JPH05114627A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a semiconductor device which can prevent generation of cracks or peelings at the connecting terminals due to a stress resulting from difference of thermal expansion coefficient while avoiding limitation on a substrate concerning thermal expansion coefficient. CONSTITUTION:A soft stress absorbing member 41 is inter posed between a substrate 21 and a pellet 11, and a connecting terminal 34 of the pellet 11 and a connecting terminal 45 of the substrate 21 are respectively formed in both sides of a wire 43 implanted on the stress absorbing member 41. Thereby, difference of deformations of the bustrate 21 and pellet 11 during change of thermal condition based on the difference of thermal expansion coefficients of the material of substrate 21 and the material of the pellet 11 can be absorbed by elastic deformation of the soft stress absorbing member 41. Therefore, stresses working on the connecting terminals 34, 45 can be controlled or restricted due to difference of deformation. As a result, generation of peeling or crack at the connecting terminals 34, 45 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, particularly a semiconductor pellet (hereinafter referred to as pellet or chip).
Relates to a semiconductor device bonded to an insulating substrate (hereinafter, simply referred to as a substrate) by a flip chip method. For example, a pellet on which an integrated circuit is formed is controlled collapse reflow bonding (hereinafter, CCB) on the substrate. That is, the technology effectively applied to a semiconductor device that is mechanically and electrically connected to each other.

[0002]

2. Description of the Related Art The flip chip method is a name given by so-called face-down bonding, in which a chip is turned upside down and bonding is performed using connection terminals formed on the surface or substrate. The flip chip method includes a ball method in which a metal ball is attached to a chip, a bump method in which a protruding electrode is formed of aluminum or a silver alloy, or a pedestal method in which a pedestal is attached to a substrate, depending on the form of the connection terminal to be formed.

The ball-type flip-chip structure is characterized in that a considerably thick low-melting glass is used as a chip protective film and that bumps for electrode connection (protruding electrodes, Bum) are used.
p) is formed from a solder (Pb-Sn) which covers the surface of a Cu ball plated with Ni and Au. In the manufacturing method, first, the surface of a conventional planar element having an Al electrode is covered with protective glass. Next, the glass film of the electrode portion is removed, an electrode base is formed of a multi-layer metal of Cr-Cu-Au, and Cu balls plated with Ni and Au are placed on the electrode base to form bumps welded by solder. This method is not suitable for a chip having a large number of electrodes because it is connected via Cu balls.

Therefore, an improved version of this system is also a controlled collapse reflow chip. This is one in which hemispherical bumps are formed by using Sn-Pb instead of the Cu balls of the above method. The bump is formed on the Al pad via a barrier metal (Cr-Cu-Au). In order to prevent excessive solder flow during bonding, a chip having a pad that is not connected to internal wiring has been devised.

Flip chips made of Al or Ag-Sn bumps are easy to work with Al and Ag alloys.
It is used because it is easy to obtain bonding conditions. The manufacturing method is the same as the above-mentioned ball method until the wafer having the internal wiring is covered with the glass film or the SiO ₂ film and the window for the electrode is opened by the photoresist technique. next,
After thinly depositing Cr or Ti as an adhesive metal,
The bump metal is attached and the bump portion is left to be removed by etching. The adhesion thickness of the bump metal is determined by the balance between the etching yield and the bondability, and is generally about 25 μm. Also, the size of the bump is limited by the chip size. There is also a flip chip using solder instead of Al and Ag—Sn.

An example of the flip-chip technology is "IC mounting technology" issued by the Industrial Research Institute Co., Ltd.
Published January 15, 1980 P81, P103 to P10
There are five.

[0007]

However, in the conventional flip-chip type semiconductor device, since the repeated stress acts on the connection terminal portion based on the difference in the thermal expansion coefficient between the pellet and the substrate, the pellet substrate There is a problem that peeling or cracking occurs in the connection terminal portion due to temperature cycling during bonding to the semiconductor device, during environmental testing of the semiconductor device, or during operation.

Therefore, in order to reduce the thermal stress due to the difference in the thermal expansion coefficient, the thermal expansion coefficient of the substrate is adjusted to the thermal expansion coefficient of the pellet as much as possible. In the case of this solution, since the selection condition of the substrate is determined by the thermal expansion coefficient, other physical properties other than the thermal expansion coefficient such as thermal conductivity, insulation performance, dielectric constant, adhesion with wiring, hygroscopicity, etc. However, there is a problem in that a material having excellent properties cannot be used as a substrate forming material.

An object of the present invention is to provide a semiconductor device capable of preventing the occurrence of cracks and peeling at a connection terminal due to stress associated with the difference in thermal expansion coefficient while avoiding restrictions on the substrate regarding the thermal expansion coefficient. It is in.

As a mounting technique for mounting pellets having bumps on a mounting substrate, an anisotropic conductive film is bonded to the mounting substrate, and the pellets are placed on the anisotropic conductive film with the bump groups in contact. At the same time, there is a technology to electrically connect the pellets to the mounting board through the electrical paths of the bumps and the anisotropic conductive film by pressing the bumps against the anisotropic conductive film by contraction of the photo-curable adhesive. ,Proposed.

However, in the semiconductor device using this anisotropic conductive film, the electrical connection between the pellet and the substrate is ensured by the contact between each bump and the anisotropic conductive film. However, there is a problem in that the inter-electrode pitch is restricted by the performance of the anisotropic conductive film.

A second object of the present invention is to provide a semiconductor device which can surely electrically connect the pellet and the substrate and can set the pitch between the electrodes small.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0014]

The typical ones of the inventions disclosed in the present application will be outlined below.

That is, in a semiconductor device in which a semiconductor pellet having an electronic circuit built therein is electrically connected to an insulating substrate via a connection terminal, a stress absorbing member is interposed between the semiconductor pellet and the insulating substrate. The stress absorbing member is made of a material having a small elastic modulus and is formed into a flat plate shape. A plurality of conducting members made of a conductive material are insulated from each other and have a thickness. The connection terminals are electrically connected to one end of each conductive member of the stress absorbing member, and the electric wiring of the insulating substrate is electrically connected to the other end of the stress absorbing member.

[0016]

According to the above-mentioned means, since the stress absorbing member is interposed between the semiconductor pellet and the insulating substrate, the mechanical stress generated by the difference in the thermal expansion coefficient between the semiconductor pellet and the substrate is absorbed by the stress absorbing member. It is absorbed by the deformation of the member. Due to the deformation absorbing action of this stress absorbing member,
Since it is possible to prevent the stress generated based on the difference in thermal expansion coefficient between the semiconductor pellet and the substrate from concentrating on the connection terminal, it is possible to prevent peeling or cracks from occurring at the connection terminal.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an enlarged partial sectional view showing a semiconductor device according to an embodiment of the present invention, and FIGS. 2A and 2B are perspective views and enlarged partial sectional views showing a semiconductor pellet used therein. 3 (a) and 3 (b) are partially cut perspective views and enlarged partial sectional views showing a substrate used in the semiconductor device of FIG. 1, and FIG. 4 is stress absorption used in the semiconductor device of FIG. 6 is a partially cutaway perspective view showing a member, FIG. 5 is a front sectional view showing an assembly of a pellet and a stress absorbing member, FIG.
(B) is each explanatory view for explaining a stress generation preventive action.

In this embodiment, in the semiconductor device according to the present invention, a silicon pellet (hereinafter referred to as a pellet) 11 as a semiconductor pellet in which an integrated circuit is built is used.
Computer module substrate (hereinafter referred to as substrate) 2
1 is electrically connected via a stress absorbing member 41, and each electrode pad of the pellet 11 is mechanically and electrically connected to each conducting member 43 of the stress absorbing member 41 by a plurality of connecting terminals 34 formed by CCB. It is configured to be electrically connected. The greatest feature of this semiconductor device is that the stress absorbing member 41 is provided between the pellet 11 and the substrate 21.

The semiconductor device is manufactured by the following manufacturing method. Hereinafter, a method of manufacturing this semiconductor device will be described. This description clarifies details of the configuration of the semiconductor device.

In this embodiment, the pellet 11 shown in FIG. 2 is used, and a plurality of bumps 12 for forming the connection terminal 34 are formed on the main surface of the connection side of the pellet 11.
It is formed by being arrayed in an array at a predetermined interval. The manufacturing work of pellets and bumps is performed in the form of a wafer in a so-called pre-process in the manufacturing process of a semiconductor device. Hereinafter, the manufacturing process of the pellets will be briefly described, mainly the forming process of the bumps 12.

In a pre-process of a so-called semiconductor device manufacturing process, a desired integrated circuit (not shown) is formed in a wafer form so as to correspond to each pellet 11. Next, in the electric wiring forming step, the electric wiring 14 is formed on the insulating film 13 of the integrated circuit. Aluminum is used for the work of forming the electric wiring 14, and the work is performed by an appropriate thin film forming process such as sputtering or vapor deposition and a lithographic process. A passivation film 15 is deposited on the electric wiring 14. Usually, the passivation film 15 is composed of a hard insulating film such as a silicon oxide film or a silicon nitride film.

The passivation film 15 has a plurality of through-holes 16 (in this embodiment, nine are shown for convenience, but a large number such as 640 are actually arranged), but they are mutually arranged. They are arranged in predetermined places at intervals and opened respectively. The predetermined electric wiring 14 is exposed on the bottom surface of each through hole 16 that is opened,
Therefore, the through hole 16 causes the electrode pad 16A
Is substantially configured. The work of opening the through hole 16 is selectively performed by a lithography process.

Thereafter, in the bump forming process, a thin film forming process and a lithographic process are used to electrically connect the bumps 12 to the electrode pads 16A, that is, the electric wirings 14 in the through holes 16 of the pellet 11. To be formed respectively. For example, the bump 12 includes a first underlayer 17 made of chromium, a second underlayer 18 made of copper, a third underlayer 19 made of gold, and a main body 20 made of a solder material (Sn-Pb). ing. In this embodiment, the main body 20 has Sn: Pb
The solder material for high temperature of 8: 2 is used to form a hemispherical shape having a diameter of about 100 μm.

The wafer on which the pellets 11 and the bumps 12 are formed as described above is divided into each pellet 11 in the dicing process. The pellet 11 after being diced is formed into a minute flat plate shape corresponding to a pellet mounting region on a substrate 21 described later. For example, the pellet 11 is formed in a square flat plate shape of 15 mm × 15 mm.

On the other hand, in this embodiment, the substrate 21 shown in FIG. 3 is used. Next, the configuration of the substrate 21 will be described.

The substrate 21 is provided with a base 22 formed of alumina ceramic, and the base 22 is formed in a rectangular board shape having appropriate strength and size so that it can be used as a computer module substrate. There is. In the present embodiment, alumina ceramic is used as the constituent material of the base 22, but not limited to this, it is possible to use ceramics such as silicon carbide, mullite, aluminum nitride, and insulating materials such as epoxy resin. ..

A first insulating layer 23 is laminated on the base 22, and the first insulating layer 23 is made of polyimide resin and is formed in a film shape. This first insulating layer 2
A first electric wiring (hereinafter, referred to as a first wiring) 24 is provided on the surface 3.
Are patterned into a desired shape and wired. In the present embodiment, the first wiring 24 is formed by joining a copper foil on the first insulating layer 23 using titanium as an adhesion metal and selectively patterning by a lithography process.

The second insulating layer 2 is formed on the first insulating layer 23.
5 is laminated, and the second insulating layer 25 is formed in a film shape using a polyimide resin like the first insulating layer 23. On this second insulating layer 25, a second electric wiring (hereinafter, referred to as a second wiring) 26 is patterned and wired in a desired shape. The second wiring 26 is
It is formed similarly to the first wiring 24.

Further, a plurality of through holes 27 are formed in the second insulating layer 25 by a lithographic process, and each through hole 27 exposes a predetermined electrode portion of the first wiring 24. .. The through-hole conductor 28 is made of the same conductive material as that of the first wiring 24 for each through-hole 27.
It is filled by an appropriate means such as a plating method. Each through-hole conductor 28 has one end (hereinafter referred to as a lower end) electrically connected to each electrode portion of the first wiring 24, and has an upper end at the second insulating layer 2.
5 is exposed.

A protective insulating layer 29 is laminated on the second insulating layer 25. The protective insulating layer 29 is made relatively thick using a polyimide resin which is an example of an insulating material having a small lateral elastic modulus. ing. Incidentally, in this embodiment, the protective insulating layer 29 is formed to have a thickness of about 200 μm by the successive laminating method.

The second through hole 3 is formed in the protective insulating layer 29.
A plurality of 0s are formed by the lithography process, and each second through hole 30 exposes each through hole conductor 28 of the first wiring 24 and a predetermined electrode portion of the second wiring 26. ing. The second through-hole conductor 31 is filled with the second through-hole conductor 31 using the same material as that of the wirings 24 and 26, and is filled by an appropriate means such as a vapor deposition method, a sputtering method, or a plating method. The lower ends of the through-hole conductors 31 are electrically connected to the first through-hole conductors 28 and the electrodes of the second wiring 26, respectively, and the upper ends thereof are exposed on the protective insulating layer 29. It is in a state of being.

CCB pads 32 are formed on the upper ends of the respective second through-hole conductors 31. Each pedestal 33 is formed on each pad 32 for ensuring soldering with a stress absorbing member, which will be described later. In this pedestal 33, Sn: Pb is 6:
The low temperature soldering material of No. 4 is used. The pads 32 are arranged so as to correspond to the bumps 12 on the pellet 11, and the arrangement group is arranged for the number of pellets 11 mounted on the substrate 21. In this embodiment, the pad 3
The second group is a pellet 11 of 15 mm square with a distance between bumps 12.
Are arranged such that the arrangement pitch of the pellets 11 is 12 mm.

Further, in this embodiment, the stress absorbing member 41 shown in FIG. 4 is used. Next, the structure of the stress absorbing member will be described.

The stress absorbing member 41 includes a main body 42 formed of soft silicone rubber which is an example of an insulating material having a small elastic modulus.
It is formed in a square flat plate shape having a size substantially equal to. The thickness of the main body 42 is preferably thin from the viewpoint of mounting form, but is preferably thick from the viewpoint of a stress absorbing action described later. Therefore, it is desirable that the thickness of the main body 42 is set to the thinnest within a range in which the stress absorbing action described later can be sufficiently secured.

A plurality of wires 43 as conducting members are planted in the stress absorbing member main body 42 so as to extend in the thickness direction. The pitch of the wires 43 is set so as to correspond to the bumps 12 of the pellet 11 and the pads 32 of the substrate 21. The wire 43 is formed using gold, which is an example of a conductive material, and its thickness is set to be substantially equal to the diameter of the bump 12. The tip of the wire 43 is a mixed solution of 10 g of iodine, 40 g of ammonium iodide, 100 l of ethanol, and 400 ml of pure water at 25 ° C.
In, the etching process is performed for about 10 seconds.

A specific method of manufacturing the stress absorbing member 41 in which the wire 43 is implanted in the main body 42 is as follows.
For example, there is a method in which a group of wires 43 is insert-molded when the body 42 is molded with silicone rubber, and then the body 42 is cut into a predetermined thickness together with the inserted group of wires 43.

As a method of manufacturing the stress absorbing member in which the conductive member is implanted in the main body, for example, a through hole is formed in the main body by an appropriate means such as a lithographic process or a laser process, and then the conductive member is formed. There is also a method of forming a conductive member by filling a conductive material such as gold into the through hole by an appropriate means such as vapor deposition or plating.

In the CCB process, the pellets 11 having the above structure are gang bonded to the stress absorbing member 41 manufactured as described above, as shown in FIG. That is, the pellets 11 are aligned with the stress absorbing member 41 and are temporarily bonded in a face-down state in which the bumps 12 are aligned with the wires 43 that have been pre-soldered.

Thereafter, the solder body 20 of each bump 12 is melted by an appropriate reflow process, so that each connection terminal 34 is simultaneously formed as shown in FIG. At this time, since the solder body 20 is made of a high temperature solder material, a relatively high temperature heat treatment is performed. With this group of connection terminals 34,
Each pellet 11 is mechanically connected to the stress absorbing member 41, and its integrated circuit is electrically connected to each wire 43 via the connection terminal 34. In this way, the assembly 44 of the pellet and the stress absorbing member shown in FIG. 5 is manufactured.

The assembly 44 thus manufactured is
In the CCB process, gang bonding is performed on the substrate 21 having the above structure as shown in FIG. That is, in a face-down state in which the lower end surfaces of the wires 43 of the stress absorbing member 41 are aligned with the pedestals 33 of the board 21, the assemblies 44 are aligned with the rows of the pads 32 of the board 21, and To be glued.

Thereafter, each pedestal 33 is melted by an appropriate reflow process, so that each connection terminal 45 is simultaneously formed as shown in FIG. At this time, since the pedestal 33 is made of a low temperature solder material, a relatively low temperature heat treatment is performed. Therefore, the first connection terminal 34 previously soldered with the high-temperature solder material does not melt in the subsequent soldering process.

By forming the second group of connection terminals 45,
Each pellet 11 is mechanically connected to the substrate 21 with the stress absorbing member 41 interposed, and the integrated circuit has a first connection terminal 34, a wire 43, a second connection terminal 45, and a through connection. It is in a state of being electrically connected to the first wiring 24 and the second wiring 26 of the substrate 21 through the hole conductors 31 and 28. In this way, the semiconductor device shown in FIG. 1 is manufactured.

Next, the operation will be described. Silicon and alumina ceramics have different coefficients of thermal expansion. That is, the coefficient of thermal expansion of silicon is about 3.5 to 4.0 × 10 ⁻⁶ (1 / °).
K), the coefficient of thermal expansion of alumina ceramic is about 7.2 ×
It is 10 ⁻⁶ (1 / ° K). In addition, the coefficient of thermal expansion of the low thermal expansion polyimide insulating layer is 3.5 to 5.0 × 10 ⁻⁶ (1
/ ° K), the coefficient of thermal expansion of copper wiring is 17 × 10 ^-6 (1 /
° K). The thermal expansion coefficient of the substrate 21 in the present embodiment is a composite value of these, and is approximately equal to the thermal expansion coefficient of the alumina ceramic base 22.

Therefore, when the pellet 11 and the substrate 21 are rigidly connected by the connection terminal 34, CCB
At the same time, when a large thermal fluctuation is applied during operation of the semiconductor device or the like, a large difference occurs in the expansion deformation amount and the contraction deformation amount between the pellet 11 and the substrate 21, so that the connection terminal 34 Stress is applied to the connection terminal 34
The present inventor has clarified that there is a problem that peeling and cracks occur in the. In particular, when the pellet size is as large as 10 mm □ or more, peeling and cracking tend to be remarkable.

FIG. 6 (a) is an explanatory view for explaining the mechanism of this peeling or cracking, in which the pellet 11 is rigidly coupled to the substrate 21 by the connection terminal 35 formed by using the solder bump. The state of the conventional example is shown.

As shown in FIG. 6A, for example, when the expansion position of the pellet 11 and the expansion position of the substrate 21 during CCB are lowered to room temperature, the expansion positions of the pellet 11 and the expansion position of the substrate 21 respectively contract due to the difference in thermal expansion coefficient. Trying to be in position. At this time,
The contraction difference between the pellet 11 and the substrate 21 affects each other to generate a strain, and the stress acts on the conventional connection terminal 35 formed by the solder bump.

Now, consider a case where the pellet 11 is not deformed and the substrate 21 is deformed. The deformation occurring only in the substrate 21 causes a stress corresponding to (proportional to) the deformation. The stress is applied to the connection terminal 35 as an illegal mechanical force, and a strain corresponding to the stress is generated in the connection terminal 35.

FIG. 6A shows the state of stress generation in the connection terminal 35. For the sake of clarity, the pellet 11 shall not be deformed. As understood from FIG. 6A, large stress is generated in each connection terminal 35 located in the peripheral portion of the pellet 11.

However, since the connection terminals 35 formed by the conventional solder bumps cannot follow the deformation of the substrate 21 due to the influence of the rigidity of the pellets 11, stress is applied to each connection terminal 35, and the connection terminals 35 themselves have strength and elastic deformation. When the adhesion limit with the pad 32 is exceeded, cracking or peeling occurs.

In view of the above principle, in this embodiment, as shown in FIG. 1, the pellet 11 and the substrate 2
Since the stress absorbing member 41 based on the soft main body 42 formed of silicone rubber is interposed between the pellet 11 and the pellet 11, the pellet 11 and the pellet 11 due to the difference in thermal expansion coefficient during thermal fluctuation are provided. The difference in the amount of deformation from the substrate 21 is absorbed by the elastic deformation of the stress absorbing member body 42. As a result, peeling and cracking of the connection terminals 34 are prevented.

That is, during CCB, the substrate 21 is greatly expanded and deformed as compared with the pellet 11 due to the difference in thermal expansion coefficient between the pellet 11 and the substrate 21, as shown in FIG. 6B. However, in this embodiment, since the pellets 11 are bonded on the stress absorbing member main body 42 made of soft silicone rubber, the entire stress absorbing member 41 is formed as shown in FIG. 6B. Due to the elastic deformation of the main body 42 made of soft silicone rubber, the deformation difference between the pellet 11 and the substrate 21 is absorbed.

In this way, the stress absorbing member 41 is elastically deformed so as to absorb the difference in deformation between the pellet 11 and the substrate 21, so that the connecting terminals 34 and the connecting terminals 34 formed between the pellet 11 and the substrate 21, respectively. No stress that exceeds the strength, elastic deformation limit, or adhesion limit of these connection terminals 34 and 45 acts on 45. As a result, the phenomenon that peeling or cracks occur in the connection terminals 34 and 45 due to stress is prevented in advance.

The semiconductor device according to this example was subjected to a temperature cycle test with a temperature cycle period of 1 cycle / hour and a temperature range of −50 ° C. to 100 ° C. No disconnection due to thermal fatigue occurred in each of the connection terminals 34 and 45 on both sides of the absorbing member 41.

According to the above embodiment, the following effects can be obtained. By interposing a soft stress absorbing member between the substrate and the pellet, the connection terminals with the pellet on both sides of the wire planted in the stress absorbing member, and by forming the connection terminal with the substrate, respectively, Since the difference in the deformation amount between the substrate and the pellet at the time of thermal fluctuation based on the difference in thermal expansion coefficient between the alumina ceramic and silicon can be absorbed by the elastic deformation of the soft stress absorbing member, the connection can be made by the difference in the deformation amount. The stress acting on the terminals can be suppressed or suppressed, and as a result, the occurrence of peeling or cracks in the connection terminals formed by CCB can be prevented.

By preventing peeling or cracking of the connection terminal due to CCB, the yield of the semiconductor device due to CCB can be increased, and its quality and reliability can be improved.

By forming the soft stress absorbing member main body using silicone rubber, it is possible to suppress the cost increase to a small extent and to configure a stress absorbing member having an extremely large elastic limit.

FIG. 7 is an enlarged partial sectional view showing a semiconductor device according to another embodiment of the present invention, and FIGS. 8A and 8B are perspective views and enlarged partial sectional views showing pellets used therein. 9 (a) and 9 (b) are partially cut perspective views and enlarged partial sectional views showing the same substrate, FIG. 10 is a partially cut perspective view showing the same stress absorbing member, and FIG. 11 is a pellet and a stress absorbing member. FIG. 3 is a front sectional view showing the assembly of FIG.

The semiconductor device according to the second embodiment is different from the semiconductor device according to the first embodiment in that light is emitted between the pellet 11A and the stress absorbing member 41A and between the substrate 21A and the stress absorbing member 41A. Curable insulating resin layers 51 and 52
It is in the point that they are respectively joined by.

This semiconductor device is manufactured by the following manufacturing method. Hereinafter, a method of manufacturing this semiconductor device will be described. This description clarifies details of the configuration of the semiconductor device.

In this embodiment, the pellet 11A shown in FIG. 8 is used. This pellet 11A differs from the pellet 11 of the first embodiment in that the bump 12A
The main body 20A is formed in a disk shape.

Further, in this embodiment, the substrate 21A shown in FIG. 9 is used. This substrate 21A is different from the substrate 21 of the first embodiment in that the pedestal 33 on the pad 32 is eliminated, and the substrate 21A is different from the wirings 24, 26, the through-hole conductors 28, 31 and the pad 32. Therefore, it is configured so that it can transmit light as a whole.

Further, in this embodiment, the stress absorbing member 41A shown in FIG. 10 is used. This stress absorbing member 41A is different from the stress absorbing member 41 of the first embodiment in that both ends of the wire 43A are provided so as to project from the upper and lower surfaces of the main body 42, respectively, and that the main body 42 can transmit light. The point is that it is configured.

The stress absorbing member 4 configured as described above
The pellet 11A having the above structure is joined to the 1A by a photo-curable insulating resin layer 51 as shown in FIG. That is, the pellets 11 are face down with the bumps 12A aligned with the wires 43A.
A is aligned with the stress absorbing member 41A,
A photocurable insulating resin is filled between the mating surfaces of the pellet 11A and the stress absorbing member 41A, and is temporarily bonded.

Thereafter, the pellet 11A and the stress absorbing member 4 are irradiated with light from the stress absorbing member 41A side.
The insulating resin filled between 1A and 1A is cured and the resin layer 5
1 is formed. Since the resin layer 51 contracts by being hardened, the contracting force causes the pellets 11A and the stress absorbing member 41A adhered to both sides of the resin layer 51 to be bonded while being close to each other. Therefore, in this bonded state, the projecting end surface of the wire 43A of the stress absorbing member 41A has the electrode pad 16 of the pellet 11A.
It is in a state of being strongly pressed against A. That is, the wire 43
The protruding end portion of A is in a state of substantially forming the connection terminal 34A electrically connected to the electrode pad 16A of the pellet 11A.

As shown in FIG. 7, the pellet-stress-absorbing member assembly 44A manufactured as described above has the second photo-curable insulating resin layer 52 on the substrate 21A having the above structure. To be joined. That is, the stress absorbing member 4
Each assembly 44A is aligned with each pad group row of the board 21A and the board 21 and the stress absorbing member in a face-down state in which the protruding end surfaces of the wires 43A of the board 1A are aligned with the pads 32 of the board 21A. A photo-curable insulating resin is filled between the mating surfaces with 41A and temporarily bonded.

After that, by irradiating light from the substrate 21 side, the insulating resin filled between the substrate 21 and the stress absorbing member 41A is cured to form the second resin layer 52. Since the resin layer 52 contracts as it hardens, the contraction force causes the substrate 21 and the stress absorbing member 41 to contract.
It will be joined with A while approaching each other. Therefore, in this joined state, the stress absorbing member 41A
The protruding end surface of the wire 43A is strongly pressed against the pad 32 of the substrate 21A. That is, the protruding end portion of the wire 43A substantially forms the connection terminal 45A electrically connected to the pad 32 of the substrate 21A.

As described above, the semiconductor device shown in FIG. 7 is manufactured. This semiconductor device
Since the soft stress absorbing member 41A is interposed between the pellet 11A and the substrate 21A, the same action and effect as those of the first embodiment can be obtained.

FIG. 12 is an enlarged partial sectional view showing a semiconductor device which is Embodiment 3 of the present invention.

The third embodiment differs from the first embodiment in that
Substrate 21B of wire 43B in stress absorbing member 41B
The side end portion 45B is projected long, and the protruding end portion 45B
B is inserted into the insertion opening 36 formed in the substrate 21B and electrically connected to the pad 32B.

Also in the third embodiment, since the soft stress absorbing member 41B is provided between the pellet 11B and the substrate 21B, the same operation and effect as those of the first embodiment can be obtained. ..

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, as the material having a low elastic modulus for forming the soft stress absorbing member main body, not only silicone rubber but also soft epoxy resin or polyimide resin may be used.

The material for forming the conductive member of the stress absorbing member is not limited to gold, but conductive materials such as copper, aluminum, silver, palladium, platinum and alloys thereof may be used.

The electric wiring layer is not limited to two layers,
It may be formed in one layer, or may be formed in three or more layers.

The method of flip chip bonding the pellet to the stress absorbing member and the stress absorbing member to the substrate is not limited to the CCB method, but other flip chip methods may be used.

In the above description, the case where the invention made by the present inventor is mainly applied to the semiconductor device used for the module of the computer which is the field of application of the background has been described, but the invention is not limited to this. It can be applied to all semiconductor devices in which pellets are bonded to a substrate by a flip chip method. In particular, the present invention is applied to the case where the difference in thermal expansion coefficient between the pellet and the substrate is large and the pellet size is large, and excellent effects can be obtained.

[0077]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

A stress absorbing member having a small elastic modulus is interposed between the substrate and the pellet, and a connecting terminal with the pellet and a connecting terminal with the substrate are formed on both sides of the wire implanted in the stress absorbing member. By doing so, the difference in the deformation amount between the substrate and the pellet at the time of thermal fluctuation based on the difference in expansion coefficient between the substrate constituent material and the pellet constituent material can be absorbed by the elastic deformation of the soft stress absorbing member. Therefore, it is possible to suppress or suppress the stress acting on the connection terminal due to the difference in deformation amount, and as a result, it is possible to prevent peeling or cracks from occurring in the connection terminal.

[Brief description of drawings]

FIG. 1 is an enlarged partial sectional view showing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a perspective view and an enlarged partial sectional view showing a semiconductor pellet used therein.

FIG. 3 is a partially cut perspective view and an enlarged partial sectional view of the same substrate.

FIG. 4 is a partially cutaway perspective view showing the stress absorbing member.

FIG. 5 is a front sectional view showing an assembly of a pellet and a stress absorbing member.

FIG. 6 is an explanatory diagram for explaining a stress generation preventing action.

FIG. 7 is an enlarged partial sectional view showing a semiconductor device according to another embodiment of the present invention.

FIG. 8 is a perspective view and an enlarged partial sectional view showing a semiconductor pellet used therein.

FIG. 9 is a partially cut perspective view and an enlarged partial sectional view showing the same substrate.

FIG. 10 is a partially cutaway perspective view showing the stress absorbing member.

FIG. 11 is a front sectional view showing an assembly of pellets and a stress absorbing member.

FIG. 12 is an enlarged partial cross-sectional view showing a semiconductor device which is Embodiment 3 of the present invention.

[Explanation of sign]

11, 11A ... Pellet, 12, 12A ... Bump, 13
... Insulating film, 14 ... Electrical wiring, 15 ... Passivation film, 16 ... Through hole, 16A ... Electrode pad, 17 ...
First underlayer, 18 ... Second underlayer, 19 ... Third underlayer, 2
0, 20A ... Bump body, 21, 21A, 21B ... Substrate, 22 ... Base, 23 ... First insulating layer, 24 ... First electrical wiring (first wiring), 25 ... Second insulating layer, 26 ... Second electrical Wiring (second wiring), 27 ... Through hole, 28 ... Through hole conductor, 29 ... Protective insulating layer, 30 ... Second through hole, 31 ... Through hole conductor, 32, 32B ... Pad, 33 ... Pedestal, 34, 34A ... Connection terminal, 35
... Connecting terminals using conventional solder bumps, 41, 41A,
41B ... Stress absorbing member, 42, 42A, 42B ... Soft body, 43, 43A, 43B ... Wire (conducting member), 4
4, 44A ... Assembly of pellet and stress absorbing member, 45,
45A, 45B ... Connection terminals, 51, 52 ... Photocurable insulating resin layer.

Claims (4)

[Claims] 1. A semiconductor device in which a semiconductor pellet having an electronic circuit built therein is electrically connected to an insulating substrate via a connection terminal, wherein a stress absorbing member is interposed between the semiconductor pellet and the insulating substrate. This stress absorbing member is made of a material having a small elastic modulus and is formed into a flat plate shape. A plurality of conducting members made of a conductive material are insulated from each other to have a thickness. And the electrical connection of the insulating substrate is electrically connected to one end of each conductive member of the stress absorbing member and the other end thereof. apparatus. 2. The connection terminals are formed by soldering bumps, which are formed by projecting a conductive material on the electrode pads of the semiconductor pellet, to a conductive member of the stress absorbing member. The semiconductor device according to claim 1, wherein: 3. The semiconductor pellet and the stress absorbing member, and the insulating substrate and the stress absorbing member are joined by a photo-curable insulating resin, respectively. The semiconductor device described. 4. The semiconductor device according to claim 1, wherein the conductive member of the stress absorbing member is inserted into a through hole provided in an insulating substrate and connected to an electric wiring.