JP2000124251A - Semiconductor device, manufacture thereof, circuit board and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which can be formed readily and has bumps suitably bondable to leads, a manufacturing method thereof, a circuit board and electronic equipment. SOLUTION: This manufacturing method comprises a first step 1 of bonding a lead 16 to one of a plurality of electrodes 12 of a semiconductor element 10, a step 2 of cutting off the bonded lead 16, while leaving a part thereof on the electrode 12, a step 3 of pressing a part of the left lead 16 on the electrode 12 to form a bump 24 having flat top end face, and a step 4 of bonding a lead having a width smaller than the top end face width of the bump 24 to the bump 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device and a method of manufacturing the same, a circuit board, and an electronic device.

[0002]

BACKGROUND OF THE INVENTION There is known a method of forming a bump on an electrode of a semiconductor device by using a wire bonding technique.
For example, Japanese Patent Application Laid-Open No. 57-163919 describes a method in which a wire is bonded to an electrode using a capillary, and the wire is torn off to leave a residue of the wire on the electrode and use it as a bump. According to this method, bumps can be formed faster than stacking plating.

[0003] However, the bump formed by tearing off the wire does not have a sufficient flat upper end surface, so there is no problem when the semiconductor element is face-down bonded to the substrate, but when the lead is bonded to the bump. There was a problem that joining accuracy was inferior. That is, even if the upper end surface of the bump is mountain-shaped or has a small area even if there is a flat region, the bonding area with the lead is insufficient, and the lead may slip off the bump. .

The present invention solves this problem, and an object of the present invention is to provide a semiconductor device having a bump which can be easily formed and which can be appropriately bonded to a lead, a method of manufacturing the same, a circuit board, and an electronic device. To provide equipment.

[0005]

(1) A method of manufacturing a semiconductor device according to the present invention includes a first step of bonding a conductive line to any one of a plurality of electrodes of a semiconductor element; A second step of cutting while leaving a part of the conductive wire on the electrode, and a third step of pressing a part of the conductive wire left on the electrode to form a bump having a flat upper end surface; Bonding a lead having a width smaller than the width of the upper end surface of the bump to the bump using a tool.

According to the present invention, a bump can be formed only by bonding a conductive wire to an electrode, cutting a part of the electrode wire while leaving the electrode, and pressing the same to flatten the upper end surface. This step can be performed in a shorter time than the step of forming a bump by plating. Further, in the present invention, since the upper end surface of the bump is flattened by pressing, and the width of the lead is smaller than the width of the upper end surface of the bump, a good bonding is secured even if the position of the lead is slightly shifted. You.

(2) In this method of manufacturing a semiconductor device, before the third step, the first step and the second step are repeated, and a part of the conductive line is provided on each of a plurality of electrodes. In the three steps, a part of the conductive lines left on the plurality of electrodes may be simultaneously pressed to form a plurality of bumps at the same time.

According to this, since a plurality of bumps can be formed simultaneously, the process can be further shortened.

(3) In this method of manufacturing a semiconductor device, the lead is formed so as to protrude inside an opening formed in the substrate, and in the fourth step, the bump is arranged in the opening. The leads may be bonded to the bumps in the openings.

(4) A semiconductor device according to the present invention comprises: a semiconductor element having a plurality of electrodes; a lower portion provided on each electrode and in contact with the electrode; and an upper portion having a smaller width than the lower portion. The semiconductor device includes a bump, a lead bonded to the bump and having a width smaller than an upper end surface of the upper portion of the bump, a substrate on which the lead is formed, and an external electrode electrically connected to the lead.

According to the present invention, the lead is bonded to the upper end surface of the upper portion having a smaller width than the lower portion of the bump, but since the width of the lead is smaller than the upper end surface of the bump,
Good bonding is ensured even if the positions of the leads are slightly shifted.

(5) In this method of manufacturing a semiconductor device, an opening is formed in the substrate, the lead is formed so as to protrude inside the opening formed in the substrate, and the bump and the lead are formed. May be bonded in the opening.

(6) The semiconductor device is mounted on a circuit board according to the present invention.

(7) An electronic device according to the present invention has the circuit board described above.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a semiconductor device to which a BGA package is applied is manufactured by applying the present invention.

FIGS. 1A and 2B are views showing a process of forming a bump on an electrode of a semiconductor element. First, as shown in FIG. 1A, a semiconductor element (semiconductor chip) 10 on which one or a plurality of electrodes 12 are formed is prepared. Each electrode 12 is made of, for example, aluminum
Are often formed thin and flat on the surface on which the active element is formed. However, the shape of the side surface or the longitudinal section is not particularly limited as long as the shape of the bump is not formed, and the surface is flush with the surface of the semiconductor element 10. You may. Also, the planar shape of the electrode 12 is not particularly limited, and may be circular or rectangular.

The electrode 1 in such a semiconductor device 10
The capillary 14 is arranged on the side of the surface on which 2 is formed.
A conductive wire 16 such as a wire is inserted through the capillary 14. The conductive line 16 is often made of gold, copper, aluminum, or the like, but is not particularly limited as long as it is a conductive material. The conductive wire 16 has a ball 17 formed outside the capillary 14. The ball 17 is formed at the tip of the conductive wire 16 by performing high-voltage discharge using, for example, an electric torch.

Then, the capillary 14 is arranged above any one of the electrodes 12, and the ball 17 is arranged above any one of the electrodes 12. The clamper 18 is opened, the capillary 14 is lowered, and the ball 1 is
Press 7. Ultrasonic waves, heat, and the like are applied while the ball 17 is pressed against the electrode 12 by pressing the ball 17 at a constant pressure. Thus, the conductive line 16 is bonded to the electrode 12 as shown in FIG.

Then, the clamper 18 is closed and the conductive wire 16 is closed.
Is held, and the capillary 14 and the clamper 18 are simultaneously raised as shown in FIG. Thus, the conductive line 16 is torn off, and a portion including the ball 17 remains on the electrode 12. If there are a plurality of electrodes 12 for which bumps need to be formed, the above steps are repeated for the plurality of electrodes 12.

A part of the conductive wire 16 (including the ball 17) remaining on the electrode 12 is convex on the crimped ball 17, but its upper end surface is small and flat. Often not.

Therefore, the steps shown in FIGS. 2A and 2B are performed. That is, as shown in FIG. 2A, the semiconductor element 10 in which a part (including the ball 17) of the conductive wire 16 bonded on the electrode 12 is left is placed on the table 20, and As shown in B), a part of the conductive wire 16 (including the ball 17) is crushed by the pressing jig 22. In the present embodiment, a part of the conductive wire 16 remaining on the plurality of electrodes 12 is crushed at the same time, but a part of the conductive wire 16 (including the ball 17) may be crushed for each electrode 12. good.

In this manner, bumps 24 are formed on the respective electrodes 12 as shown in FIG. Bump 2
4 comprises an upper part 26 and a lower part 28. The lower portion 28 is a portion formed by crushing the ball 17 and is joined to the electrode 12 with a larger area than the upper portion 26. The upper portion 26 is a portion formed by crushing a part of the cut conductive line 16 and is smaller than the lower portion 28 in a plan view. Further, the upper end surface of the upper portion 26 is flattened by being crushed by the pressing jig 22.

Next, as shown in FIGS. 3A and 3B, the leads 32 are bonded to the bumps 24. That is, as shown in FIG. 3A, the semiconductor element 10 is placed on the table 40, the leads 32 formed on the substrate 30 are disposed above the semiconductor element 10, and the pressing jig 42 is disposed thereon. In addition, as the table 40 and the pressing jig 42, the table 20 and the pressing jig 22 used when crushing a part of the conductive wire 16 remaining on the electrode 12 may be used.

The substrate 30 may be formed of either an organic or inorganic material, or may have a composite structure of these. As the substrate 30 formed of an organic material, for example, a flexible substrate made of a polyimide resin is used. As the flexible substrate, a tape used in TAB technology may be used. In addition, as the substrate 30 formed of an inorganic material, for example, a ceramic substrate or a glass substrate can be used.
As a composite structure of an organic material and an inorganic material, for example, a glass epoxy substrate can be given.

A wiring pattern 34 is formed on the substrate 30. The wiring pattern 34 is formed on one surface of the substrate 30. An opening (device hole) 36 is formed in the substrate 30, and one or a plurality of leads 32 protrude inside the opening 36. The lead 32 is
It is electrically connected to the wiring pattern 34.

As shown in FIG. 3A, such a substrate 30 is arranged with the leads 32 and the wiring pattern 34 facing the opposite side to the semiconductor element 10. Also, the substrate 30
Are arranged such that the bumps 24 of the semiconductor element 10 are located inside the openings 36. Further, each lead 32 formed on the substrate 30 is located on any of the bumps 24.

Then, as shown in FIG. 3B, the lead 32 is bonded to the bump 24 by a pressing jig 42. Specifically, the lead 32 is bent by the pressing jig 42 and pressed against the bump 24, and the two are joined by applying ultrasonic vibration, heat, or the like. When joined, the materials forming the leads 32 and the bumps 24 are melted by vibration or heat. Here, when gold is used for the bump 24 and the surface of the lead 32 made of copper is coated with tin, a eutectic of gold-tin is formed. Further, in the present embodiment, gang bonding for bonding a plurality of leads 32 simultaneously is performed, but single point bonding may be performed.

When a substrate having a structure in which the lead does not project into the opening is used, the lead is pressed to the bump through the substrate.

In the present embodiment, since the lead 32 is located on the side opposite to the semiconductor element 10, the lead 32 is bent inside the opening 36. Alternatively, when the lead 32 is arranged on the side of the semiconductor element 10 for bonding, the lead 32 may not be bent.

The lead 32 is, as shown in FIG.
The bonding is performed with the tip protruding from the bump 24. By doing so, even if there is an error in the position between the lead 32 and the bump 24, at least the upper part 2 of the bump 24
Since the lead 32 crosses the upper end surface of the lead 6, a large bonding area between the lead 32 and the bump 24 can be ensured.

Further, as shown in FIG.
2 and a width W2 of the upper end surface of the upper portion 26 of the bump 24.
Is in a relation of W1 <W2, and particularly preferably in a relation of W1 ≦ 0.9W2.

By designing in this way, even if there is an error in the position of the lead 32 with respect to the bump 24,
From the upper end surface of the upper part 26 of the lead 32.

Through the above steps, the leads 32 of the semiconductor element 10 can be bonded.

According to the present embodiment, the bumps 24 are formed by bonding the conductive wires 16 to the electrodes 12 and cutting them while leaving a part of the conductive wires 16 on the electrodes 12, and pressing the flattened upper surface. can do. This step can be performed in a shorter time than the step of forming a bump by plating. Further, since the upper end surface of the bump 24 is flattened by the pressing, and the width of the lead 32 is smaller than the width of the upper end surface of the bump 24, good bonding is secured even if the position of the lead 24 is slightly shifted. You.

Next, the semiconductor device shown in FIG. 5 is obtained by the conventional steps. The semiconductor device shown in FIG. 5 uses a BGA package. That is, the semiconductor device shown in FIG.
0 and the wiring pattern 34
External electrodes 50 provided on the semiconductor element 10
And the surface mounting is enabled by the external electrode 50.

The external electrodes 50 are, for example, solder balls, and the leads 32 electrically connected to the wiring pattern 34.
Is electrically connected to the electrode 12 of the semiconductor element 10 via the. The external electrode 50 may be formed of, for example, copper or the like other than solder. A solder resist 52 is applied to the surface of the substrate 30 where the wiring pattern 34 is formed, avoiding the external electrodes 50. Solder resist 52
Is designed to cover and protect the surface of the wiring pattern 34 in particular.

When a flexible substrate is used as the substrate 30, a plate-shaped stiffener 54 is provided on the side opposite to the external electrodes 50. The stiffener 28 is formed of copper, stainless steel, a copper-based alloy, or the like, has a strength capable of maintaining a planar shape, and is attached to the substrate 30 via an insulating adhesive 56. Note that the insulating adhesive 56 is formed as a thermosetting or thermoplastic film. Further, the stiffener 54 is attached to the entire substrate 30, avoiding the semiconductor element 10. By doing so, the substrate 3
Zero distortion and undulation are eliminated, the height of the external electrode 50 becomes constant, the planar stability is improved, and the mounting yield on the circuit board is improved.

Further, the electrode 12 of the semiconductor element 10
A heat radiating plate 60 is adhered to the surface opposite to the surface on which is formed via a heat conductive adhesive 58 such as a silver paste.
Thereby, the heat dissipation of the semiconductor element 10 can be improved. The heat radiating plate 60 is formed larger than the semiconductor element 10 and is also adhered on the stiffener 54. Note that the space between the stiffener 54 and the heat radiating plate 60 is also bonded with a heat conductive adhesive 58 to be airtight.
The heat conductive adhesive 58 may be replaced with a normal insulating adhesive or the above-mentioned insulating film depending on the amount of heat generated by the semiconductor element 10.

The space between the semiconductor element 10 and the substrate 30 is sealed with a potted epoxy resin 62. The epoxy resin 62 also goes around the opening 36 and the outer periphery of the semiconductor element 10.

FIG. 6 shows a semiconductor device 1 to which the present invention is applied.
The circuit board 1000 on which the circuit board 100 is mounted is shown. Generally, an organic substrate such as a glass epoxy substrate is used for the circuit board. Wiring patterns made of, for example, copper are formed on the circuit board so as to form a desired circuit, and the electrical continuity is achieved by mechanically connecting the wiring patterns and external electrodes of the semiconductor device.

FIG. 7 shows a notebook personal computer 1200 as an electronic apparatus having the circuit board 1000.

By applying the present invention, electronic devices (whether active or passive) as well as semiconductor devices
Bumps can be formed on the electrodes. Electronic components manufactured from such electronic elements include, for example, resistors, capacitors, coils, oscillators, filters, temperature sensors, thermistors, varistors, volumes, or fuses.

[0043]

[Brief description of the drawings]

FIGS. 1A to 1C are diagrams illustrating a conductive wire bonding step according to an embodiment of the present invention.

FIGS. 2A and 2B are diagrams illustrating a method for forming a bump according to an embodiment of the present invention.

FIGS. 3A and 3B are diagrams showing a lead bonding step in the embodiment of the present invention.

FIGS. 4A and 4B are diagrams showing a relationship between a lead and a bump in the embodiment of the present invention.

FIG. 5 is a diagram showing a semiconductor device according to an embodiment of the present invention.

FIG. 6 is a diagram showing a circuit board according to the embodiment of the present invention.

FIG. 7 is a diagram illustrating an electronic apparatus including a circuit board on which a semiconductor device manufactured by applying the method according to the present invention is mounted;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Semiconductor element 12 Electrode 16 Conductive line 24 Bump 26 Upper part 28 Lower part 30 Substrate 32 Lead 34 Wiring pattern 36 Opening

Claims (7)

[Claims] A first step of bonding a conductive line to any one of a plurality of electrodes of a semiconductor device; a second step of cutting the bonded conductive line while leaving a part of the conductive line on the electrode; A third step of pressing a part of the conductive wire left on the electrode to form a bump having a flat upper end face, and using a tool to form a lead having a width smaller than the width of the upper end face of the bump. A fourth step of bonding to the bumps. 2. The method of manufacturing a semiconductor device according to claim 1, wherein before the third step, the first step and the second step are repeated to provide a part of the conductive line on each of a plurality of electrodes. In the third step, a method of manufacturing a semiconductor device in which a plurality of bumps are simultaneously formed by simultaneously pressing a part of the conductive lines left on a plurality of electrodes. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the lead is formed to protrude inside an opening formed in the substrate, and in the fourth step, the bump is formed by A method of manufacturing a semiconductor device, wherein the semiconductor device is arranged in an opening and bonds the lead to the bump in the opening. 4. A bump, comprising: a semiconductor element having a plurality of electrodes; a lower portion provided on each electrode and in contact with the electrode; an upper portion having a width smaller than the lower portion; A semiconductor device comprising: a lead having a width smaller than an upper end surface of the upper portion of the bump; a substrate on which the lead is formed; and an external electrode electrically connected to the lead. 5. The semiconductor device according to claim 4, wherein an opening is formed in the substrate, the lead is formed to protrude inside the opening formed in the substrate, and the bump and the lead are formed. Is a semiconductor device bonded in the opening. 6. A circuit board on which the semiconductor device according to claim 4 is mounted. 7. An electronic apparatus having the circuit board according to claim 6.