JP2001094038A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize satisfactory conveyance with vacuum suction hands, independently of the joining position of a subordinate chip to a master chip and the size of the subordinate chip. SOLUTION: On a surface 11 of a master chip 1, a dummy chip 3 unrelated to the function which this semiconductor device has is jointed to a region, except the jointing region of a subordinate chip 2. A semiconductor module constituted by jointing the subordinate chip 2 and the dummy chip 3 to the master chip 1 can be carried, by sucking the rear 22 of the subordinate chip 2 and the rear 33 of the dummy chip 3 with vacuum suction hands H1 and H2, respectively.

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 a child chip is superimposed on and joined to the surface of a parent chip.

[0002]

2. Description of the Related Art Conventionally, there has been known a semiconductor device having a chip-on-chip structure in which a child chip is superposed and joined to a surface of a parent chip. In such a semiconductor device having a chip-on-chip structure, for example, a plurality of bumps are formed on the surface of a child chip so as to protrude, and the plurality of bumps are formed on the surface of a parent chip by exposing them. By bonding to the pad, the child chip is supported on the parent chip, and electrical connection between the semiconductor chips is achieved.

[0003] After a semiconductor module is constructed by bonding a child chip to a parent chip, the semiconductor module is immediately mounted on a lead frame, or when mounted on a chip tray and then mounted on a lead frame. There are cases. In any case, the semiconductor module is conveyed while sucking the back surface of the child chip bonded to the parent chip with a vacuum suction hand.

[0004]

The bonding position of the child chip on the surface of the parent chip is not always set at the center of the parent chip. That is, as shown in FIG. 4, the bonding position of the child chip 92 may be set at an uneven position on the surface of the parent chip 91. In such a case, if the back surface of the child chip 92 is sucked and transported by the vacuum suction hand H, the balance is poor, so that the parent chip 91 and the child chip 92 are dropped during the transportation, or the parent chip 91 is There is a possibility that it will be peeled off and fall off.

[0005] The size of the child chip joined to the parent chip also varies, and the size of the child chip 94 joined to the parent chip 93 may be very small as shown in FIG. If the size of the child chip 94 is small in this way, the back surface of the child chip 94 cannot be suctioned by the vacuum suction hand H, and the parent chip 93 and the child chip 94 cannot be transported. If the back surface of the parent chip is suctioned and transported by a vacuum suction hand or the like, the parent chip and the child chip can be satisfactorily transported regardless of the bonding position of the child chip to the parent chip and the size of the child chip. However, if the back surface of the parent chip is sucked, it becomes difficult to mount the parent chip and the child chip on the lead frame. Therefore, this method is not preferable. Also, it is not preferable that the surface of the parent chip is sucked by the vacuum suction hand because the surface of the parent chip may be damaged.

An object of the present invention is to provide a semiconductor device which can be satisfactorily conveyed by a vacuum suction hand irrespective of a bonding position of a child chip to a parent chip and a size of the child chip.

[0007]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention, there is provided a parent chip having a functional element formed on a surface on an active surface layer side;
In a state where the surface on the active surface layer region side on which the functional element is formed faces the surface of the parent chip, the child chip joined to the parent chip and the child chip are joined on the surface of the parent chip. And a dummy chip that is bonded to a non-existent region and does not contribute to an electrical function of the semiconductor device.

According to the present invention, on the surface of the parent chip,
A dummy chip other than the child chip is bonded, and the semiconductor module configured by bonding the child chip and the dummy chip to the parent chip has a back surface of the child chip and a back surface of the dummy chip (the side opposite to the surface facing the parent chip). Can be conveyed while being suctioned by separate vacuum suction hands. Thereby, even if the child chip is bonded to the surface of the parent chip at an uneven position, the semiconductor module can be held and transported in a well-balanced manner. therefore,
There is no possibility that the semiconductor module will fall from the vacuum suction hand or the parent chip will peel off during the transportation.

It is preferable that the distance between the dummy chip and the surface of the parent chip is set substantially equal to the distance between the surface of the child chip and the surface of the parent chip. Further, it is preferable that the thickness of the dummy chip is set substantially equal to the thickness of the sub chip. By doing so, if the front surface of the parent chip is almost flush, the back surface of the dummy chip and the back surface of the child chip can be made almost the same height, and the back surface of the child chip and The back surface of the dummy chip can be sucked well. In other words, so that the back surface of the dummy chip and the back surface of the child chip are approximately the same height,
It is preferable that the dimensions and the bonding mode of the dummy chip are determined.

It is preferable that the dummy chip is disposed on the surface of the parent chip at a position substantially symmetrical with the child chip with respect to the center of the parent chip. Further, when a plurality of the dummy chips are provided, the dummy chips are bonded on the surface of the parent chip such that the child chips and the dummy chips are substantially uniformly dispersed. Is preferred. This allows the semiconductor module to be transported while being held in a more balanced manner.

Further, when the size of the child chip is small and the back surface of the child chip cannot be sucked and held by the vacuum suction hand, it is preferable that a plurality of the dummy chips are provided. In this case, it is preferable that the back surfaces of the plurality of dummy chips are suctioned by different vacuum suction hands, respectively, and the semiconductor module is transported. In this case, the plurality of dummy chips are preferably joined at positions symmetrical with respect to the center of the parent chip on the surface of the parent chip, and three or more dummy chips are provided. In that case, the dummy chip
It is preferable that the chips are joined so as to be distributed almost uniformly on the surface of the parent chip. This allows the semiconductor module to be transported while being held in a more balanced manner.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an illustrative sectional view showing a schematic configuration of a semiconductor device according to an embodiment of the present invention. This semiconductor device has a so-called chip-on-chip structure in which a child chip 2 is overlapped and joined to a surface 11 of a parent chip 1. Parent chip 1
And child chip 2 are made of, for example, a silicon chip. The surface 11 of the parent chip 1 is a surface on the active surface layer region side on which a functional element such as a transistor is formed on a semiconductor substrate forming a base of the parent chip 1, and the outermost surface is a surface protection film made of, for example, silicon nitride. Covered with. A bonding region of the child chip 2 is set at a position deviated on the surface protective film, and a plurality of chip connection pads (not shown) for connection with the child chip 2 are provided in this bonding region. It is formed to be exposed. A plurality of pads 12 for external connection are provided near the periphery on the surface protection film.
Are exposed.

The child chip 2 is joined to the parent chip 1 by a so-called face-down method in which the surface 21 of the child chip faces the surface 11 of the parent chip 1. Child chip 2
Surface 21 is a surface on the active surface layer region side on which a functional element such as a transistor is formed on a semiconductor substrate serving as a base of the sub-chip 2, and the outermost surface is covered with a surface protective film made of, for example, silicon nitride. . On the surface protective film, bumps B are formed at positions facing the chip connection pads of the parent chip 1 respectively. The bump B is made of an oxidation-resistant metal material such as gold, platinum, silver, palladium or iridium. The child chip 2 is supported while maintaining a predetermined distance from the front surface 11 of the parent chip 1 by connecting the bumps B to the chip connection pads of the parent chip 1 facing each other. 1 and is electrically connected.

On the surface 11 of the parent chip 1, the child chip 2
A dummy chip 3 irrelevant to the function of the semiconductor device is bonded to a region other than the bonding region. On the surface 31 of the dummy chip 3 facing the parent chip 1,
For example, a plurality of bumps 3 made of an oxidation-resistant metal material such as gold, platinum, silver, palladium or iridium.
The dummy chip 3 is supported at a predetermined interval from the surface 11 of the parent chip 1 by bonding the bump 32 to a surface protection film covering the surface 11 of the parent chip 1. That is, the dummy chip 3 is not electrically connected to either the parent chip 1 or the child chip 2.

The semiconductor module formed by bonding the child chip 2 and the dummy chip 3 to the parent chip 1 is mounted (die-bonded) on the island 41 of the lead frame, and the external connection pads 12 of the parent chip 1 are bonded. The lead terminal 42 of the lead frame with the wire 5
After that, it is set in a mold cavity (not shown), and is sealed in the package 6 by performing a resin sealing step. FIG. 2 is a diagram for explaining a method of transporting a semiconductor module configured by bonding a child chip 2 and a dummy chip 3 to a parent chip 1. A semiconductor module configured by bonding the child chip 2 and the dummy chip 3 to the parent chip 1 is connected to a chip tray (not shown) for temporarily storing a lead frame or a semiconductor module by two vacuum suction hands H1 and H2. ).

The vacuum suction hands H1 and H2 are shown with suction holes (not shown) formed in the front end surface (lower end surface) respectively joined to the back surface 22 of the child chip 2 and the back surface 33 of the dummy chip 3. By performing vacuum suction using a vacuum source that is not used, the semiconductor module including the parent chip 1, the child chip 2, and the dummy chip 3 can be suction-held. By moving the semiconductor module while holding it, the semiconductor module can be transported toward the lead frame or the chip tray.

As described above, according to this embodiment, the dummy chip 3 is bonded to the front surface 11 of the parent chip 1 in addition to the child chip 2.
Is bonded to the parent chip 1 and the back surface 22 of the child chip 2 and the back surface 33 of the dummy chip 3 are conveyed while being suctioned by the vacuum suction hands H1 and H2. Thus, even when the child chip 2 is bonded to the surface 11 of the parent chip 1 at a biased position, the semiconductor module can be held and transported in a well-balanced manner. There is no risk that the module will fall or the parent chip 1 will peel off.

In order to transport the semiconductor module in a well-balanced manner by the vacuum suction hands H1 and H2,
It is preferable that the dummy chip 3 is joined at a position that is substantially symmetrical with the joining position of the child chip 2 with respect to the center of the parent chip 1. Further, the distance between the surface 31 of the dummy chip 3 and the surface 11 of the parent chip 1 is preferably set substantially equal to the distance between the surface 21 of the child chip 2 and the surface 11 of the parent chip 1. . Further, it is preferable that the thickness of the dummy chip 3 (the thickness in the direction orthogonal to the surface 31) is set to be substantially equal to the thickness of the child chip 2. By doing so, the back surface 33 of the dummy chip 3 and the back surface 22 of the child chip 2 can be made substantially the same height, and the two vacuum suction hands H1 and H2 can be respectively moved to the back surface 22 of the child chip 2 and the dummy chip 3 can be successfully adsorbed to the back surface 33.

Further, the dummy chip 3 can be formed of, for example, a silicon chip, and a functional element such as a transistor may be formed therein, or a functional element may not be formed therein. For example, the dummy chip 3 may have the same configuration as the child chip 2. In this case, the dummy chip 3 is provided separately from the child chip 2.
And the size and weight of the child chip 2 and the dummy chip 3 can be made substantially the same. Therefore, the semiconductor modules can be held and transported in a more balanced manner by the vacuum suction hands H1 and H2.

FIG. 3 is a diagram for explaining another embodiment of the present invention. 3, parts corresponding to the respective parts shown in FIG. 2 described above are denoted by the same reference numerals as in FIG. In this embodiment, a configuration in the case where the size of the child chip 2 bonded to the parent chip 1 is small enough to prevent suction by the vacuum suction hands H1 and H2 is taken as an example. That is, for example, two dummy chips 3A and 3B are joined to the surface 11 of the parent chip 1, and the child chip 2 and the dummy chip 3 are attached to the parent chip 1.
The semiconductor modules formed by joining A and 3B are dummy chips 3A and 3A by vacuum suction hands H1 and H2, respectively.
The back surface of 3B is conveyed by suction. Therefore, even if the size of the child chip 2 is small, the semiconductor module can be transported favorably.

In this embodiment, the dummy chip 3
A and 3B are preferably joined at positions substantially symmetric with respect to the center of the parent chip 1, so that the vacuum suction hands H1 and H2 can hold and transport the semiconductor module in a more balanced manner. it can. Further, it is preferable that the dummy chips 3A and 3B have the same configuration. In such a case, the back surface of the dummy chip 3A and the back surface of the child chip 2 can be made substantially the same height, and the two vacuum suction hands H1 and H2 can be suctioned to the back surfaces of the dummy chips 3A and 3B, respectively. And a better transport can be realized.

Although two embodiments of the present invention have been described, the present invention can be implemented in other embodiments. For example, in the above-described first embodiment, one dummy chip is bonded to the parent chip.
A plurality of dummy chips may be joined to the parent chip 1. In this case, it is preferable that the bonding positions of the plurality of dummy chips are determined so that the child chips and the plurality of dummy chips are bonded in a uniformly dispersed state on the surface of the parent chip. By doing so, the child chip and the plurality of dummy chips can be suctioned by separate vacuum suction hands and conveyed in a well-balanced manner.

In the above-described second embodiment,
Three or more dummy chips may be joined to the surface of the parent chip. In this case, it is preferable that the bonding positions of the dummy chips are determined so that the dummy chips are bonded in a uniformly dispersed state on the surface of the parent chip. By doing so, a plurality of dummy chips can be suctioned by separate vacuum suction hands and transported in a well-balanced manner. Furthermore, the present invention is not limited to the above embodiments. For example, the parent chip and the child chip are both chips made of silicon. However, in addition to silicon, any other semiconductor material such as a compound semiconductor (for example, a gallium arsenide semiconductor) or a germanium semiconductor is used. It may be a semiconductor chip. In this case, the semiconductor material of the parent chip and the semiconductor material of the child chip 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 an illustrative sectional view showing a schematic configuration of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of transporting a semiconductor module provided in the semiconductor device.

FIG. 3 is a diagram for explaining another embodiment of the present invention.

FIG. 4 is a diagram for describing inconvenience when a bonding position of a child chip to a parent chip is deviated;

FIG. 5 is a diagram for describing inconvenience when the size of a child chip is small.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Parent chip 11 Surface of parent chip 2 Child chip 21 Surface of child chip 22 Back of child chip 3, 3A, 3B Dummy chip 33 Back of dummy chip H1, H2 Vacuum suction hand

Claims (1)

[Claims] A first chip having a functional element formed on a surface on an active surface layer side; and a parent chip having a surface on the active surface layer side on which a functional element is formed facing the surface of the parent chip. A child chip joined to the parent chip, and a dummy chip joined to a region of the surface of the parent chip where the child chip is not joined and not contributing to an electrical function of the semiconductor device. Semiconductor device.