JP4606783B2 - Semiconductor device - Google Patents

Description

The present invention relates to a semiconductor device using an interposer that electrically connects a semiconductor element (chip) and a semiconductor package .

  With the development of information society, semiconductor devices are required to increase processing speed. In order to meet such demands, flip chip type semiconductor devices have been developed in which the length of the wiring in the semiconductor device is reduced and the inductance component is reduced.

  As shown in FIG. 1, the flip-chip type semiconductor device includes a semiconductor element 1, a semiconductor package 10 in the form of a wiring board, and pads corresponding to the surface on which the semiconductor element of the semiconductor package 10 is mounted. Underfill for filling a gap between the semiconductor element 1 and the semiconductor package 10 and a metal bump 2 such as solder (hereinafter also referred to as “internal connection terminal” for convenience) for electrically connecting the electrodes of the semiconductor element 1. Resin 8 and external connection terminals 11 such as solder bumps which are provided on the surface of the semiconductor package 10 opposite to the side on which the semiconductor element 1 is mounted and electrically connect the device 30 to a mounting substrate such as a mother board It has.

  In the semiconductor device 30 as shown in FIG. 1, when a temperature change occurs in the semiconductor device 30, the semiconductor element 1 and the semiconductor package 10 are in-plane due to different thermal expansion coefficients of the semiconductor element 1 and the semiconductor package 10. It expands or contracts at different degrees in the direction, heat distortion occurs between the semiconductor element 1 and the semiconductor package 10, and the positions of the electrodes of the semiconductor element 1 and the pads of the semiconductor package 10 change relatively. At this time, there is a problem that the internal connection terminal 2 fixed to both of them is deformed or cracked in some cases, and the reliability of the semiconductor device 30 is lowered.

  In order to cope with such a problem, a semiconductor device as shown in FIG. 2A has been proposed as another conventional example (see, for example, Patent Document 1 and Patent Document 2).

  In this semiconductor device 40, an interposer 5 in which a conductor pillar 7 is embedded in a position corresponding to the electrode of the semiconductor element 1 of the elastic sheet 6 is interposed between the semiconductor element 1 and the semiconductor package 10, The electrodes of the semiconductor element 1 are electrically connected to the pads of the semiconductor package 10 through the internal connection terminals 2 and 3 connected to both ends of the conductor pillar 7.

  In the semiconductor device 40 as shown in FIG. 2A, when a temperature change occurs, thermal distortion occurs between the semiconductor element 1 and the semiconductor package 10 as in the semiconductor device shown in FIG. Since the interposer 5 absorbs the displacement due to the strain by expanding and contracting, the internal connection terminal 2 is less likely to be deformed or cracked. However, in this case, the internal connection terminal 2 is integrated with the conductor pillar 7 without being deformed, and in the vicinity of the junction between the electrode of the semiconductor element 1 to which the internal connection terminal 2 is fixed and the internal connection terminal 2 (hereinafter, For convenience, it is referred to as “base portion of the internal connection terminal 2”), and the moment between the internal connection terminal 2 and the conductor column 7 is increased. At this time, as shown in FIG. 2B in which the portion A in FIG. 2A is enlarged, the interlayer insulating film 21 and the wiring layer 22 inside the semiconductor element 1 located in the vicinity of the base portion of the internal connection terminal 2. Stress due to the moment is applied to it, and these are damaged.

The interlayer insulating film 21 is generally made of silicon oxide (SiO ₂ ) or the like, but in order to further increase the processing speed in the future, the interlayer insulating film 21 should be replaced with a so-called Low-k material (low dielectric constant material). Is fully expected. However, since the low-k material is generally a material having a lower strength (weaker) than silicon oxide, the above-described problem of damage due to thermal strain appears more remarkably.
WO96 / 09645 publication Japanese Patent Laid-Open No. 10-22351

The present invention was created in view of the above-mentioned problems in the prior art, and in a semiconductor device using an interposer , damage to an interlayer insulating film, a wiring layer, and the like inside a semiconductor element due to thermal strain is suppressed, and thus the semiconductor device The purpose is to contribute to the improvement of reliability.

In order to solve the above-described problems of the prior art, according to one aspect of the present invention, a semiconductor element, a semiconductor package, and an interposer interposed between the semiconductor element and the semiconductor package, and having elasticity A plate-like insulator, a plurality of conductors embedded in the thickness direction of the plate-like insulator, and a surface of the plate-like insulator on the side on which the semiconductor element is mounted; An interposer having a first sheet-like member having a similar thermal expansion coefficient, wherein the semiconductor element and the semiconductor package are electrically connected via the plurality of conductors, and the semiconductor A semiconductor device is provided in which an element is connected to one end of the conductor through a first internal connection terminal .

Further, in the semiconductor device, the interposer, the plate-like the insulator to the side for mounting the semiconductor element provided on a surface opposite to a second sheet having a thermal expansion coefficient comparable to the semiconductor package You may have a member further.

According to the configuration of the semiconductor device according to one aspect of the present invention , in the interposer interposed between the semiconductor element and the semiconductor package, the semiconductor element is mounted on the surface of the plate-like insulator on the side on which the semiconductor element is mounted. A first sheet-like member having a similar thermal expansion coefficient is provided. Therefore, when a temperature change occurs in this semiconductor device, there is almost no difference in thermal expansion coefficient between the semiconductor element and the first sheet-like member, so that the semiconductor element and the first sheet-like member face each other. It expands or contracts uniformly in the direction parallel to the plane of the film, and there is almost no thermal strain between them. Therefore, each of the conductors embedded through the thickness direction of the plate-like insulator, the one end of the conductor moves the surface of the semiconductor device side connected via the first internal connection terminals as a fulcrum Therefore, a large moment or shearing force is hardly generated on the surface of the semiconductor element, and the conductor on the plate-like insulator side from the first sheet-like member forms the interface between the first sheet-like member and the plate-like insulator. It will move as a fulcrum. Thereby, the stress applied to the semiconductor element is relaxed, and the interlayer insulating film and the wiring layer inside the semiconductor element are hardly damaged, so that the reliability of the semiconductor device can be improved.

In the semiconductor device according to the above aspect, a second sheet-like member having a thermal expansion coefficient comparable to that of the semiconductor package is provided on the surface of the interposer plate-like insulator opposite to the side on which the semiconductor element is mounted. When provided, the second sheet-like member and the semiconductor package are uniformly expanded or contracted in the direction parallel to the opposing surfaces, so that almost no thermal distortion occurs between them. Therefore, each conductor embedded penetrating in the thickness direction of the plate-like insulator does not move with the surface of the semiconductor package on the side to which the other end is connected as a fulcrum. The conductor on the plate-like insulator side moves with the interface between the second sheet-like member and the plate-like insulator as a fulcrum. Thereby, the stress applied to the semiconductor package is also alleviated and the multilayer structure inside the semiconductor package is hardly damaged, so that the reliability of the semiconductor device can be further improved.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 3 is a cross-sectional view showing a configuration of an interposer and a semiconductor device using the interposer according to an embodiment of the present invention.

The semiconductor device 50 according to the present embodiment includes, for example, a semiconductor element 51 having a multilayer structure as shown in FIG. 2B, a semiconductor package 60 having the form of a wiring board, and the semiconductor element 51 and the semiconductor package 60. An interposer 55 interposed therebetween, internal connection terminals 52 and 53 such as solder bumps for electrically connecting between the semiconductor element 51 and the interposer 55, and between the interposer 55 and the semiconductor package 60, and the semiconductor element between 51 and interposer 55, and the underfill resin 58 and 59 which are filled respectively between the interposer 55 and the semiconductor package 60, the semiconductor package 60, on the surface opposite to the side where the interposer 55 is mounted The device 50 is electrically connected to a mounting board such as a mother board. And an external connection terminal 61 such as solder balls.

The interposer 55 includes an insulating elastic sheet 56 (plate-like insulator) and a rigid sheet 70 (first sheet-like member) provided on the surface of the elastic sheet 56 on which the semiconductor element 51 is mounted. The elastic sheet 56 has a plurality of conductor columns 57 that are embedded in the thickness direction at portions corresponding to the electrodes of the semiconductor element 51 . The elastic sheet 56 is an epoxy resin, a polymer material such as polyimide resin. The rigid sheet 70 has a thermal expansion coefficient comparable to that of the semiconductor element 51 . For example, when the main material constituting the semiconductor element 51 is silicon (Si), the rigid sheet 70 is made of Si, glass, ceramics, 36 alloy (Fe (iron) -36 wt% Ni (nickel)), It consists of materials, such as 42 alloy (Fe-42 weight% Ni). The interposer 55 is formed, for example, by forming a through hole in the elastic sheet 56 by laser irradiation and embedding copper (Cu) or tin copper (SnCu) in the through hole using a plating method to form the conductor column 57 . by bonding the rigid sheet 70 having a through-hole of the degree of diameter not to correspond to the arrangement of the conductor posts 57 contact the conductor columns 57 on one surface of the elastic sheet 56 can be obtained.

  The semiconductor device 50 shown in FIG. 3 can be manufactured as follows when the internal connection terminals 52 and 53 are solder bumps and the external connection terminal 61 is a solder ball.

  First, an interposer 55 is sandwiched between the semiconductor element 51 provided with the internal connection terminal 52 and the semiconductor package 60 provided with the internal connection terminal 53, and heat treatment is performed in a reflow furnace, whereby the semiconductor element 51, the interposer 55, and the semiconductor package 60. Join. Next, the underfill resins 58 and 59 are filled in the gap between the semiconductor element 51 and the interposer 55 and the gap between the interposer 55 and the semiconductor package 60, and heat treatment is performed in a constant temperature furnace. Is cured. Finally, the external connection terminal 61 is arranged at a predetermined position on the surface of the semiconductor package 60 opposite to the side on which the semiconductor element is mounted, and heat treatment is performed again in a reflow furnace, so that the semiconductor package 60 and the external connection terminal By bonding 61, the semiconductor device 50 can be obtained.

  Further, the internal connection terminal 52 is not limited to a solder bump, but can be replaced by, for example, a protrusion formed by growing Cu by a plating method and a stud bump made of gold (Au) formed by using a wire bonding method. It is. In these cases, the semiconductor device 50 can be obtained through the same manufacturing process as that described above by applying paste-like solder or resin containing conductive particles to the internal connection terminals 52 and 53.

  According to the configuration of the interposer 55 according to the present embodiment, the rigid sheet 70 having the same thermal expansion coefficient as that of the semiconductor element 51 is provided on the surface of the interposer 55 on the side where the semiconductor element 51 is mounted. In the semiconductor device 50 using the interposer 55, when a temperature change occurs in the semiconductor device 50, the thermal expansion coefficient between the rigid sheet 70 and the semiconductor package 60 has a certain degree of difference. Although distortion occurs, there is almost no difference in the coefficient of thermal expansion between the semiconductor element 51 and the rigid sheet 70. Therefore, thermal expansion is almost generated between the semiconductor element 51 and the rigid sheet 70 because the semiconductor element 51 is uniformly expanded or contracted in the in-plane direction. Absent. Therefore, the internal connection terminal 52 and the conductor column 57 are integrated and do not move with the base portion of the internal connection terminal 52 as a fulcrum, and the conductor column 57 below the rigid sheet 70 is the interface between the rigid sheet 70 and the elastic sheet 56. Will move as a fulcrum. Thereby, the stress applied to the semiconductor element 51 is relaxed, and the interlayer insulating film and the wiring layer inside the semiconductor element 51 are hardly damaged, so that the reliability of the semiconductor device 50 can be improved.

  In order to confirm the above-described effect, the present inventor analyzed the stress generated in the semiconductor device by simulation.

  In this simulation, ABAQUS6.31 was used as simulation software. In order to compare the difference in internal stress between the semiconductor device 50 according to the present embodiment (FIG. 3) and the semiconductor device 40 according to the conventional example (FIG. 2), a simulation model (hereinafter referred to as a simulation model) is used for each of these two semiconductor devices. Simply called "model"). In each model, the material of the internal connection terminals was Cu, the material of the conductor pillars was SnCu, the material of the core portion of the semiconductor package was 36 alloy, and the material of the elastic sheet was epoxy resin. In the model of the semiconductor device 50 according to the present embodiment, the rigid sheet is Si. With respect to these two models, the internal stress was analyzed when the temperature at which no internal stress was generated was 180 ° C., which is the cure temperature of the underfill resin, and the temperature was 25 ° C., which is normal temperature.

4A and 4B are cross-sectional views showing simulation results, in which FIG. 4A shows a simulation result based on the model of the semiconductor device according to the present embodiment, and FIG. 4B shows a simulation result based on the model of the semiconductor device according to the conventional example. ing. Here, reference numerals corresponding to the respective parts shown in FIGS. 3 and 2 are given to the respective parts shown in FIGS. 4 (a) and 4 (b).

  In the conventional example (see FIG. 4B), the internal connection terminal 2 and the conductor pillar 7 are surfaces on the side facing the semiconductor package 60 of the semiconductor element 1 (hereinafter referred to as “main surface of the semiconductor element 1” for convenience). The angle from the vertical direction is followed to the displacement due to thermal strain. On the other hand, in the present invention (see FIG. 4A), the conductor pillar 57 on the semiconductor package 70 side of the rigid sheet 70 follows the displacement due to thermal strain. The partial conductor pillars 57 and the internal connection terminals 52 are held in a state of being fixed perpendicular to the main surface of the semiconductor element 51 and hardly follow displacement due to thermal strain. From these results, in the semiconductor device according to the conventional example, the conductor pillar 7 and the internal connection terminal 2 are substantially integrated and move with the base portion of the internal connection terminal 2 as a fulcrum. In the semiconductor device according to the present embodiment, the conductor pillar 57 and It was confirmed that the internal connection terminal 52 does not move as a unit, and the conductor column 57 in the portion closer to the semiconductor package 70 than the rigid sheet 70 moves using the vicinity of the interface between the rigid sheet 70 and the elastic sheet 56 as a fulcrum.

  In order to clarify the difference between the simulation results of these two models, the stress applied from the interposer to the internal connection terminal and the semiconductor element was analyzed for each model. FIG. 5 shows the result of the analysis. The result of the stress analysis of the model of the semiconductor device according to this embodiment is shown on the right side, and the result of the stress analysis of the model of the semiconductor device according to the conventional example is shown on the left side. Yes.

  According to the results of these stress analyses, the equivalent stress applied to the internal connection terminal from the package side is reduced by about 87% in the model of the semiconductor device according to the present embodiment compared to the model of the semiconductor device according to the conventional example. In addition, it was confirmed that the maximum stress applied to the semiconductor element was reduced by about 63%. That is, it was confirmed that most of the stress applied to the semiconductor element from the outside is removed by the interposer.

  As described above, the simulation clearly shows that the stress applied to the internal connection terminals and the semiconductor element is significantly reduced in the semiconductor device using the interposer according to the present embodiment as compared with the semiconductor device using the interposer according to the conventional example. became. If at least the thermal expansion coefficient of the rigid sheet is closer to the thermal expansion coefficient of the semiconductor element than the elastic sheet, the stress can be reduced to some extent as compared with the conventional semiconductor device.

  6 to 8 show various modifications of the interposer and the semiconductor device (FIG. 3) according to the above-described embodiment.

  FIG. 6 shows the configuration of an interposer according to a first modification of the above-described embodiment and a semiconductor device using the same in the form of a cross-sectional view.

  Compared with the semiconductor device 50 shown in FIG. 3, the semiconductor device 50 a of this modification is formed by stacking a plurality of insulating resin films 56 a on the interposer 55 a, and each resin film has a thickness direction of 56 a. Are different in that one conductor pillar 57a is formed by stacking conductor pillars formed so as to penetrate through the conductor pillars. Similar to the interposer 55 shown in FIG. 3, the interposer 55a can be obtained by forming a conductive column at the same position of each elastic film or sheet 56a, and superposing the elastic films 56a and thermocompression bonding. It will be understood that the semiconductor device 50a of this modification also has the same effect as the semiconductor device 50 shown in FIG.

  FIG. 7 is a cross-sectional view showing the configuration of an interposer according to a second modification and a semiconductor device using the interposer.

  The semiconductor device 50b according to the present modification is the same as the semiconductor device 50a according to the first modification in that the interposer 55b is formed by laminating a plurality of insulating elastic films 56b. The difference is that a wiring layer 57b for adjusting a shift between the arrangement of the electrode pads of the semiconductor element 51 and the arrangement of the electrode pads of the semiconductor package 60 is provided instead of the pillar 57a. This interposer 55b forms conductor columns and conductor patterns that electrically connect the conductor columns when they are incorporated in the interposer 55b at desired positions of the respective elastic films 56b, and overlaps the elastic films 56b. It can be obtained by thermocompression bonding. It will be understood that the semiconductor device 50b of this modification also has the same effect as the semiconductor device 50 shown in FIG.

  FIG. 8 shows the configuration of an interposer according to a third modification and a semiconductor device using the interposer in the form of a cross-sectional view.

  The semiconductor device 50c of this modification is different from the semiconductor device 50 shown in FIG. 3 in that a rigid sheet 71 is provided on the surface of the interposer 55c opposite to the side on which the semiconductor element 51 is mounted. In this case, a material having a thermal expansion coefficient comparable to that of the semiconductor package 60 is selected as the material of the rigid sheet 71. For example, when the core material of the semiconductor package 60 is 42 alloy (Fe-42 wt% Ni), the material of the rigid sheet 71 may be 42 alloy similarly to the core material. Another example of the core material of the semiconductor package is 36 alloy (Fe-36 wt% Ni).

  In this way, thermal distortion hardly occurs not only between the semiconductor element 51 and the rigid sheet 70 but also between the rigid sheet 71 and the semiconductor package 60. That is, the internal connection terminals 52 and 53 and the conductor column 57 are integrated to move using the base portion of the internal connection terminal 52 and the base portion of the internal connection terminal 53 (that is, the joint portion between the internal connection terminal 53 and the semiconductor package 60) as a fulcrum. Rather, the portion of the conductive column 57 between the rigid sheets 70 and 71 moves with the interface between the rigid sheet 70 and the elastic sheet 56 and the interface between the elastic sheet 56 and the rigid sheet 71 as fulcrums. As a result, the stress applied to the surface of the semiconductor package 60 on which the semiconductor element 51 is mounted is relieved, and the multilayer structure inside the semiconductor package 60 is less likely to be damaged, thereby further improving the reliability of the semiconductor device 50c. Can do.

It is sectional drawing which shows the structure of the flip chip type semiconductor device as an example of the conventional type. It is sectional drawing which shows the structure of the flip chip type semiconductor device as another example of the conventional type. It is sectional drawing which shows the structure of the interposer which concerns on one Embodiment of this invention, and a semiconductor device using the same. It is sectional drawing which showed the simulation result by the model of the semiconductor device which concerns on embodiment of FIG. 3 in contrast with the case of the semiconductor device which concerns on a prior art example. It is a figure which shows the result of the stress analysis of each part when simulation is performed using the model of FIG. It is sectional drawing which shows the structure of the interposer which concerns on the 1st modification of embodiment of FIG. 3, and a semiconductor device using the same. It is sectional drawing which shows the structure of the interposer which concerns on the 2nd modification of embodiment of FIG. 3, and a semiconductor device using the same. It is sectional drawing which shows the structure of the interposer which concerns on the 3rd modification of embodiment of FIG. 3, and a semiconductor device using the same.

Explanation of symbols

50, 50a, 50b, 50c ... semiconductor device,
51. Semiconductor element (chip),
52, 53 ... internal connection terminals (solder bumps),
55, 55a, 55b, 55c ... interposer,
56 ... elastic sheet (plate-like insulator),
56a, 56b ... resin film,
57, 57a ... Conductor column,
57b ... wiring layer,
58, 59 ... Underfill resin,
60 ... Semiconductor package,
61 ... External connection terminal,
70, 71: Rigid sheet (sheet-like member).

Claims (6)

A semiconductor element;
A semiconductor package;
An interposer interposed between the semiconductor element and the semiconductor package, having a plate-like insulator having elasticity, and a plurality of conductors embedded in the thickness direction of the plate-like insulator, The interposer having a first sheet-like member provided on the surface of the plate-like insulator on the side on which the semiconductor element is mounted and having a thermal expansion coefficient comparable to that of the semiconductor element;
The semiconductor element and the semiconductor package are electrically connected via the plurality of conductors, and the semiconductor element is connected to one end of the conductor via a first internal connection terminal. A semiconductor device.   The interposer further includes a second sheet-like member provided on a surface of the plate-like insulator opposite to the side on which the semiconductor element is mounted and having a thermal expansion coefficient comparable to that of the semiconductor package. The semiconductor device according to claim 1. The plate-like insulator is formed by laminating a plurality of resin films, and the conductor is composed of a plurality of conductive pillars that are formed through and stacked in the thickness direction of each of the plurality of resin films. The semiconductor device according to claim 1 .   2. The main material constituting the semiconductor element is made of silicon, and the first sheet-like member is formed of any one of silicon, glass, ceramics, 36 alloy and 42 alloy. 4. The semiconductor device according to any one of 3. Further, the semiconductor package is connected to the other end of the conductor via a second internal connection terminal, and resin is filled between the semiconductor element and the interposer, and between the interposer and the semiconductor package, respectively. The semiconductor device according to claim 1, wherein:   The semiconductor device according to claim 1, wherein a plurality of external connection terminals are provided on a surface of the semiconductor package opposite to a side on which the interposer is mounted.

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