JP2002076054A - Packaging structure of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging structure of a semiconductor device which can ensure a high reliability, when the semiconductor device is connected to a circuit board with an adhesive. SOLUTION: In the packaging structure of the semiconductor device, a bumps 13 provided on the semiconductor device 1 is electrically connected with a wiring lead 21 formed on the surface of the circuit board 2, and adhesive 3 is filled between the semiconductor device 1 and the circuit board 2. A reinforcing member 24 is provided on the rear side of a wiring lead 21 in the area including at least a position where a bump 13 is connected with the wiring lead 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a system for connecting a semiconductor integrated circuit device to a circuit board.

[0002]

2. Description of the Related Art As semiconductor devices become more highly integrated, there is an increasing demand for mounting them on a circuit board to make them smaller, thinner and more reliable. As a connection method responding to this, there is an FCA (Flip Chip Attach) connection using an anisotropic conductive adhesive, which is disclosed in JP-A-60-180132. As a result, a simple and efficient semiconductor mounting method has been established without impairing miniaturization, thinning, and high reliability. However, in the above-described conventional technique, when the semiconductor device 1 is mounted on the circuit board 2 as shown in FIG. 7, a pressing load (indicated by an arrow) from the upper surface of the IC chip 11 is required. When this load is applied to the wiring lead 21 via the bump 13 and the wiring is deformed, the bump 13
A gap is generated between the wiring lead 21 and the wiring lead 21, and the contact area is reduced. For this reason, a phenomenon occurs in which the connection resistance increases, leading to poor conduction. Therefore, as a method for solving the above problem, a semiconductor device disclosed in Japanese Patent Application Laid-Open No. 9-92683 has been proposed. This prevents the wiring leads from being deformed by attaching a reinforcing plate to the bottom surface of the circuit board and suppressing deformation of the entire circuit board. Thereby, when connecting to a circuit board using an anisotropic conductive adhesive, high reliability can be secured.

[0003]

According to the above prior art,
By preventing the deformation of the wiring lead, stable connection reliability can be realized. However, since the reinforcing plate is attached to the bottom surface of the circuit board, the thickness and weight of the board both increase. When the above technology is applied to small and lightweight devices such as mobile phones,
This can be a factor in increasing the thickness and weight of the entire device. Also,
Since the reinforcing plate is attached to the circuit board using an adhesive, the larger the area of the reinforcing plate, the greater the thermal strain generated between the reinforcing plate and the circuit board. When the adhesive strength of the adhesive decreases due to moisture absorption, the adhesion between the reinforcing plate and the circuit board cannot be maintained. If the elasticity of the resin layer is low or if there is a wiring layer in the inner layer of the substrate, the deformation of the wiring leads 21 is absorbed inside the substrate as shown in FIG. In some cases, the deformation of the wiring lead 21 cannot be sufficiently prevented.

An object of the present invention is to provide a semiconductor device mounting structure that can ensure high reliability when the semiconductor device is connected to a circuit board using an adhesive.

[0005]

According to the first aspect of the present invention, an electrode provided on a semiconductor device is electrically connected to a wiring lead formed on a surface of a circuit board. In a mounting structure of a semiconductor device in which an adhesive is filled between a semiconductor device and a circuit board, a reinforcing member is disposed on a rear side of the wiring lead, at least in a range including a portion where the electrode and the wiring lead are in contact with each other. Things.

According to a second aspect of the present invention, in the mounting structure of the semiconductor device according to the first aspect, the elastic modulus of the reinforcing member is larger than the elastic modulus of the resin layer surrounding the reinforcing member. Things.

According to a third aspect of the present invention, in the semiconductor device mounting structure according to the first or second aspect, the thermal expansion coefficient of the reinforcing member is made smaller than the thermal expansion coefficient of the resin layer surrounding the reinforcing member. It is characterized by the following.

The above-described means works as follows. According to the first aspect of the present invention, the reinforcing member is provided in an area where the electrode of the semiconductor device and the wiring lead of the circuit board are in contact with each other. There is little deformation in the wiring leads. This keeps the contact area between the bump and the wiring lead,
Electrical connection between the semiconductor device and the wiring can be performed reliably and with high reliability.

According to the second aspect of the present invention, the elastic modulus of the reinforcing member is made larger than the elastic modulus of the resin layer surrounding the reinforcing member. Deformation is further reduced, and highly reliable electrical connection can be reliably performed.

According to the third aspect of the invention, the coefficient of thermal expansion of the reinforcing member is smaller than the coefficient of thermal expansion of the resin layer surrounding the reinforcing member. When the adhesive is filled and connected between the semiconductor device and the circuit board, if the temperature is lowered after the curing of the adhesive is completed, the amount of heat shrinkage of the reinforcing member is smaller than that of the resin layer. A compressive stress is generated between the wiring lead in contact with the electrode and the electrode of the semiconductor device. Therefore, in addition to the effects of the first and second aspects, the contact area between the wiring lead and the electrode of the semiconductor device can be further increased, and the electrical connection between the semiconductor device and the circuit board can be made more reliable and highly reliable. Can be done.

Further, according to the present invention, the electrodes provided on the semiconductor device are electrically connected to the wiring leads formed on the surface of the circuit board, and an adhesive is provided between the semiconductor device and the circuit board. In the mounting structure of the filled semiconductor device,
On the front side of the wiring lead, a conductive reinforcing member is disposed in a range including at least a portion where the electrode and the wiring lead are in contact with each other.

According to a fifth aspect of the present invention, in the semiconductor device mounting structure according to the fourth aspect, the elastic modulus of the reinforcing member is equal to or larger than the elastic modulus of the wiring lead. is there.

The above-described means works as follows. According to the fourth aspect of the present invention, since the conductive reinforcing member is provided on the surface of the wiring lead, the electrode of the semiconductor device comes into contact with the conductive reinforcing member. Since the surface of the reinforcing member is less likely to be deformed than the wiring lead, the contact area between the bump and the reinforcing member is maintained, so that the electrical connection between the semiconductor device and the wiring can be performed reliably and with high reliability. .

According to the fifth aspect of the present invention, the elastic modulus of the reinforcing member is equal to or greater than the elastic modulus of the wiring lead. Deformation is further reduced, and highly reliable electrical connection can be reliably performed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the mounting structure of a semiconductor device according to the present invention will be described below with reference to FIGS. FIG. 1 is an essential view of a mounting structure of a semiconductor device according to a first embodiment of the present invention. Semiconductor device 1 of the present embodiment
On the lower surface of the IC chip 11, a predetermined electronic circuit (not shown) is formed. An electrode pad 12 is formed at a position where electrical conduction with the circuit board 2 is obtained. A bump 13 formed by gold wire bumping is arranged on the electrode pad 12.

The material of the bumps 13 is not limited to gold, but may be any material that can provide electrical conduction, such as solder, nickel, copper, aluminum, silver, or a conductive resin. The method for forming the bump is not limited, and printing, ball transfer, plating, a stud bump method, or the like may be used.

The circuit board 2 includes wiring leads 21 formed by processing a copper foil, a resin layer 22, an inner wiring 23, and a reinforcing member 24 which is a main part of the present embodiment.

The wiring leads 21 are formed so as to be disposed immediately below the bumps 13 with the IC chip 11 mounted on the circuit board 2. The wiring lead 21 made of copper foil
Is plated with nickel and gold to reduce the contact resistance with the gold bumps. Further, a solder film may be formed on the surface of the wiring lead 21 in order to perform metal bonding with the bump.

The reinforcing member 24 is formed on the back side of the wiring lead 21 and is disposed in a range including at least a portion where the bump 13 contacts the wiring lead 21. Reinforcing member 2
The material of No. 4 may be any material having a higher elastic modulus or a lower coefficient of thermal expansion than the resin layer 22 surrounding the reinforcing member 24. For example, using a method of embedding a conductive resin containing conductive particles of silver or copper or a plating method of copper,
The reinforcing member 24 may be formed at the same time when the interlayer connection through hole of the circuit board 2 is provided.

The adhesive 3 is made of, for example, an epoxy-based thermosetting resin or a silicone-based thermoplastic resin. The adhesive force between the semiconductor device 1 and the circuit board 2 can be maintained by the contraction force of the resin. At the same time, the bump 13 and the wiring lead 21
And play a role in protecting the joint. The member constituting the adhesive 3 is not limited to the above resin, but may be a member capable of bonding, such as a thermoplastic film, a thermosetting film, an anisotropic conductive paste or an anisotropic conductive film containing conductive particles. I just need.

Next, a process of connecting the semiconductor device 1 to the circuit board 2 using the adhesive 3 in the mounting structure of the semiconductor device according to the present embodiment will be described with reference to FIGS. In order to connect the semiconductor device 1 to the circuit board 2,
First, the adhesive 3 is applied on the circuit board 2. This adhesive 3
May be applied using a syringe-shaped dispenser, or a screen printing method may be used.
Further, a film-like adhesive 3 may be attached to the surface of the circuit board 2.

After the adhesive 3 is applied by the above-described method, the IC chip 11 is arranged at the chip mounting position on the circuit board 2 as shown in FIG. Next, as shown in FIG.
When a load is applied from above the bump 13 and the wiring lead 2
The adhesive 3 is removed to the periphery, and the bumps 13 and the wiring leads 21 are brought into close contact with each other to obtain electrical continuity. Here, in the mounting structure of the semiconductor device in this embodiment, the bump 1
The reinforcing member 2 is provided immediately below the wiring lead 21 at a position where the reinforcing member
4, there is little deformation of the wiring lead even if a load is applied to the wiring lead via the bump. Conventionally, the contact area between the bump and the wiring lead was reduced due to the deformation of the wiring lead, resulting in poor conduction of the connection portion. However, the present invention maintains the contact area, and the electrical connection between the semiconductor device and the circuit board is maintained. Electrical conduction can be reliably performed.

In the above mounting structure, when the elastic modulus of the reinforcing member 24 is larger than the elastic modulus of the resin layer 22 surrounding the reinforcing member, the deformation of the wiring lead 21 is further reduced in addition to the above-described operation, and higher reliability is achieved. Electrical connection can be reliably performed. Further, the coefficient of thermal expansion of the reinforcing member 24 is
When the temperature is lower than the coefficient of thermal expansion of the resin layer 22 surrounding the reinforcing member, the temperature is lowered after the curing of the adhesive 3 is completed.
Since the reinforcing member 24 has a smaller heat shrinkage than the resin layer 22, a compressive stress is generated between the wiring lead 21 and the bump 13 in contact with the reinforcing member 24. Therefore, in addition to the above operation, the contact area between the wiring lead 21 and the bump 13 further increases, and more reliable electrical connection can be reliably performed.

Next, a second embodiment of the present invention will be described with reference to FIG. Here, the same components as those in the first embodiment shown in FIG. In this embodiment, a mounting structure is shown in a case where the wiring leads 21 are used for signal transmission and are desired to be electrically independent from the inner layer wiring 23. When forming the inner layer wiring 23 located immediately below the reinforcing member 24, an opening is previously provided in the wiring by a method such as etching or laser processing. Next, the reinforcing member 24 is formed so as not to be in contact with the inner wiring 23. Thereby, the reinforcing member 24 and the inner layer wiring 23 can be electrically independent, and the wiring lead 21 in contact with the reinforcing member 24 is used for signal transmission, and the inner layer wiring 23 is used.
Can be used as a power supply and a ground layer.

Next, a third embodiment of the present invention will be described. FIG. 5 shows a cross section of a main part of a semiconductor device and a circuit board according to a third embodiment of the present invention.

The mounting structure of the semiconductor device according to this embodiment is as follows.
The first embodiment is characterized in that the bumps 13 and the wiring leads 21 are joined by soldering. In this embodiment, the solder 25 is previously formed on the wiring lead 21 in a region where the bump 13 contacts. Next, the adhesive 3 is placed on the circuit board 2.
Is applied, the IC chip 11 is arranged at the chip mounting position of the circuit board 2, and a load is applied from above the IC chip 11.
After the bumps 13 and the solder 25 come into close contact with each other due to the removal of the adhesive 3 around, the solder is melted to form the IC chip 11.
Is connected to the circuit board 2. Here, when the coefficient of thermal expansion of the reinforcing member 24 is smaller than the coefficient of thermal expansion of the resin layer 22 surrounding the reinforcing member, when the temperature is lowered after the curing of the adhesive 3 is completed, the reinforcing member 24 The amount of heat shrinkage is smaller than that of the wiring lead 21 in contact with the reinforcing member 24.
A compressive stress is generated between the bump and the bump 13. Therefore, a force is applied to the solder 25 to push it up from below. As the compressive stress increases, the horizontal shear stress generated in the solder portion is alleviated, and the connection reliability is improved. In this embodiment, the IC chip 11 is connected to the circuit board 2.
When mounting on the bumps 13, the solder 25 is first melted and
Then, the adhesive 3 is applied to the IC chip 11 and the circuit board 2.
The same effect can be achieved by filling the gap. In this case, in addition to the above-described effects, there is obtained an advantage that self-alignment is possible because of the solder connection, and that there is no need to apply a load, so that the wiring is not deformed.

The above effect is not limited to the case where the material of the bump 13 is gold, but may be solder, nickel,
This is also achieved when using a material that can provide electrical conduction, such as copper, aluminum, silver, or a conductive resin.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, the wiring leads 21 of the circuit board 2 are used.
Is a structure in which a conductive reinforcing member 24 is formed on the surface.
To mount the IC chip 11 on the circuit board 2, first, the adhesive 3 is applied to the surface of the circuit board 2, and the IC chip 11 is arranged at a chip mounting position on the circuit board 2. Then IC chip 11
By applying a load from above, the adhesive 3 between the bump 13 and the reinforcing member 24 is removed to the periphery, and the bump 13
The electrical connection is obtained by the close contact of the reinforcing member 24 with the reinforcing member 24. Here, since the load applied to the bump 13 is supported by the reinforcing member 24, the deformation of the reinforcing member 24 is reduced as compared with the conventional wiring deformation, the contact area between the reinforcing member 24 and the bump 13 is increased, and a more reliable An electrical connection can be made. Here, the material of the bump 13 is not limited to gold as in the first embodiment, but may be any material that can provide electrical conduction, such as solder, nickel, copper, aluminum, silver, or a conductive resin. .

In the above mounting structure, when the elastic modulus of the reinforcing member 24 is equal to or greater than the elastic modulus of the wiring lead, the deformation of the wiring lead 21 is further reduced in addition to the above-described operation, and a more reliable electric Connection can be reliably performed.

In the first to fourth embodiments of the present invention, an example is shown in which bumps 13 are formed on an IC chip 11 as the semiconductor device 1. However, the present invention is not limited to this. Absent. The semiconductor device 1 is also applicable to a BGA (ball grid array) on which bump electrodes are formed, a CSP (chip size package), and the like.

[0031]

As described above, according to the present invention, the deformation of the wiring leads can be prevented without attaching a reinforcing plate to the bottom surface of the circuit board. Thus, the electrical connection between the semiconductor device and the wiring can be reliably and reliably performed without increasing the thickness and weight of the substrate of a small and lightweight device such as a mobile phone. Further, since it is not necessary to use an adhesive on the bottom surface of the circuit board, reliability during moisture absorption can be ensured. Further, even when the elastic modulus of the resin layer is low or the wiring layer is provided in the inner layer of the substrate, the deformation of the wiring lead can be sufficiently prevented. Furthermore, the contact area between the bump and the wiring lead is more stable than before even if thermal strain is applied due to external force such as bending or impact, or thermal shock. An excellent information processing device can be realized.

[Brief description of the drawings]

FIG. 1 is a main view of a mounting structure of a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a view showing an assembling process of the semiconductor device mounting structure according to the first embodiment of the present invention, showing a state before the semiconductor device is pressurized.

FIG. 3 is a view showing an assembling process of the semiconductor device mounting structure according to the first embodiment of the present invention, showing a state after the semiconductor device is pressurized.

FIG. 4 is an essential view of a mounting structure of a semiconductor device according to a second embodiment of the present invention.

FIG. 5 is an essential diagram of a semiconductor device mounting structure according to a third embodiment of the present invention;

FIG. 6 is an essential view of a mounting structure of a semiconductor device according to a fourth embodiment of the present invention.

FIG. 7 is an essential diagram of an IC chip and a substrate showing an example of a conventional semiconductor device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 11 ... IC chip, 12 ... Electrode pad,
13: Bump, 2: Circuit board, 21: Wiring lead, 22
... resin layer, 23 ... inner wiring, 24 ... reinforcing member, 25 ... solder, 3 ... adhesive.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoko Yoda 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Hitachi, Ltd. Production Technology Research Laboratory (72) Inventor Takehiko Hasebe 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside Hitachi, Ltd., Production Technology Research Laboratories (72) Inventor Toyoki Asada 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi, Ltd. Production Technology Research Laboratories (72) Inventor Toshihiro Yaya 1410 Inada, Hitachinaka City, Ibaraki Prefecture Address Digital Media Product Division, Hitachi, Ltd. (72) Yoshikatsu Ishida, Inventor 1410 Inada, Hitachinaka City, Ibaraki Prefecture Digital Media Product Division, Hitachi, Ltd. (72) Inventor Morio Muramatsu, Inada, Hitachinaka City, Ibaraki Prefecture 1410 Digital Media Hitachi, Ltd. Product Division F term (reference) 5F044 KK11 KK19 LL11 5F061 AA01 BA03 CA05

Claims (5)

[Claims] An electrode provided on a semiconductor device is electrically connected to a wiring lead formed on a surface of a circuit board,
In a mounting structure of a semiconductor device in which an adhesive is filled between a semiconductor device and a circuit board, a reinforcing member is disposed on a rear side of the wiring lead, at least in a range including a portion where the electrode and the wiring lead are in contact with each other. Semiconductor device mounting structure. 2. The semiconductor device mounting structure according to claim 1, wherein an elastic modulus of the reinforcing member is larger than an elastic modulus of a resin layer surrounding the reinforcing member. 3. The mounting structure of a semiconductor device according to claim 1, wherein a coefficient of thermal expansion of the reinforcing member is smaller than a coefficient of thermal expansion of a resin layer surrounding the reinforcing member. 4. An electrode provided on the semiconductor device is electrically connected to a wiring lead formed on a surface of the circuit board.
In the mounting structure of the semiconductor device in which the adhesive is filled between the semiconductor device and the circuit board, a conductive reinforcing member is arranged on a front side of the wiring lead, at least in a range including a portion where the electrode and the wiring lead are in contact with each other. Characteristic semiconductor device mounting structure. 5. The mounting structure of a semiconductor device according to claim 4, wherein the elastic modulus of the reinforcing member is equal to or larger than the elastic modulus of the wiring lead.