is embedded in the green sheet with an appropriate load. The purpose of this is to flatten the surface of the green sheet on which the circuit is printed, thereby preventing lamination failure in the next lamination step, so-called delamination. In the laminating step, the laminated green sheets are accurately pressed by the guide holes provided in the green sheet or the guide holes of the holding frame to firmly bond the green sheets. Sn-P is formed on the grid-like electrode formed on the back surface of the ceramic carrier thus completed.
Apply b eutectic solder cream. Then, after supplying the high melting point solder balls to the applied solder cream using an alignment jig, the external electrode terminals that are solder bump bumps are formed by heating and melting using a reflow furnace or the like,
The semiconductor carrier 13 is formed.

According to the embodiment of the semiconductor device of the present invention, the semiconductor element 11 and the semiconductor carrier 13 are joined to each other by using a metal material of the bump electrode 15 on the semiconductor carrier 13 without using an adhesive means such as a conductive adhesive. This is performed by metal bonding with the metal material of the electrode pad 12 on the semiconductor element 11,
A conductive adhesive or the like having a thermal expansion coefficient different from the thermal expansion coefficient of the sealing resin 16 as in the prior art does not exist in the gap between the carrier / element, and reliability such as heat resistance and moisture resistance can be improved. it can.

In the embodiment of the method for manufacturing a semiconductor device of the present invention, the electrode 14 on the semiconductor carrier 13 side is particularly used in the step of joining the semiconductor carrier 13 and the semiconductor element 11.
The bump electrode 15 is formed on the bump electrode 15, and the bump electrode 15 and the electrode pad 12 on the semiconductor element 11 are solid-phase bonded to each other without using a bonding means such as a conductive adhesive. The semiconductor carrier 13 and the semiconductor element 11 can be joined. Further, since the joining is performed by pressing the melted metals, the variation in the height of the bump electrode 15 due to the variation in the leveling of the bump electrode 15 can be mitigated and the joining can be reduced.

[0033]

The semiconductor device according to the present invention does not use a bonding means such as a conductive adhesive to bond a semiconductor element and a semiconductor carrier, unlike the conventional case, and uses a metal material for a bump electrode on the semiconductor carrier and a semiconductor. It is performed by metal bonding with the metal material of the electrode on the element, and the conductive adhesive or the like does not exist in the gap between the carrier and the element, and reliability such as heat resistance and moisture resistance can be improved. .

Further, in the method of manufacturing a semiconductor device of the present invention, particularly in the step of joining the semiconductor carrier and the semiconductor element,
A bump electrode is formed on an electrode on the semiconductor carrier side, and the bump electrode and the electrode pad on the semiconductor element are pressed to perform solid-phase bonding between metals, and an adhesive means such as a conductive adhesive is used. The semiconductor carrier and the semiconductor element can be bonded without using them. Further, since the joining is performed by pressing the melted metals together, it is possible to alleviate the variation in the height of the bump electrode due to the variation in the leveling of the bump electrode, and it is possible to reduce the defective joining.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment of a semiconductor device of the present invention.

FIG. 2 is a bottom view of the embodiment of the semiconductor device of the present invention.

FIG. 3 is a sectional view of an embodiment of a semiconductor device of the present invention.

FIG. 4 is a process sectional view for explaining the embodiment of the method for manufacturing the semiconductor device of the present invention.

FIG. 5 is a process sectional view for explaining an embodiment of the method for manufacturing a semiconductor device of the present invention.

FIG. 6 is a process sectional view for explaining an embodiment of the method for manufacturing a semiconductor device of the present invention.

FIG. 7 is a plan view of a conventional semiconductor device.

FIG. 8 is a bottom view of a conventional semiconductor device.

FIG. 9 is a sectional view of a conventional semiconductor device.

FIG. 10 is a process cross-sectional view for explaining a conventional method for manufacturing a semiconductor device.

FIG. 11 is a process cross-sectional view for explaining a conventional method for manufacturing a semiconductor device.

FIG. 12 is a process sectional view for explaining a conventional method for manufacturing a semiconductor device.

FIG. 13 is a process sectional view for explaining the conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 1 Electrode Pad 2 Au Bump 3 Semiconductor Element 4 Semiconductor Carrier 5 Electrode 6 Conductive Adhesive 7 Sealing Resin 8 Wiring Pattern 9 Via 10 External Electrode Terminal 11 Semiconductor Element 12 Electrode Pad 13 Semiconductor Carrier 14 Electrode 15 Bump Electrode 16 Sealing Resin 17 Wiring pattern 18 Via 19 External electrode terminal

Claims (5)

[Claims] 1. A semiconductor carrier having a plurality of electrodes on an upper surface thereof, a wiring pattern for routing the electrodes, and external electrode terminals arranged on the bottom surface and electrically connected to the electrodes, and a semiconductor bonded to the upper surface of the semiconductor carrier. An element, a plurality of bump electrodes provided on an electrode on the semiconductor carrier and joining the semiconductor carrier and an electrode pad on the semiconductor element, a gap between the semiconductor element and the semiconductor carrier, and a peripheral edge of the semiconductor element A semiconductor device made of a resin filling and covering a portion. 2. A semiconductor carrier having a plurality of electrodes on an upper surface thereof, a wiring pattern for routing the electrodes, and external electrode terminals arranged on the bottom surface and electrically connected to the electrodes, and a semiconductor bonded to the upper surface of the semiconductor carrier. An element, a plurality of bump electrodes made of a low melting point metal, which are provided on the electrodes on the semiconductor carrier, and are metal-bonded to the semiconductor carrier and an electrode pad made of a low melting point metal on the semiconductor element; A semiconductor device comprising a resin filling and covering a space between the semiconductor carrier and the peripheral edge of the semiconductor element. 3. A semiconductor carrier having a bump electrode and a wiring pattern on a first surface, and the wiring pattern and an external electrode terminal electrically connected to the inside on the second surface, with respect to the bump electrode. A step of forming a bump electrode, a step of joining an electrode pad on a semiconductor element to a bump electrode on the semiconductor carrier, a sealing resin is injected into a gap between the semiconductor element and the semiconductor carrier, and the resin is cured. And a step of performing encapsulation. 4. A semiconductor carrier having a bump electrode and a wiring pattern on a first surface, and the wiring pattern and an external electrode terminal electrically connected to the inside on the second surface, with respect to the bump electrode on the semiconductor carrier. A step of forming a bump electrode made of a low melting point metal, and an electrode pad made of a low melting point metal on a semiconductor element is brought into contact with the bump electrode on the semiconductor carrier, and the bump electrode and the electrode pad are joined by melting. A method for manufacturing a semiconductor device, comprising: a step; and a step of injecting a sealing resin into a gap between the semiconductor element and the semiconductor carrier, curing the resin, and sealing the resin. 5. A low melting point metal on the bump electrode of a semiconductor carrier having a bump electrode and a wiring pattern on a first surface and the wiring pattern and an external electrode terminal electrically connected therein on a second surface. A bump electrode on the semiconductor carrier, and a step of applying pressure to the bump electrode on the semiconductor carrier, and contacting the bump electrode on the semiconductor carrier with an electrode pad made of a low melting point metal on a semiconductor element. , A step of joining the bump electrode and the electrode pad by melting, and a step of injecting a sealing resin into a gap between the semiconductor element and the semiconductor carrier and curing the resin to perform resin sealing. A method of manufacturing a semiconductor device, wherein a bump electrode is formed on the semiconductor carrier side in consideration of the influence of pressure.