JP3675374B2 - Semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device in which electrodes of two semiconductor chips are connected to each other by bumps, and in particular, by making bump sizes formed on a plurality of electrodes of one semiconductor chip equal to each other. The present invention relates to a semiconductor device in which the reliability of bonding between electrodes of two semiconductor chips is improved.
[0002]
[Prior art]
In recent years, in order to reduce the cost and size of a semiconductor device, there has been proposed a semiconductor device in which LSI chips having different functions or LSI chips formed by different processes are joined together in a face-down manner. ing.
[0003]
Hereinafter, a conventional semiconductor device will be described with reference to the drawings.
[0004]
FIG. 4 is a cross-sectional view showing a conventional semiconductor device.
[0005]
As shown in FIG. 4, the first bump 3 made of Ni formed by the electroless plating method on the electrode 2 of the first semiconductor chip 1, and the internal electrode 5 of the second semiconductor chip 4 and the outside The barrier metal 7 of the second semiconductor chip and the second bump 8 made of solder are formed on the electrode 6 and the internal electrode 5, and the second bump 8 made of solder becomes the first bump 3 made of Ni. Electrically joined in a covered state.
[0006]
Here, the sizes of the electrodes 2 of the first semiconductor chip 1 are different from each other. The volume of the first bump 3 formed on the electrode 2 of the first semiconductor chip 1 is proportional to the size of the electrode 2 on which each first bump is formed. As for the sharpness, the tip of the first bump 3 becomes sharper as the size of the electrode 2 of the first semiconductor chip 1 is smaller.
[0007]
Accordingly, in this conventional example, the right electrode of the two first electrodes is smaller, and therefore the first bump 3 formed on the right electrode 2 is formed on the left electrode 2. It becomes sharper than the bump 3 and the inner angle of the right first bump 3 tip becomes smaller.
[0008]
Further, an insulating resin 9 is filled between the first semiconductor chip 1 and the second semiconductor chip 4, and the first semiconductor chip 1 and the second semiconductor chip 4 have the first bumps. 3 and the second bump 8 and the insulating resin 9 are integrated.
[0009]
Then, the second semiconductor chip 4 is fixed to the die pad 10 of the lead frame by the die bond resin 11, and the external electrode 6 of the second semiconductor chip 4 and the external lead 12 of the lead frame are electrically connected through the fine metal wires 13. It is connected. The first semiconductor chip 1, the second semiconductor chip 4, the fine metal wire 13, the die pad 10, and a part of the external lead 12 are sealed with a sealing resin 14.
[0010]
Next, a method for manufacturing the semiconductor device will be described.
[0011]
FIG. 5 is a cross-sectional view showing each step of a conventional method for manufacturing a semiconductor device.
[0012]
As shown in FIG. 5A, first bumps 3 made of Ni are formed on the electrodes 2 of the first semiconductor chip 1 by electroless plating. Also, second bumps 8 made of solder are formed on the internal electrodes 5 of the second semiconductor chip 4 by electrolytic plating. Regarding the formation of the second bumps 8 made of solder, after the barrier metal 7 is formed on the second semiconductor chip 4 by vapor deposition, a bump pattern is formed by resist and the second bumps 8 are formed by electrolytic solder plating. Then, after the barrier metal 7 is dissolved and removed by wet etching using the second bumps 8 made of solder as a mask, the second bumps 8 made of solder are reflowed to be hemispherical.
[0013]
Next, as shown in FIG. 5 (b), the first bump made of Ni of the first semiconductor chip 1 coated with the insulating resin 9 on the second semiconductor chip 4 and vacuum-adsorbed to the connection tool 15. 3 and the second bump 8 made of Ni on the internal electrode 5 of the second semiconductor chip are matched.
[0014]
Next, as shown in FIG. 5C, the first semiconductor chip 1 is placed on the second semiconductor chip 4, the second bumps 8 made of solder are melted by heating, and the first semiconductor chip 1 made of Ni is melted. The bump 3 is joined.
[0015]
Finally, as shown in FIG. 5D, the second semiconductor chip 4 is die-bonded to the die pad 10 of the lead frame, and the external electrode 6 of the second semiconductor chip 4 and the external lead 12 of the lead frame are connected to the thin metal wire 13. And are sealed with a sealing resin 14.
[0016]
[Problems to be solved by the invention]
However, when the size of the electrode of the first semiconductor chip is different, the conventional semiconductor device and the manufacturing method thereof vary in the sharpness of the tip of the bump formed on the electrode, that is, the inner angle of the bump tip. When the bump tip is not sharp, the depth at which the first bump bites into the bump formed on the internal electrode of the second semiconductor chip is small, and it is difficult to ensure sufficient bonding strength.
[0017]
Therefore, in the conventional semiconductor device and the manufacturing method thereof, when the size of the electrode formed on the first semiconductor chip varies, the sharpness of the tip of the bump formed on the internal electrode of the first semiconductor chip is increased. The property (inner angle) is not constant, and the bonding strength of the bonding portions between the bumps varies, and it is a problem to sufficiently secure the bonding strength in all the bonding portions.
[0018]
The present invention is for solving the above-mentioned problems. By unifying and reducing the size of the electrode, the sharpness of the bump tip (inner angle) is sharpened, and the sharpness variation is reduced. The present invention provides a suppressed semiconductor device and a manufacturing method thereof.
[0019]
[Means for Solving the Problems]
In order to solve the conventional problems, a semiconductor device of the present invention includes a plurality of electrodes size formed on the first semiconductor chip is different, is formed on the first semiconductor chip, said plurality second bump and the electrode insulating resin having an opening on each of a plurality of first bumps formed on the plurality of electrodes, a plurality of formed in the internal electrode of the second semiconductor chip with the door, for all of the plurality of electrodes of different sizes, the size of the opening is the same, the size of each other the plurality of first bumps are the same, the plurality of first bump plurality Each of the second bumps bites into and is connected.
[0020]
Further, the shapes of the first bumps are the same.
[0022]
Therefore, even if the sizes of the electrodes of the first semiconductor element are different, the sizes or shapes of the plurality of electrodes of the first semiconductor element can be unified, so that the electrodes having the unified size or shape are formed. The bumps have the same size or shape, and the amount of biting of the plurality of first bumps into the second bumps is constant. Therefore, it is possible to stably secure the bonding force at the bonding portion between the first bump and the second bump. Moreover, since the opening size of the electrode of the first semiconductor element can be reduced by forming the insulating resin on the electrode of the first semiconductor chip, the bumps formed on the electrode of the first semiconductor chip can be reduced. The sharpness of the tip becomes sharp, the amount of biting of the first bump with respect to the second bump increases, and the bonding strength between the first bump and the second bump can be improved.
[0023]
The material of the first bump is any one of Ni, Au, Ag, Cu, Pd, and P.
[0024]
The material of the second bump is solder.
[0025]
Therefore, the first bumps can easily bite into the second bumps, and the bonding strength between the first bumps and the second bumps can be improved.
[0026]
In addition, the back surface of the second semiconductor chip is bonded to the die pad, and the external electrode and the lead of the second semiconductor chip are electrically connected by a thin metal wire.
[0027]
Accordingly, it is possible to mount semiconductor chips joined by bumps on the lead frame.
[0028]
According to another aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: forming an insulating resin on a plurality of electrodes of a first semiconductor chip to unify the sizes of openings of the plurality of electrodes; From the step of forming the first bump on the electrode of the chip, the step of forming the second bump on the internal electrode of the second semiconductor chip, and the step of biting the first bump into the second bump Become.
[0029]
Accordingly, the shapes of the plurality of first bumps can be unified, and the sharpness (inner angle of the front end) of the first bump can be made sharp and equivalent. The bonding strength at the connection portion between the first bump and the second bump can be increased.
[0030]
The first bump is formed by an electroless plating method.
[0031]
Thereby, the size or shape of the bump can be formed according to the size or shape of the electrode of the first semiconductor chip, and the size and shape of the bump can be controlled by adjusting the size and shape of the electrode. It becomes possible.
[0032]
Further, after the step of biting the first bump into the second bump, the step of bonding the back surface of the second semiconductor chip to the die pad, and the external electrode and the lead of the second semiconductor chip are electrically connected by a thin metal wire. And connecting them to each other.
[0033]
As a result, it is possible to realize a semiconductor device in which semiconductor elements are joined on a lead frame by bumps.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a semiconductor device and a manufacturing method thereof according to the present invention will be described.
[0035]
First, the semiconductor device of this embodiment will be described.
[0036]
FIG. 1 is a cross-sectional view showing the semiconductor device of this embodiment.
[0037]
As shown in FIG. 1, 16 is a first semiconductor chip, 17 is a protective film of the semiconductor chip, 18a and 18b are internal electrodes of the first semiconductor chip, 19 is an internal electrode of the second semiconductor chip, and 20 is a first semiconductor chip. 1 is a bump, 21 is a second semiconductor chip, 22 is an external electrode of the second semiconductor chip, 23 is a barrier metal of the second semiconductor chip, 24 is a second bump, 25 is an insulating resin, and 26 is a die bond resin. , 27 are external leads of the lead frame, 28 is a die pad of the lead frame, 29 is a fine metal wire, and 30 is a sealing resin.
[0038]
The first semiconductor chip 16 has an internal electrode 18a having a diameter of 100 [μm] and an internal electrode 18b having a diameter of 15 [μm], and has a first opening size having a diameter of 100 [μm]. An insulating resin 25 having an opening size of 15 [μm] in diameter is formed on the internal electrode 18a of the semiconductor chip 16, and a first semiconductor for forming the first bump 20 made of Ni by an electroless plating method. The openings on the internal electrodes 18a and 18b of the chip 16 all have the same size and shape, and the sizes of the plurality of first bumps 20 made of Ni are all formed equally.
[0039]
On the other hand, a square internal electrode 19 having a side of 70 [μm] and an external electrode 22 having a side of 80 [μm] are formed on the second semiconductor chip 21, and the second semiconductor chip 21 is formed on the internal electrode 19 of the second semiconductor chip. In addition, the Ti / Cu / Ni film thicknesses are sequentially formed to a thickness of 0.2 / 0.5 / 3 [μm], the barrier metal 23 is formed on the internal electrode 19 of the second semiconductor chip 21, and A second bump 24 made of Sn-3.5Ag solder having a diameter of 60 [μm] and a height of 40 [μm] is formed on the upper surface of the barrier metal 23. In addition, the first bump 20 made of Ni bites into the second bump 24 made of Sn-3.5Ag solder, and the first bump 20 and the second bump 24 are electrically joined, and the first bump 20 is made electrically. The semiconductor chip 16 and the second semiconductor chip 21 have a gap, and the gap is filled with an insulating resin 31 and integrated.
[0040]
Further, the back surface of the second semiconductor chip 21 is bonded to the die pad 28 of the lead frame with a die bond resin 26, and the external electrode 22 of the second semiconductor chip 21 and the external lead 27 of the lead frame are connected by a thin metal wire 29. The first semiconductor chip 16, the second semiconductor chip 21, the fine metal wires 29 and the die pad 28 are sealed with a sealing resin 30.
[0041]
As described above, in the semiconductor device of this embodiment, even if the size and shape of the electrode of the first semiconductor chip are different, the insulating resin is formed on the electrode of the first semiconductor chip, so that the opening size and the opening shape of the electrode are the same. By adjusting, the size and shape of the first bump formed on the electrode can be controlled. That is, the size and shape of the first bump are unified, and in particular, the sharpness of the tip of the first bump can be sharpened (the inner angle of the bump tip is small). The amount of biting into the second bump can be increased, and the bonding strength between the first bump and the second bump can be increased.
[0042]
Next, a method for manufacturing a semiconductor device of the present invention will be described.
[0043]
2 and 3 are cross-sectional views showing each step of the method of manufacturing a semiconductor device according to the present invention. For each figure number, a plan view and a cross-sectional view are shown in parallel. FIG. 2 shows a bump formation process, and FIG. 3 shows an assembly process.
[0044]
First, as shown in FIG. 2A, the size of the internal electrode 18a is larger than the size of the internal electrode 18b. The first semiconductor chip 16 is inspected by bringing a probe needle into contact with the internal electrode 18a. This is because an area for contacting the probe needle is necessary. After the probe inspection is completed, the insulating resin 25 is formed on the upper surfaces of the plurality of electrodes having different sizes or shapes of the openings, that is, the internal electrodes 18a and 18b of the first semiconductor chip 16.
[0045]
Next, as shown in FIG. 2B, the size and shape of the larger internal electrode 18a among the internal electrodes of the first semiconductor chip 16 are equivalent to the size and shape of the smaller internal electrode 18b. As shown, the insulating resin 25 formed on the upper surface of the larger internal electrode 18a is partially opened to remove the opening. As a result, in the present embodiment, a circular insulating resin 25 having a film thickness of about 1 [μm] and an opening of 15 [μm] is formed on the upper surface of the larger internal electrode 18a.
[0046]
Next, as shown in FIG. 2 (c), the first semiconductor chip 16 that has been pre-plated is immersed in the electroless plating tank 33 containing the electroless Ni plating solution 32 heated to 90 [° C.]. To do.
[0047]
Next, as shown in FIG. 2D, a first bump 20 made of Ni having a diameter of 30 [μm] and a height of 10 [μm] is formed by electroless plating.
[0048]
Next, as shown in FIG. 3A, first bumps 20 made of Ni are formed on the internal electrodes 18 a and 18 b of the first semiconductor chip 16 by electrolytic plating, and the inside of the second semiconductor chip 21. A second bump 24 is formed on the electrode 19 with Sn-3.5Ag solder. Regarding the formation of the second bump 24 made of Sn-3.5Ag solder on the second semiconductor chip 21, the barrier metal 23 is formed by vapor deposition on the wafer of the second semiconductor chip 21 to have a film thickness of 0.2 / 0.5. After forming Ti / Cu at [μm], an internal electrode 19 having a diameter of 50 [μm] is formed by a resist having a thickness of about 30 [μm], and the diameter is 50 [μm] with respect to the upper surface of the internal electrode 19. The second bump 24 having a diameter of 50 [μm] and a height of 30 [μm] is formed by electroplating Ni having a height of 3 [μm] and using Sn-3.5Ag solder as a material on the upper surface of the Ni plating. It is formed by electrolytic plating. Then, using the second bumps 24 formed of Sn-3.5Ag solder as a mask, the barrier metal 23 formed of Ti / Cu is dissolved and removed by wet etching using Ti for hydrogen peroxide and Cu for sulfuric acid, respectively. Further, the second bump 24 formed of Sn-3.5Ag solder is reflowed into a hemispherical shape at a reflow temperature of about 250 [° C.].
[0049]
Next, as shown in FIG. 3B, epoxy is used so as not to block the external electrode 22 of the second semiconductor chip 21 at the position where the first semiconductor chip 16 is mounted on the second semiconductor chip 21. Then, an insulating resin 31 such as polyimide or acrylic is applied, and the first bumps 20 of the first semiconductor chip 16 vacuum-adsorbed to the bonding tool 34 are bitten into the second bumps 24 of the second semiconductor chip 21. To join.
[0050]
Next, as shown in FIG. 3C, the first semiconductor chip 16 is turned into the second semiconductor chip 21 by the first bump 20 and the second bump 24 by heating through the bonding tool 34. Join. Thereafter, the second bump 24 made of Sn-3.5Ag solder is melted by heating to 200 to 270 [° C.], the first bump 20 formed of Ni is joined by soldering, and the insulating resin 25 is cured. To do. At this time, the gap between the surfaces of the first semiconductor chip 16 and the second semiconductor chip 21 is 2 to 30 [μm]. Here, by joining the first bump 20 into the second bump 24, the bonding strength between the first bump 20 and the second bump 24 can be increased.
[0051]
Next, as shown in FIG. 3D, the second semiconductor chip 21 to which the first semiconductor chip 16 is bonded is bonded to the die pad 28 of the lead frame to the die bond resin 26, and the second semiconductor chip 21 is bonded. The external electrode 22 and the external lead 27 of the lead frame are connected by a fine metal wire 29. Finally, the first semiconductor chip 16, the second semiconductor chip 21, the fine metal wire 29 and the die pad 28 are sealed with a sealing resin 30. 30 is sealed.
[0052]
【The invention's effect】
In the semiconductor device and the manufacturing method thereof according to the present invention, by covering a plurality of electrodes of a semiconductor chip with an insulating resin, the size or shape of the electrodes can be unified, and the size or shape of the bumps can be made equal. It becomes possible. Therefore, the amount of biting of the first bump relative to the second bump can be made equal and large, and a stable bonding force at the bonding portion between the first semiconductor chip and the second semiconductor chip via the bump. Can be secured.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a semiconductor device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing steps of a method for manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing a conventional semiconductor device manufacturing process. FIG. 5 is a cross-sectional view showing each process of a conventional semiconductor device manufacturing method.
DESCRIPTION OF SYMBOLS 1 1st semiconductor chip 2 Electrode 3 1st bump 4 2nd semiconductor chip 5 Internal electrode 6 External electrode 7 Barrier metal 8 2nd bump 9 Insulating resin 10 Die pad 11 Die bond resin 12 External lead 13 Metal fine wire 14 Sealing Resin 15 Tool for connection 16 First semiconductor chip 17 Protective films 18a and 18b for semiconductor chip Internal electrode 19 Internal electrode 20 First bump 21 Second semiconductor chip 22 External electrode 23 Barrier metal 24 Second bump 25 Insulation Resin 26 Die bond resin 27 External lead 28 Die pad 29 Metal thin wire 30 Sealing resin 31 Insulating resin 32 Electroless Ni plating solution 33 Electroless plating bath 34 Joining tool

Claims (5)

A plurality of electrodes size formed on the first semiconductor chip is different, is formed on the first semiconductor chip, an insulating resin having an opening on each of the plurality of electrodes, said plurality a plurality of first bumps formed on electrodes of a second semiconductor chip plurality of second bumps formed on the internal electrodes, for all of the plurality of electrodes of different sizes, the The openings have the same size, the plurality of first bumps have the same size, and the plurality of first bumps bite into and connect to the plurality of second bumps, respectively. Semiconductor device.   The semiconductor device according to claim 1, wherein the shapes of the first bumps are the same.   2. The semiconductor device according to claim 1, wherein the material of the first bump is any one of Ni, Au, Ag, Cu, Pd, and P.   The semiconductor device according to claim 1, wherein a material of the second bump is solder.   2. The semiconductor device according to claim 1, wherein a back surface of the second semiconductor chip is bonded to a die pad, and an external electrode and a lead of the second semiconductor chip are electrically connected by a thin metal wire.

Images