JP2001060658A - Semiconductor device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-type semiconductor device of chip-on-chip structure. SOLUTION: A slave chip D is joined on the surface of a master chip M facing downward. Protrudent electrodes T protruding from the surface of the maser chip M are provided around the slave chip D. The surface of the master chip D, where the heads of the protrudent electrodes T are exposed, is sealed up with a protective resin 11. This semiconductor device 10 of chip-on-chip structure can be manufacturing through a method where slave chips D are joined on the surface of a semiconductor wafer in a facedown mounting manner, protrudent electrodes T are formed, the surface of the semiconductor wafer is sealed up with the protective resin 11, and then the wafer is divided. After the surface of a wafer is sealed up with a protective resin 11, the protective resin is ground, by which the heads of the protrudent electrodes T can be made to expose surely. The rear surface of a wafer or the rear surface of a slave chip D is ground as necessary, by which a semiconductor device can be more reduced in thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a chip-on-chip structure in which another semiconductor chip is bonded on a semiconductor chip, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a semiconductor device having a chip-on-chip structure, for example, as shown in FIG. 3 is provided. Such a chip-on-chip structure is an advantageous structure for achieving high integration of the element. However, in addition to the thicknesses a and b of the parent chip 1 and the child chip 2, the external connection electrodes 3
Is a disadvantage that the overall height (a + b + c) is relatively high.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device having a chip-on-chip structure and having a reduced thickness, and a method of manufacturing the same.

[0004]

According to a first aspect of the present invention, there is provided a semiconductor device comprising: a first semiconductor chip and a second semiconductor chip bonded to a surface of the first semiconductor chip; And a projection electrode formed on the surface of the first semiconductor chip for connection to the outside, and sealing the surface of the first semiconductor chip with the head of the projection electrode exposed. And a protective resin for stopping the semiconductor device.

According to this structure, the second semiconductor chip is bonded to the surface of the first semiconductor chip, and the protruding electrode is formed on the same surface. The surface of the first semiconductor chip is formed on the surface of the protruding electrode. It is sealed with a protective resin with its head exposed. Therefore, the height of the entire semiconductor device can be reduced as compared with the case where external connection electrodes are provided on the back surface side of the first semiconductor chip, and a thin semiconductor device having a chip-on-chip structure can be realized.

[0006] The head of the protruding electrode may be flush with the protective resin, or the head of the protruding electrode may protrude from the surface of the protective resin. Further, as long as the head of the projecting electrode is exposed, the head of the projecting electrode may be depressed inward from the surface of the protective resin. The second semiconductor chip may be embedded in the protective resin,
A part of the inactive surface or side surface may be exposed from the protective resin.

According to a second aspect of the present invention, there is provided a chip bonding step of bonding a plurality of semiconductor chips to a surface of a semiconductor substrate in a face-down state with their active surfaces facing the surface of the semiconductor substrate; An electrode forming step of forming a plurality of projecting electrodes on the surface of the substrate; and protecting the surface of the semiconductor substrate, which is exposed after the formation of the semiconductor chip and the projecting electrodes, with the head of the projecting electrode exposed. And a cutting step of cutting out the semiconductor device having a chip-on-chip structure by cutting the semiconductor substrate along a predetermined cutting line. 6 shows a method for manufacturing a semiconductor device.

According to this method, a thin chip-on-chip type semiconductor device having the structure described in claim 1 can be manufactured. In this method, a plurality of semiconductor chips are bonded to the surface of the semiconductor substrate, and a plurality of protruding electrodes are formed on the same surface. Therefore, the bonding of the chips in the state of the semiconductor substrate (semiconductor wafer) is performed. And electrodes can be formed, and then cut into individual pieces of semiconductor devices with a chip-on-chip structure,
A plurality of chip-on-chip semiconductor devices can be manufactured efficiently.

The surface of the semiconductor substrate is resin-sealed with a protective resin, and the semiconductor chip is bonded face-down to the surface of the semiconductor substrate. It is enough. Therefore, a thin semiconductor package having a height close to the sum of the thicknesses of the semiconductor substrate and the semiconductor chip mounted thereon is realized. If necessary, the back surface of the semiconductor substrate or the back surface (inactive surface side) of the semiconductor chip may be polished or ground with a grinder or the like before the cutting step, so that a further reduction in thickness can be achieved.

According to a third aspect of the present invention, the resin sealing step includes an electrode exposing step of exposing a head portion of the projecting electrode by removing a surface layer of the protective resin. 3. A method for manufacturing a semiconductor device according to item 2. According to the present invention, the step of removing the surface layer of the protective resin to expose the head of the projecting electrode is included, so that the projecting electrode can be reliably exposed. The surface portion of the protective resin may be removed by grinding with a grinder or the like,
Other techniques such as etching may be used.

According to a fourth aspect of the present invention, the electrode exposing step includes a chip grinding step of simultaneously polishing or grinding the protective resin and the non-active surface side of the semiconductor chip. Is a method for manufacturing a semiconductor device. According to the present invention, by simultaneously polishing or grinding the protective resin and the non-active surface of the semiconductor chip, the head of the protruding electrode is reliably exposed, and the semiconductor chip can be made thinner.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing a configuration of a semiconductor device according to one embodiment of the present invention. The semiconductor device 10 includes a child chip D (second semiconductor chip) on a surface (active surface) of a parent chip M (first semiconductor chip).
Semiconductor chip) is bonded in a face-down state with its surface (active surface) facing the chip. Each of the parent chip M and the child chip D is formed of, for example, a silicon chip, and has an active element such as a transistor, a passive element such as a resistor or a capacitor, and a wiring formed on each surface.

In this embodiment, the parent chip M and the child chip D are both formed in a rectangular shape in plan view, and the child chip D is formed to be slightly smaller than the parent chip M in plan view. ing. In the area around the child chip D, a plurality of protruding electrodes (in this embodiment, columnar electrodes) T as external connection electrodes are formed on the surface (active surface) of the parent chip M. A region of the surface of the parent chip M where the child chip D or the protruding electrode T is not formed is resin-sealed with a protective resin (for example, epoxy resin) 11 to protect the surface of the parent chip M. . The surface of the child chip D is opposed to the parent chip M, and is protected from the outside by sealing the side surface with the protective resin 11.

In this embodiment, the protective resin 11, the head of the protruding electrode T, and the non-active surface of the daughter chip D are flush with each other. The semiconductor device 10 having such a configuration can be made extremely thin having a height close to the sum of the respective thicknesses of the parent chip M and the child chip D.
An on-chip semiconductor device can be realized. FIG. 2 is a cross-sectional view showing the steps of manufacturing the semiconductor device 10 as described above in the order of steps. A protective film (passivation film) made of a nitride film or the like is formed on a surface (active surface) Wa of a semiconductor wafer W (hereinafter, simply referred to as “wafer W”) as a semiconductor substrate. At a plurality of locations that need to be connected to the outside, the pads of the internal wiring are exposed. Fig. 2 (a)
As shown in FIG.
Is formed (electrode forming step). The protruding electrode T is formed on a pad for external connection, and the bump B is formed on a pad for inter-chip connection to be connected to the child chip D. Both the protruding electrode T and the bump B can be formed of the same material, and for example, are preferably formed of an oxidation-resistant metal such as gold. Further, the bump electrode T is connected to the bump B
It is preferably formed higher than the above.

Subsequently, as shown in FIG. 2B, the child chip D is replaced with its surface (active surface) Da by the surface Wa of the wafer W.
After bonding face down (chip bonding step), the surface Wa of the wafer W, the protruding electrodes T, and the bumps B are resin-sealed with the protective resin 11 (resin sealing step). At this time, the head of the protruding electrode T and / or the back surface (inactive surface) Db of the child chip D may be exposed from the protective resin 11, and the exposed portion of the front surface Wa of the wafer W is covered with the protective resin 11. It only needs to be covered.

Subsequently, as shown in FIG.
Back surface (inactive surface) Wb is polished or ground using a grinder to further reduce the thickness. Next, the protruding electrodes T are exposed as shown in FIG. 2D by polishing or grinding the protective resin 11 using a grinder (electrode exposing step). In addition, the grinding position is child chip D
Is reached, the protective resin 11 and the non-active surface Db of the secondary chip D are simultaneously polished or ground (chip grinding step), and the secondary chip D and the protective resin 11 are removed.
Is further reduced in thickness.

Thereafter, as shown in FIG. 2E, the wafer W is cut along with the protective resin 11 by a dicing saw 15 along a scribe line L (cutting line), so that the parent chip cut out from the wafer W is cut. An individual piece of the semiconductor device 10 having the structure shown in FIG. In addition, any of the step of FIG. 2C and the step of FIG. 2D may be performed first, and if unnecessary, the step of FIG. 2C may be omitted. .

As described above, according to the method of this embodiment, before cutting out the parent chip M from the wafer W,
And a protruding electrode T as an external connection electrode is formed on the front surface Wa side of the wafer W to which the child chip D is bonded. And the protective resin 1
By cutting out the wafer W whose front surface Wa is protected in step 1, a semiconductor chip 10 having a packaged chip-on-chip structure can be obtained. Therefore, a thin chip-on-chip type semiconductor device can be efficiently produced.

Although one embodiment of the present invention has been described, the present invention can be embodied in other forms.
For example, in the above-described embodiment, the protective resin 11, the protruding electrode T, and the non-active surface Db of the child chip D are flush with each other. However, as shown in FIG. It may be protruded from the surface of the resin 11 or as shown in FIG.
As shown in (2), the inactive surface Db side of the child chip D may protrude from the surface of the protective resin 11. FIG. 3 or FIG.
Can be manufactured by forming the protective resin 11 to be sufficiently thin, for example. In this case, the projection electrode T
If there is a possibility that the protective resin 11 adheres to the head of the projection electrode T, the protective resin adhered to the head of the protruding electrode T may be removed by polishing, grinding, or etching with a grinder or the like.

Further, in the above embodiment, the example in which the protruding electrode T is formed higher than the non-active surface Db of the sub chip D has been described. However, as shown in FIG. It may be lower than the non-active surface Db of the child chip D (for example, less than 100 μm). Even in this case, after both the back grinding (grinding to the position indicated by the solid line) and the surface grinding (grinding to the position indicated by the two-dot chain line), the above-mentioned first grinding is performed.
A structure similar to that of the embodiment can be obtained. By reducing the height of the projecting electrode T, the projecting electrode T can be easily formed in a short time, and the material can be reduced, so that productivity can be improved, and
It can contribute to cost reduction. However, in order to simultaneously grind the daughter chip D and the protruding electrode T to make their surfaces flush, the height of the protruding electrode T formed first is higher than the active surface Da of the daughter chip D. It is preferable to keep it high.

In the above embodiment, an example in which one child chip D is joined to one parent chip M has been described. However, even if two or more child chips D are joined to one parent chip M, Good. Further, in the above-described embodiment, the protruding electrodes T are columnar, but may be bump-shaped. Further, in the above-described embodiment, the parent chip M and the child chip D are both made of a silicon semiconductor. However, besides silicon, any other semiconductor such as a gallium arsenide semiconductor or a germanium semiconductor may be used. A semiconductor chip using a material can be applied to the semiconductor device of the present invention. In this case, the semiconductor materials of the parent chip M and the child chip D may be the same or different.

In addition, various design changes can be made within the scope of the matters described in the claims.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a method for manufacturing the semiconductor device in the order of steps.

FIG. 3 is a cross-sectional view illustrating a configuration of a semiconductor device according to another embodiment of the present invention.

FIG. 4 is a sectional view showing a configuration of a semiconductor device according to still another embodiment of the present invention.

FIG. 5 is a cross-sectional view for explaining a manufacturing step of a semiconductor device according to still another embodiment of the present invention.

FIG. 6 is an illustrative view for explaining a structure of a conventional chip-on-chip type semiconductor device;

[Explanation of symbols]

 Reference Signs List 10 semiconductor device 11 protective resin M parent chip D child chip T projecting electrode B bump W semiconductor wafer L scribe line

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Claims (4)

[Claims] A first semiconductor chip; a second semiconductor chip bonded to a surface of the first semiconductor chip; and a second semiconductor chip formed on a surface of the first semiconductor chip for connection to the outside. A semiconductor device comprising: a protruding electrode; and a protective resin for sealing a surface of the first semiconductor chip with a head of the protruding electrode exposed. 2. A chip bonding step of bonding a plurality of semiconductor chips on a surface of a semiconductor substrate in a face-down state with their active surfaces facing the surface of the semiconductor substrate; An electrode forming step of forming a projecting electrode; and a resin sealing step of sealing a surface of the semiconductor substrate exposed after the formation of the semiconductor chip and the projecting electrode with a protective resin while exposing a head of the projecting electrode. A method for manufacturing a semiconductor device, comprising: a stopping step; and a cutting step of cutting out the semiconductor device having a chip-on-chip structure by cutting the semiconductor substrate along a predetermined cutting line. 3. The semiconductor device according to claim 2, wherein said resin sealing step includes an electrode exposing step of exposing a head portion of said protruding electrode by removing a surface layer portion of said protective resin. Production method. 4. The method of manufacturing a semiconductor device according to claim 3, wherein said electrode exposing step includes a chip grinding step of simultaneously polishing or grinding said protective resin and an inactive surface side of said semiconductor chip. .