JP3480285B2 - Semiconductor device and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

Ultrasonic bonding method between the present invention is a semi-conductor device and to a manufacturing method of that <br/>, semiconductor chip bonding pad and the lead frame bonding portion of which is especially mounted in position BACKGROUND OF THE INVENTION Form to join with
Regarding semiconductors device and a manufacturing method thereof.

[0002]

2. Description of the Related Art A semiconductor chip is incorporated into a package and commercialized. As the assembly process at this time,
First, a lead frame is prepared in which a die pad portion on which a semiconductor chip is mounted and a portion to be an external lead are formed by cutting and bending. Next, the semiconductor chip is mounted on the die pad portion of the lead frame, and the semiconductor chip and The lead frame is electrically connected by wire bonding, etc., the semiconductor chip is sealed with resin, the lead frame is solder-plated, and the other parts of the lead frame are left and the other parts are cut off. Bend the lead into a specified shape, stamp it, perform an operation test,
Finally, the resin-sealed portion is separated from the tie bar portion of the lead frame to form a package.

Although an example in which the resin-sealed portion is finally cut off is shown here, the portion to be the lead of the lead frame after being sealed with the resin is left and the other portions are cut off at the same time. Sometimes.

FIG. 9 is a partial plan view showing an example of a conventional lead frame. In the illustrated example, the lead frame 1 has a tape shape, and four die pad portions 2a, 2b, 2c, for mounting semiconductor chips in the lateral direction thereof.
2d is provided. Although not shown, 20 die pad portions 2 are also provided in the vertical direction of the lead frame 1, respectively, so that a total of 80 semiconductor elements in 4 columns and 20 rows can be manufactured by one lead frame. .

According to the lead frame 1, for example, the die pad portion 2a is connected in the lateral direction (vertical direction in the figure) to its peripheral portion by the tie bar portions 3a and 3b, and the die pad portion 2a is formed during the assembly process. Is working to hold. On the other hand, looking at the longitudinal direction of the die pad portion 2a, in this example, four lead portions 4a, 4b, 4c, 4d to be leads are formed on the right side thereof, and these four lead portions 4a, 4b, 4c and 4d are coupled to each other by a tie bar portion 5, and further, bonding portions 6a and 6b for performing wire bonding with a semiconductor chip mounted on the die pad portion 2a are formed. Further, on the left side of the die pad portion 2a, four lead portions 8a, 8b, 8c, 8d that are continuous with the die pad portion 2a and are coupled to each other by the tie bar portion 7 are formed. As a semiconductor chip, one MOS type FET
(Field effect transistor) is mounted on the die pad portion 2a. Therefore, from this lead frame 1, an SOP (Small Out-line P) having four leads on each side.
An ackage type MOS type FET device will be manufactured.

In this type of semiconductor element, a semiconductor chip must be mounted on the die pad portion 2a within a limited size, soldered there, wire bonded, and resin-sealed. If the leads are to be led out from the middle position of the package thickness, the semiconductor chip needs to bond wires from the bonding pads on the top surface, so make sure that there is sufficient space on the upper side for resin sealing. I can't. Therefore, the die pad portion 2a on which the semiconductor chip is mounted is pushed down by the press working and is lowered.

FIG. 10 is a partial plan view showing an example of a conventional lead frame on which a semiconductor chip is mounted. In this figure, each die pad portion 2a, 2 of the lead frame 1
The semiconductor chips 9 of the MOS type FET are provided at b, 2c and 2d.
a, 9b, 9c and 9d are mounted respectively, and their back surfaces are soldered to the die pad portions 2a, 2b, 2c and 2d. The back surfaces of the semiconductor chips 9a, 9b, 9c and 9d form the drain electrodes of the MOS type FETs. Therefore, for example, the semiconductor chip 9a has the die pad portion 2
By being soldered to a, the four lead parts 8
a, 8b, 8c and 8d serve as common drain terminals. The upper surface of the semiconductor chip 9a has a bonding pad 10a forming a source electrode and a bonding pad 10b forming a gate electrode. The bonding pad 10a is connected to the bonding portion 6a by an aluminum wire 11, for example, and the bonding pad 10b is formed. Is connected to the bonding portion 6b. Therefore, the three lead portions 4a, 4b, 4c serve as a common source terminal of the MOS type FET, and the lead portion 4d serves as a gate terminal.

The wire bonding is performed by ultrasonic bonding. In ultrasonic bonding, ultrasonic energy is applied to the wire 11 to bond the wire 11 to the bonding pads 10a and 10b and the bonding portions 6a and 6b.
Join to b. At this time, the lead frame 1 is clamped so as not to move by a clamp device (not shown). Further, from the upper surface, the lead portion is pressed by a comb-shaped pressing member to fix the periphery of the die pad portion and from the lower surface. Is the die pad portions 2a, 2b, 2c, 2
The back surface of d is sucked downward by a vacuum device (not shown), and the die pad itself is adsorbed and fixed.

[0009]

In the lead frame 1, after the unnecessary portion is punched from the tape-shaped metal plate, the die pad portions 2a, 2b, 2c, 2d semiconductor chip mounting surface is pushed down by press working. At this time, the die pad portions 2a, 2b, 2c and 2d have lead portions 8 on three sides.
a, 8b, 8c, 8d and the tie bar portions 3a, 3b, but they are not held evenly from all sides, so bending of the portion holding the die pad portions 2a, 2b, 2c, 2d Is not performed accurately, and an error occurs in bending, resulting in die pad portions 2a, 2b, 2c, 2d.
May become slanted. Further, at the time of bonding, the die pad portions 2a, 2b, 2c, 2d are fixed by suction from the back surface thereof. But,
The die pad portions 2a, 2b, 2c, 2d are connected to the lead portion 8a,
8b, 8c, 8d and the tie bar portions 3a, 3b are not sufficiently held, and suction is performed on a portion having a small area, so that sufficient suction and fixing cannot be performed. Therefore, the die pad portions 2a, 2b, which are not sufficiently fixed,
Since ultrasonic bonding is performed on the semiconductor chips mounted on 2c and 2d, the bonding pads 10a and 10b resonate during wire bonding, and ultrasonic vibration energy is dispersed without being concentrated on the wires. As a result, there is a problem in that wire bonding failure occurs.

[0010] The present invention has been made in view of these points, even if the wire bonding such as ultrasonic bonding, so as not failure occurred in the wire bonding to bonding pads on the semiconductor chip semi conductor arrangement
And a method for manufacturing the same.

[0011]

According to SUMMARY OF THE INVENTION The present invention, a die pad section for mounting a semiconductor chip Te semiconductor device odor <br/> using a lead frame that is held by the tie bar portions, the said die pad tie bar Department holds
The edges of the sides, and the die pad portion <br/> example is that the die pad pressing area the die pad portion is pressed by the pressing member
Provided integrally , and the tie bar portion is linearly arranged.
The die pads are arranged in a zigzag pattern between the die pad portions.
There is provided a semiconductor device characterized in that the cord portions are connected to each other .

According to the above structure, when the aluminum wire is wire-bonded by ultrasonic bonding, the pressing member presses the die pad pressing area, so that the die pad portion on which the semiconductor chip is mounted is fixed from the outer peripheral edge portion, and the semiconductor chip is fixed. The ultrasonic vibration energy in the bonding pad of the above is not dispersed. Therefore, the wire bonding at the bonding pad of the semiconductor chip does not cause a bonding failure.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described as an example in which it is applied to a lead frame in the case of manufacturing an element having two semiconductor chips mounted thereon.

FIG. 1 is an enlarged plan view of an essential part of the lead frame of the present invention. The illustrated lead frame 20 shows only a portion corresponding to one package, and two die pad portions 21 and 22 are formed for mounting two independent semiconductor chips. These die pad parts 2
1, 22 are held by the tie bar portions 23, 24 from the lateral direction, and the die pad portions 21, 2 are held from the top in the figure.
The lead portion 2 which constitutes a lead having the same potential as the lead portion 2.
It is held by 5, 26, 27 and 28. Tie bar portions 23, 24 and lead portions 25, 26, 27, 28
The connecting portion of is formed obliquely when the die pad portions 21 and 22 are pressed down below the main surface of the lead frame 20 by press working. Also, the die pad 2
1, 22 are die pad pressing areas 29, 3 from the upper edge of the figure to the vicinity of the tie bars 23, 24 along the outer peripheral edge.
Has 0. Further, below the die pad portions 21 and 22 in the drawing, a lead portion that constitutes a lead electrically insulated from the die pad portions 21 and 22 and the bonding portions 31, 32, 33 and 34 that are one end thereof. Are formed.

Further, in FIG. 1, a portion indicated by a chain double-dashed line shows a mold outline of the resin portion when the semiconductor chip mounted on the die pad portions 21 and 22 is sealed with resin. The tie bar portions 23 and 24, which hold the die pad portions 21 and 22 from the lateral direction, have brittle portions 35 and 36 at positions inside the mold outer shape, that is, the two-dot chain line. The brittle portions 35 and 36 are formed by cutting the lead portion,
After forming, when the package is finally cut from the lead frame 20, the cut portion is located inside the end surface of the package.

FIG. 2 is a plan view showing the lead frame at the time of bonding. On the die pad portions 21 and 22 of the lead frame 20, semiconductor chips 37 and 38 of, for example, MOS type FETs are mounted, and the back surfaces forming the drain electrodes of these are electrically connected to the die pad portions 21 and 22, respectively. The semiconductor chips 37 and 38 have bonding pads 39 and 40 on their upper surfaces which form gate electrodes.
And the bonding pads 41 and 4 which constitute the source electrode
2 and. The bonding pads 39 and 40 are connected to the bonding portions 32 and 34 by aluminum wires 43 and 44, and the bonding pads 41 and 42 are connected.
Is bonded to the bonding portions 31, 33 by the wires 45, 46.
Connected to.

At the time of this wire bonding, the lead frame 20 is pressed from above by the pressing member. That is, the lead parts 25, 2 at the portions rising from the die pad parts 21, 22 to the main surface of the lead frame 20.
6, 27 and 28 are pressed from the upper surface by the pressing members 47 and 48, and the lead portions connected to the bonding portions 31 to 34 on the opposite side are pressed from the upper surface by the pressing members 49, 50, 51 and 52. Further, in the present invention, the die pad pressing areas 29 and 30 provided on the peripheral portions of the die pad portions 21 and 22 are pressed by the pressing members 53 and 54 from the upper surface.

As described above, the die pad portions 21 and 22 are pushed through the die pad holding areas 29 and 30 by the holding member 5.
Since the die pads 21 and 22 are sufficiently fixed by being pressed by 3, 54, even if the semiconductor chips 37, 38 receive ultrasonic vibration energy during ultrasonic wire bonding, the vibration energy Can be concentrated on the wire to be bonded without being dispersed, and compared with the case where the lead frame 20 is held only by the holding members 47, 48, 49, 50, 51, 52, by the holding members 53, 54. The joint failure can be reduced from 25.5% to almost 0% by using the die pad holding areas 29 and 30 together.

FIG. 3 is a sectional view taken along the line AA of FIG. As shown in the figure, during wire bonding with ultrasonic waves,
The lead frame 20 is pressed from above by the pressing members 48 and 52, and the die pad portion 22 is sufficiently fixed by the pressing member 54 pressing the die pad pressing area 30 from above. Further, a suction nozzle 55 is arranged below the die pad portion 22. A vacuum device (not shown) is connected to the suction nozzle 55 so as to suck the die pad portion 22 from the back surface. In this way, the wire 44 is bonded to the semiconductor chip 38 and the bonding portion 34 by ultrasonic bonding while the lead frame 20 is fixed.

FIG. 4 is a sectional view taken along the line BB of FIG. As shown in the figure, the tie bar portion 23 rising from the die pad portion 21 has a brittle portion 35 on the same surface as the main surface of the lead frame 20. Here, the two-dot chain line shows the mold outer shape when the semiconductor chip is resin-sealed by transfer molding, and the brittle portion 35 is provided at a position inside the mold outer shape. The brittle portion 35 is formed of a U groove in the illustrated example, but may be formed of a V groove or a cutout portion. This brittle part 3
Reference numeral 5 denotes a portion that makes it easy to finally cut off the resin-sealed package from the lead frame 20. When cutting off, the brittle portion 35 tears the package.

Next, another example of the layout of the die pad pressing area in the lead frame for mounting two semiconductor chips will be described. FIG. 5 is an enlarged plan view of an essential part of a lead frame according to the second embodiment of the present invention. 5, elements corresponding to those shown in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.
In the illustrated example, in addition to the die pad portions 21 and 22 having die pad holding areas 29 and 30, respectively, the die pad portion 21 has an outer peripheral edge portion from the vicinity of the tie bar portion 23 to the lower edge portion of the figure. A die pad pressing area 61 integrally provided along the center and a die pad pressing area 62 provided at the center of the lower edge portion of the drawing are provided. For the die pad portion 22, a die pad pressing area integrally provided at the center of the lower edge portion of the drawing is provided. It has an area 63. By providing the die pad pressing areas 62 and 63, the bonding portions 31 and 33 arranged so as to face each other are formed in a shape that does not come into contact with the die pad pressing areas 62 and 63, respectively.

FIG. 6 is a plan view showing the lead frame at the time of bonding. As shown in FIG. 6, at the time of wire bonding, first, the lead portions of the die pad portions 21 and 22 rising from the upper edge portion in the figure to the main surface of the lead frame 60 are pressed by the comb-shaped pressing member 65. The lead portions of the die pad portions 21 and 22 arranged to face the lower edges of the figures are held by the comb-teeth-shaped holding member 66. Further, the die pad pressing areas 29, 6 provided on the outer peripheral portions of the die pad portions 21, 22 in the figure.
1, 62, 63, 30 are pressed by pressing members 67, 68. Here, the holding members 67 and 68 for holding the die pad holding area are arranged on the lower side, and the holding members 65 and 66 for holding the lead portion are arranged on the upper side thereof so as not to interfere with the bonding. As well shown in this figure, the die pad portions are arranged in the lateral direction, but the tie bar portions 23 and 24 holding each other are not located in the central portion of each die pad portion, It is provided at a position alternately shifted upward or downward in the drawing from the central portion. The staggered arrangement of the tie bars will be described later.

As described above, the die pad portions 21 and 22 are provided with die pad holding areas 29 and 6 on their outer peripheral portions.
By being pressed by the pressing members 65 to 68 through 1, 62, 63 and 30, the defective bonding rate of the wires during wire bonding can be brought closer to 0%.

Next, an example of the layout of the die pad holding area in the lead frame for mounting one semiconductor chip will be described. FIG. 7 is an enlarged plan view of an essential part of a lead frame according to the third embodiment of the present invention. The illustrated lead frame 70 has only one die pad portion 71 for mounting one MOS type FET chip, for example. This die pad portion 71 shows one of four pieces arranged in the lateral direction, and the respective die pad portions are connected to each other in the lateral direction by tie bar portions 72 and 73. Then, on the outer peripheral portion of the die pad portion 71,
Die pad holding areas 74, 75, 76, 77 are provided. These die pad holding areas 74, 7
5, 76 and 77 are die pad portions 71 excluding the tie bar portions 72 and 73 at the edge portions where the tie bar portions 72 and 73 are present.
It is provided on the outer peripheral portion of the above, and is provided so as to be located in the empty space in accordance with the shapes of the bonding portions 78 and 79 located at the lower edge portion in the figure.

The die pad portion 71 during wire bonding
By pressing these die pad pressing areas 74, 75, 76, 77 provided on the outer peripheral portion of the wire, the die pad portion 71 on which the chip is mounted is sufficiently fixed, and the vibration energy of ultrasonic waves is not dispersed. It will be possible to perform reliable bonding by concentrating on.

Next, a case where the chip is resin-sealed after the wire bonding is completed will be described. 8A and 8B are views showing a mold for resin sealing, FIG. 8A is a view of the mold seen from above, and FIG. 8B is a sectional view taken along the line C-C.
As shown in the figure, the mold for resin sealing is composed of an upper mold 81 and a lower mold 82, each of which is provided with a concave portion so that a cavity 84 is formed at a position corresponding to each die pad portion of the lead frame 83, A resin flow portion 85 communicates between the cavities 84. This resin flow part 85
Are provided alternately, that is, in a staggered manner, so as to avoid the tie bar portions connecting the die pad portions of the lead frame 83. A runner 86 for supplying resin is connected to the leading gate of each row of the die pad portion of the lead frame 83. The resin is, for example, an epoxy resin containing spherical silica, silicone, a silane coupling agent and the like.

At the time of resin sealing, first the runner 86 is used.
The resin flows into the cavity to fill the first cavity. After that, the further inflowing resin flows into the second cavity through the resin flow portion 85. At this time, since the resin flow portion 85 communicating with the second cavity is provided at a position diagonal to the gate into which the resin flows, the resin that has flowed in flows in the first cavity in a direction perpendicular to the flow direction of the runner 86. Instead of flowing straight, the flow crosses diagonally. As a result, the resin is spread to every corner of the cavity. Since the resin flow portions 85 connecting the cavities are arranged in a zigzag manner, the reliable resin filling state in the first cavity similarly occurs in the second and subsequent cavities, and as a result, all the cavities are filled. The resin is surely filled with.

Although the present invention has been described above with reference to its preferred embodiments, the present invention is not limited to these embodiments. For example, the present invention is not limited to ultrasonic bonding, but can be applied to a lead frame for a semiconductor chip on which other wire bonding such as thermocompression bonding is performed.

[0029]

As described above, in the present invention, the die pad holding area is provided at the outer peripheral edge of the chip mounting area of the die pad portion on which the semiconductor chip is mounted. As a result, the pressing member can press the die pad pressing area directly to fix the die pad portion sufficiently, and when vibration energy is applied like ultrasonic bonding, the energy is consumed by resonance of the die pad portion. Instead of being concentrated on the wires, the wires can be reliably bonded to the semiconductor chip, and the bonding failure can be reduced to almost 0%.

Since the tie bar portion holding the die pad portion is provided with the brittle portion at a position inside the outer shape of the mold, the tie bar portion is surely cut at the brittle portion. As a result, the tie bar portion after cutting is not exposed from the resin portion, so that there is no problem of contact with other components when the semiconductor element is mounted on the substrate.

Furthermore, the zigzag arrangement of the tie bars for connecting the die pad parts to each other allows the die pad part to be accommodated in the die for resin-sealing the die pad part on which the chip is mounted and wire bonding is performed. The resin flow portions between the cavities can be staggered. As a result, the flow of the resin at the time of resin sealing is improved and the resin is surely distributed in each cavity, so that the incidence of defective packages can be reduced.

[Brief description of drawings]

FIG. 1 is an enlarged plan view of a main part of a lead frame of the present invention.

FIG. 2 is a plan view showing a lead frame at the time of bonding.

FIG. 3 is a sectional view taken along the line AA of FIG.

FIG. 4 is a sectional view taken along the line BB of FIG.

FIG. 5 is an enlarged plan view of a main part of a lead frame according to a second embodiment of the present invention.

FIG. 6 is a plan view showing a lead frame at the time of bonding.

FIG. 7 is an enlarged plan view of an essential part of a lead frame according to a third embodiment of the present invention.

FIG. 8 is a view showing a mold for resin encapsulation, (A)
Is a view of the mold seen from above, and (B) is a cross-sectional view taken along the line CC.

FIG. 9 is a partial plan view showing an example of a conventional lead frame.

FIG. 10 is a partial plan view showing an example of a conventional lead frame on which a semiconductor chip is mounted.

[Explanation of symbols]

20 lead frame 21,22 Die pad part 23,24 Tie bar section 25,26,27,28 Lead part 29,30 die pad holding area 31, 32, 33, 34 Bonding part 35,36 Brittle part

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-349883 (JP, A) JP-A-3-276747 (JP, A) JP-A-4-211138 (JP, A) Actual Kaihei 5- 87965 (JP, U) Actual development Sho-49-133560 (JP, U) Actual development 2-91356 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 23 / 48-23 / 50,21 / 60

Claims (9)

(57) [Claims] 1. A lead frame in which a die pad portion for mounting a semiconductor chip is held by a tie bar portion is used.
In the semiconductor device described above, a die pad holding area where the die pad portion is held by a holding member is integrated with the die pad portion at an edge portion of the side of the die pad portion held by the tie bar portion.
And the tie bar portion is arranged in a straight line
The die pad parts are arranged in a zigzag pattern between the die pad parts.
A semiconductor device characterized in that the semiconductor devices are connected to each other . 2. The tie bar portion of the die pad portion is retained.
At the edge of the side next to the side you have, the die pad
The gap between the bonding parts of the lead parts that are spaced around
The die pad portion is projected by the pace and is pressed by the pressing member.
Another die pad holding area that can be held is
The unit according to claim 1, characterized in that it is provided integrally with the pad section.
Semiconductor device. 3. The same semiconductor chip is mounted on each
Two die pads to be molded in the package
The die pads are arranged in a straight line and each die pad
Using the lead frame held by the bar
In the semiconductor device, the two die pad portions arranged adjacent to each other are
The tie bar part on the side opposite to the side facing the
Edge of the same side held by the tie bar part
The die pad part is pressed by the pressing member on the part.
That the die pad holding area is integrated
Characteristic semiconductor device. 4. The tie bar portion is linearly arranged.
The die pads are arranged in a staggered pattern.
The semiconductor device according to claim 3, 5. The die pad portion is the tie bar portion.
At the edge of the side next to the held side, the die pad
Between the bonding parts of the lead parts that are spaced apart around the parts
Projecting into the space of
There is a separate die pad holding area where the
4. The half according to claim 3, which is provided on the body.
Conductor device. 6. The tie bars arranged in a staggered pattern
The semiconductor switch of mounting the die pad portion of the multiple coupled to each other
Of semiconductor devices for wire bonding
In the manufacturing method, the side of the die pad portion held by the tie bar portion is
Press the die pad holding area that is integrally provided on the edge
Wire bonding is performed by pressing even the member
A method of manufacturing a semiconductor device, comprising: 7. A side adjacent to a side held by the tie bar portion
The space between the bonding parts of the lead parts that are spaced apart on the
Provided integrally with the die pad so as to project at a pace.
Separated die pad holding area on the holding member
Characterized by performing wire bonding while holding down more
The method for manufacturing a semiconductor device according to claim 6. 8. The position of adjacent die pads facing each other
The same die pad holding area
Wire bonding is performed while pressing with the pressing member.
7. A method of manufacturing a semiconductor device according to claim 6, wherein
Law. 9. The staggered arrangement between the die pad portions.
Staggered resin flow avoiding the tie bars
The sealing resin is supplied from the section.
Or a method of manufacturing a semiconductor device according to 7.