JPH09172042A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the structure of a semiconductor device which has a very high adaptability to the warp of a mother board after the device is mounted on the mother board with a flexible tape used as an interconnection board whereby the mounting workability to mother board and connection reliability are improved. SOLUTION: First slits 17 are cut through a peripheral flexible tape 2 on which semiconductor elements 5 of a semiconductor device 1 are mounted and second slits are provided on diagonal lines of the tape 2, defined by the outline of the device 1. A mounting interconnection board of the elements 4 and interconnection boards 18 of external connection electrodes 7 are separated by the first slits 17 and supported with interconnection patterns 3 formed on one face of the tape 2. The boards 18 with the electrodes 7 disposed thereon are independent each other by the second slits 17 as boundaries. The pattern 3 inside the first slits is formed to provide steps between the mounting board of the elements 4 and interconnection board 18 of the electrodes 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a package structure in which a semiconductor element is mounted on a wiring board based on a flexible tape.

[0002]

2. Description of the Related Art In recent years, various consumer and industrial electronic devices have been rapidly reduced in size, weight, thickness, and performance due to remarkable progress in electronics technology. Furthermore, in consumer electronic devices, it is essential to provide cheaper products. In addition to thinning, fine patterning, and miniaturization of electronic components to be used, it is also necessary to provide cheaper electronic components. The situation is unavoidable. Various types of electronic components have been developed. Particularly, as a means for easily realizing the miniaturization and high performance of the electronic components described above, the form of a semiconductor package such as a ball grid array is used. Among them, there has been proposed a form of a semiconductor package such as a ball grid array using a flexible tape as a base of a wiring board, which can provide an inexpensive semiconductor package relatively easily. This is a technology that uses a long flexible tape, a TAB mounting technology in a reel-to-reel system, and a mounting technology called gang bonding, whereby semiconductor elements can be continuously and collectively bonded to a wiring substrate made of a flexible tape. From the viewpoint, there is an advantage that the productivity can be improved and a totally inexpensive package can be provided.

In addition, by employing TAB mounting technology on a wiring board made of a flexible tape, it is extremely easy to reduce the pitch of leads connected to the electrodes of the semiconductor element, and it is also easy to reduce the size of the semiconductor element. It becomes feasible. If the semiconductor element can be miniaturized, the number of semiconductor elements to be taken per wafer increases, so that the semiconductor element can be inexpensive, and the semiconductor device on which the semiconductor element is mounted naturally becomes inexpensive.

On the other hand, wire bonding is well known as a mounting technique using metal wires. However, since the metal wires are connected one by one, the number of electrodes of the semiconductor element is large. The more it increases, the lower the productivity. Further, there is a disadvantage that the pitch of the electrodes of the semiconductor element cannot be reduced, and it is difficult to reduce the cost of the semiconductor element. By the way, T
By adopting the AB mounting technique, it is possible to mass-produce up to 60 μm of the semiconductor element electrode pitch, whereas when adopting the wire bonding mounting technique, it is possible to mass-produce up to 90 μm of the semiconductor element electrode pitch.

By the way, gang bonding is a mounting technique in which heat and pressure are applied to a bonding tool to collectively bond electrodes of a semiconductor element and leads formed on a wiring board made of a flexible tape. A semiconductor package completed by using a flexible tape and using a mounting technique such as TAB is called a tape ball grid array. FIG. 6 is a sectional structure of a semiconductor device called a tape ball grid array. In FIG.
Reference numeral 1 is a semiconductor device called a tape ball grid array, 2 is a flexible tape, and a flexible long tape-shaped material such as polyimide or polyester is used as a base of a wiring board. A wiring pattern 3 is formed on one surface of the flexible tape 2. Reference numeral 4 is a semiconductor element, and 5 is an electrode of the semiconductor element 4. Leads 6 electrically connected to the electrodes 5 of the semiconductor element 4 are formed at one end of the wiring pattern 3 by the number of the electrodes 5 of the semiconductor element 4. The lead 6 is formed so as to overhang in the device hole 9 provided in the center of the flexible tape 2 and not to short-circuit to the edge of the semiconductor element 4 when the semiconductor element 4 is mounted. The other end of the wiring pattern 3 is connected to an external connection electrode 7 which is formed on one surface of the flexible tape 2 and is planarly arranged at a constant interval on the same surface as the wiring pattern 3. In this way, the wiring board 18 is formed.

The tips of the leads 6 are collectively joined to the electrodes 5 of the semiconductor element 4 by gang bonding. 1
Reference numeral 1 denotes a solder resist, which is protected by a solder resist 11 except at least the electrodes 7 for external connection.
Reference numeral 8 is a solder ball mounted on the external connection electrode 7, and has a role of electrically relaying the external connection electrode 7 and the connection terminal of the motherboard. Actually, the solder balls 8 mounted on the external connection electrodes 7 are soldered to the connection terminals of the motherboard by reflow.

The semiconductor element 4 is resin-sealed with a molding agent 10 in order to protect it from the external environment. The molding agent 10 is a liquid resin, and as a method for supplying the molding agent 10, a coating method using a dispenser, a printing method using a printing machine, or the like is adopted. The semiconductor device 1 called a tape ball grid array thus completed is
In addition to being inexpensive as described above, the flexibility of the flexible wiring board 2 is utilized to be extremely adaptable to physical bonding stress after the semiconductor device 1 is mounted on the mother board, and the bonding portion due to thermal fatigue It is said that high reliability can be obtained against solder ball cracks.

[0008]

A problem of a semiconductor device called a tape ball grid array described in the prior art will be described. FIG. 7 is a cross-sectional view showing the problems of the prior art. Here, detailed description of the same reference numerals as those in FIG. 6 is omitted.

Reference numeral 13 is a mother board, and the method of connecting the semiconductor device 1 to the mother board 13 is as follows.
The solder balls 8 mounted on the
Solder to the connection terminal 14 on the side. Here, if the semiconductor device 1 can be mounted on the mother board 13 without any problem, the flexibility of the flexible tape 2 is utilized,
Even if the motherboard 13 is warped, the semiconductor device 1
Has enough flexibility to follow this warp. Also,
Since the semiconductor device 1 is extremely adaptable to physical bonding stress, the semiconductor device 1 can have high reliability even with respect to solder ball cracks at the bonding portion due to thermal fatigue due to temperature cycles and the like.

However, as compared with a rigid wiring board such as a ceramics wiring board or a plastics wiring board, the flexible tape 2 is more likely to warp, which is the greatest obstacle in mounting the semiconductor device 1 on the motherboard 13. . Therefore, as a method of correcting the warp of the flexible tape 2, a frame such as 12 is fixed to the outer periphery of the flexible tape 2 by using an adhesive or the like. Thereby, the flatness of the flexible tape 2 can be ensured.

Therefore, the mountability of the semiconductor device 1 on the motherboard 13 is significantly improved by the frame 12. Frame 12
As the material of, generally, metal or hard plastic is used. However, while the mountability on the motherboard improves, the connection reliability after mounting tends to decrease. As shown in FIG. 7, when the mother board 13 warps after mounting, the frame 12 is made of metal or hard plastic, and the mechanism by which the flexible tape 2 tries to follow the warp of the mother board 13 is hindered. To be done.

Therefore, stress is applied to the joint between the solder ball 8 mounted on the external connection electrode 7 of the semiconductor device 1 and the connection terminal 14 of the motherboard 13, and FIG.
As shown in, cracks 15 may occur at the joint between the solder ball 8 and the connection terminal 14 of the motherboard 13,
For example, it often occurs when thermal stress or mechanical stress is constantly or intermittently applied to the joint. The cracks 15 also occur at the joint interface between the solder ball 8 and the connection terminal 14 of the motherboard 13 or at the solder ball 8 itself, and in the worst case, an open defect occurs at the joint. Frame 12
It is expected that if a flexible material is used as the material of the flexible tape 2, the adaptability to the warp of the motherboard is increased, the stress of the joint is relieved, and the open defect of the joint can be prevented. However, a vicious cycle occurs in which the implementability cannot be guaranteed and the implementability decreases.

Therefore, according to the present invention, after a semiconductor device called a tape ball grid array is mounted on a mother board, the semiconductor device is highly adaptable to the warp of the mother board, and the flexibility of the flexible tape can be fully utilized. As a result, it is an object of the present invention to easily provide a semiconductor device capable of improving connection reliability with a mother board.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and its contents will be described below with reference to the embodiments shown in the drawings.

According to another aspect of the semiconductor device of the present invention, the flexibility of the flexible tape used in the semiconductor device is not lost, and the semiconductor device is mounted on the mother board, and after that, the semiconductor device is more adaptable to the warp of the mother board. The first slit is provided on the flexible tape around which the semiconductor element is mounted, and the second slit is provided on a diagonal line of the flexible tape based on the outer shape of the semiconductor device.

According to a second aspect of the present invention, in addition to the features of the first aspect described above, the semiconductor element is mounted with the first slit provided around the wiring board on which the semiconductor element is mounted as a boundary. The formed wiring board and the wiring board on which the external connection electrodes are arranged are supported by at least a wiring pattern formed on one surface of the flexible tape.

According to a third aspect of the present invention, in addition to the features of the first and second aspects described above, the wiring board on which the external connection electrodes are arranged is a flexible tape based on the outer shape of the semiconductor device. Each of them is independent with a second slit provided on the diagonal line as a boundary.

According to a fourth aspect of the semiconductor device, in addition to the features of the first, second and third aspects described above, the first aspect
By forming the wiring pattern in the slit, a step is provided between the wiring board on which the semiconductor element is mounted and the wiring board on which the external connection electrodes are arranged.

[0019]

Therefore, according to the semiconductor device of the first aspect, the flexible tape is provided with the first slit and the second slit, so that after the semiconductor device is mounted on the motherboard, the warp of the motherboard is prevented. The flexibility is high, and the stress applied to the joint between the semiconductor device and the motherboard can be relieved, and the connection reliability is greatly improved.

In addition to this, according to the semiconductor device of the second aspect, the wiring board on which the semiconductor element is mounted and the wiring board on which the external connection electrodes are arranged are formed on at least one surface of the flexible tape. Since it is supported only by the wiring pattern, the adaptability to the warp of the mother board becomes higher, and the operation according to claim 1 can be easily realized.

According to another aspect of the semiconductor device of the present invention, the wiring board on which the electrodes for external connection are arranged is formed by the second slits provided on the diagonal line of the flexible tape based on the outer shape of the semiconductor device. Since they are independent of each other, the external connection electrode groups arranged on the four sides of the semiconductor device do not interfere with each other against the warp of the motherboard, so that the operation according to claim 1 can be realized more easily. Can be made.

Further, according to the semiconductor device of the fourth aspect, by forming the wiring pattern in the first slit, the wiring board on which the semiconductor element is mounted and the wiring board on which the external connection electrode is arranged are provided. A step is formed between the two, and this step can alleviate the physical stress caused by the warp of the motherboard.

[0023]

1 is a sectional view schematically showing an embodiment of the present invention. FIG. 2 is a plan view schematically showing the first embodiment of the present invention, which can be said to be the basic structure of the present invention.

In FIGS. 1 and 2, 1 is a semiconductor device, and 2 is a flexible tape such as polyimide or polyester. A wiring pattern 3 is formed on one surface of the flexible tape 2.
A lead 6 electrically connected to the electrode 5 of the semiconductor element 4 is formed at one end of the wiring pattern 3, and the lead 6 overhangs in a device hole 9 provided in the center of the flexible tape 2. ing. Further, bumps 16 connected to the electrodes 5 of the semiconductor element 4 are provided at the tips of the leads 6.

Reference numeral 7 denotes an external connection electrode, which is arranged on the same surface as the wiring pattern 3 formed on the flexible tape 2 in a plane at regular intervals. This external connection electrode 7
The shape may be any shape, and a typical shape is a round shape or a square shape, and the round shape is adopted in this embodiment. In this way, the wiring board 18 is formed. Reference numeral 8 is a solder ball mounted on the external connection electrode 7, and is soldered to the connection terminal of the mother board by reflow. Therefore,
The solder balls 8 play a role of establishing electrical connection between the semiconductor device 1 and the mother board. Reference numeral 10 denotes a molding agent, and the active surface of the semiconductor element 4 and the vicinity of the joint between the electrode 5 and the bump 16 of the semiconductor element 4 are resin-sealed by, for example, a coating method using a dispenser or a coating machine. I do.

Reference numeral 11 denotes a solder resist, at least the external connection electrode 7 is exposed, and the other parts are protected by the solder resist 11. The external connection electrode 7 needs to be exposed in order to mount the solder ball 8. Reference numeral 17 denotes a first slit, which is provided on the flexible tape 2 around which the semiconductor element 4 is mounted.
Further, 19 is a second slit, which is provided on a diagonal line of the flexible tape 2 based on the outer shape of the semiconductor device 1.

By the way, the above-mentioned semiconductor device 1 is completed through the manufacturing steps and manufacturing methods described below.
First, a hole called a device hole 9 is formed in a flexible tape 2 having flexibility such as polyimide or polyester by using a press. The size of the device hole 9 is determined by the size of the semiconductor element 4. At the same time when the device hole 9 is opened, a first slit 17 is formed around the device hole 9 and a second slit 17 is formed on a diagonal line of the flexible tape 2 based on the outer shape of the semiconductor device 1. The corner of the first slit 17 is in a state of being held by the flexible tape 2.

Next, a copper foil is laminated on the flexible tape 2 having the device hole 9 by using an adhesive. The thickness of the flexible tape 2 is wide, for example, from 25 μm to 250 μm, and the thickness is set at intervals of 25 μm, and it is selected according to the purpose and application. The width of the flexible tape 2 is, for example, 35 mm, 48 mm, 70 mm.
, Which is also selected according to the purpose and application. The thickness of the copper foil is, for example, 18 μm, 25 μm, or 35 μm, and is selected depending on the purpose and application. The width of the copper foil is determined by the width of the flexible tape 2 and the like.

Next, the copper foil is patterned by etching to form the wiring pattern 3 and the external connection electrode 7. Needless to say, before etching, the copper foil is subjected to a treatment such as exposure and development at a predetermined position so that the wiring pattern 3 and the external connection electrode 7 are formed. A lead 6 electrically connected to the electrode 5 of the semiconductor element 4 is formed at one end of the wiring pattern 3 thus formed by etching. The lead 6 overhangs in the device hole 9. Further, it is formed so as not to short-circuit with the edge of the semiconductor element 4.

Next, bumps 16 for connecting to the electrodes 5 of the semiconductor element 4 are formed at the tips of the leads 6. The bump 16 is configured to be connected to the electrode 5 of the semiconductor element 4 by providing a protrusion on the tip of the lead 6, and is short-circuited outside the range to be connected to the electrode 5 of the semiconductor element 4 and the edge of the semiconductor element 4. It is formed by half-etching the lead 6 in the range. Here, it goes without saying that all the copper foil surfaces other than the half-etched leads 6 are covered so as not to be etched.

Next, parts other than the external connection electrode 7 are protected by the solder resist 11. Since the solder balls 8 are mounted on the external connection electrodes 7, it is necessary to expose them. Thereafter, the copper foil on which the bumps 16 are formed is plated with nickel, and the nickel plating is plated with gold. At this time, the conductor surfaces other than the bumps 16 are also similarly processed.
Nickel plating and gold plating are applied. In this way, the wiring board 18 made of the flexible tape 2 is formed.

Next, the bump 16 formed at the tip of the lead 6 and the electrode 5 of the semiconductor element 4 are connected. The connection method is called gang bonding, in which heat and pressure are applied to the bonding tool to crush the bumps 16 and the semiconductor element 4 is pressed.
The electrode 5 is joined. The heat and pressure applied to the bonding tool differ depending on the thickness of the bumps 16 formed on the tips of the leads 6, the number of electrodes 5 of the semiconductor element 4, and the like, so that appropriate bonding conditions are set while performing the condition setting. Further, since the flexible wiring board 2 is formed on the long tape, the semiconductor element 4 can be mounted by the reel-to-reel method. Therefore, the semiconductor element 4 is continuously mounted on the wiring board 18, so-called T
Since the AB mounting method is possible, the productivity is improved, and as a result, the inexpensive semiconductor device 1 can be easily provided. Here, in the present embodiment, the bump 16 connected to the electrode 5 of the semiconductor element 4 is provided at the tip of the lead 6 formed at one end of the wiring pattern 3 formed on the flexible tape 2, but the electrode of the semiconductor element 4 is provided. 5 may be provided with bumps.

Next, the active surface of the semiconductor element 4 mounted on the wiring board 18 and the electrodes 5 and the bumps 16 of the semiconductor element 4 are mounted.
In order to protect the vicinity of the joint portion with and from the external environment, resin molding is performed with the molding agent 10. The vicinity of the joint portion here means not only the joint portion between the electrode 5 of the semiconductor element 4 and the bump 16, but also at least the cross section of the semiconductor element 4 and
The area in which the leads 6 overhang in the device hole 9 is referred to. A liquid resin is adopted as the mold resin 10, and the mold resin 10 is supplied by a coating method using a dispenser or a coating method using a printing machine.

Next, solder balls 8 are placed on the external connection electrodes 7.
Melt and fix. Even when the solder balls 8 are melted and fixed, they are joined by reflow as in the case of mounting the semiconductor device 1 on the mother board. The reflow temperature at this time is as described above.

Finally, the semiconductor device 1 formed on the long flexible tape 2 is cut into individual pieces using a press to complete the semiconductor device 1.

Although various arrangement methods can be considered for the first slit 17 and the second slit 19, the second embodiment of the present invention will be described with reference to FIG. 2 as a basic structure and FIGS. Examples, third embodiment and fourth embodiment will be described. Here, detailed description of the same reference numerals as those in FIG. 2 is omitted. FIG. 3 is a plan view schematically showing a second embodiment of the present invention, and FIG. 4 is a third view of the present invention.
It is the top view which showed the example typically. FIG. 5 is a sectional view schematically showing a fourth embodiment of the present invention.

The feature of the second embodiment is that, as shown in FIG. 3, the corners of the first slits 17 formed around the device hole 9 are not held by the flexible tape 2, and the wiring on which the semiconductor element 4 is mounted is mounted. Substrate 18 and external connection electrode 7
The wiring board 18 on which is arranged is only held by the wiring pattern 3. The first slit 17 in this case is
If the device hole 9 is opened at the same time as punching out, the device hole 9 becomes hollow and cannot be formed. Therefore, when the semiconductor device 1 is finally cut into individual pieces, the flexible tape 2 left at the corner of the first slit 17 may be cut. In this way, since the wiring board 18 on which the semiconductor element 4 is mounted and the wiring board 18 on which the external connection electrodes 7 are arranged are only held by the wiring pattern 3, it is more adaptable to the warp of the motherboard. Get higher

Next, as shown in FIG. 4, the characteristic feature of the third embodiment is that it is provided around the device hole 9 and the second slit 19 provided on the diagonal of the flexible tape 2 based on the outer shape of the semiconductor device 1. This is that the formed first slit 17 is integrated. Similar to the second embodiment, they are integrated at the same time when the semiconductor device 1 is cut into individual pieces. As a result, the wiring board 18 on which the semiconductor element 4 is mounted and the wiring board 18 on which the external connection electrodes 7 are arranged are held only by the wiring pattern 3.
Since the slit 17 and the second slit 19 are integrated, the external connection electrodes 7 arranged on the four sides of the semiconductor device 1 are completely independent. For this reason,
Since the wiring boards 18 on which the external connection electrodes 7 are arranged do not interfere with each other against the warp of the motherboard, the adaptability to the warp of the motherboard is further enhanced.

Next, the feature of the fourth embodiment is that the wiring pattern 3 in the first slit 17 is formed as shown in FIG. By forming, the wiring board 18 on which the semiconductor element 4 is mounted and the wiring board 18 on which the external connection electrode 7 is arranged are in different steps, and the formed wiring pattern 3 in this portion plays a role of stress relaxation. become. This can be realized by providing the first slit 17. Forming is performed using the forming type. Further, a step between the wiring board 18 on which the semiconductor element 4 is mounted and the wiring board 18 on which the external connection electrodes 7 are arranged, that is, a forming amount is preferably at least 25 μm or more. 25 μm is the thinnest thickness of the flexible tape 2, and the stress can be relieved if there is a step of at least this thickness. Also, the first
When forming the wiring pattern to protect the wiring pattern exposed in the slit from the external environment and then overcoating the resist to protect the wiring pattern or coating a coating agent such as epoxy resin into the first slit There is also. By doing so, the wiring pattern is never damaged or cut due to external stress or the like.

In the semiconductor device called a tape ball grid array according to the present invention, after mounting the semiconductor device on a mother board, a semiconductor device having higher adaptability to the warp of the mother board can be easily realized and the connection reliability is sufficient. It is possible to easily provide a semiconductor device that can be secured.

[0041]

As is apparent from the above description, in the present invention, a semiconductor device called a tape ball grid array is provided with a first slit in a flexible tape around which a semiconductor element is mounted, and the external shape of the semiconductor device is further improved. A wiring board in which a second slit is provided on a diagonal line of a flexible tape used as a reference, and a wiring pattern in the first slit is formed, and a wiring board on which a semiconductor element is mounted and electrodes for external connection are arranged. By providing a step between and, the following effects can be obtained.

(1) Since the adaptability of the semiconductor device to the warp of the mother board is extremely high, the connection reliability is extremely improved.

(2) The physical stress due to the warp of the mother board is relieved at the forming portion, and the connection reliability is further improved.

(3) From the above, it is possible to easily provide a semiconductor device capable of significantly improving the connection reliability between the semiconductor device and the motherboard.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing an embodiment of the present invention.

FIG. 2 is a plan view schematically showing a first embodiment according to the present invention.

FIG. 3 is a plan view schematically showing a second embodiment according to the present invention.

FIG. 4 is a plan view schematically showing a third embodiment according to the present invention.

FIG. 5 is a sectional view schematically showing a fourth embodiment according to the present invention.

FIG. 6 is a cross-sectional view of a semiconductor device called a tape ball grid array.

FIG. 7 is a cross-sectional view showing the problems of the conventional technique.

[Explanation of symbols]

 1 Semiconductor Device 2 Flexible Tape 3 Wiring Pattern 4 Semiconductor Element 5 Electrode 6 Lead 7 External Connection Electrode 8 Solder Ball 9 Device Hole 10 Molding Agent 11 Solder Resist 12 Frame 13 Motherboard 14 Connection Terminal 15 Crack 16 Bump 17 First Slit 18 Wiring board 19 Second slit

Claims (4)

[Claims] 1. A flexible tape is a base of a wiring board, a wiring pattern is formed on one surface of the flexible tape, and external connection electrodes are formed on the same surface on which the wiring pattern is formed. Are located,
A semiconductor device in which one end of the wiring pattern is connected to an electrode of a semiconductor element and the other end is connected to the external connection electrode, and at least the active surface side of the semiconductor element and the vicinity of the semiconductor element are resin-sealed. The semiconductor device according to claim 1, wherein the flexible tape around the semiconductor element is provided with a first slit, and a second slit is provided on a diagonal line of the semiconductor device. 2. The semiconductor device according to claim 1, wherein
At least a wiring board on which the semiconductor element is mounted and a wiring board on which the external connection electrode is arranged are separated by a first slit provided on the flexible tape around the semiconductor element mounted. A semiconductor device supported by the wiring pattern. 3. The semiconductor device according to claim 1, wherein
The wiring board on which the electrodes for external connection are arranged is independent of each other with a second slit provided on a diagonal line of the semiconductor device as a boundary. 4. The semiconductor device according to claim 1, wherein
By forming a wiring pattern in the first slit, a step is provided between the wiring board on which the semiconductor element is mounted and the wiring board on which the external connection electrode is arranged. .