Face down download acoustic

Wednesday 15 September Thursday 16 September Friday 17 September Saturday 18 September Sunday 19 September Monday 20 September Tuesday 21 September Wednesday 22 September Thursday 23 September Friday 24 September Saturday 25 September Sunday 26 September Monday 27 September Tuesday 28 September Wednesday 29 September Thursday 30 September Friday 1 October Saturday 2 October Sunday 3 October Monday 4 October Tuesday 5 October Wednesday 6 October Thursday 7 October Friday 8 October Saturday 9 October Sunday 10 October Monday 11 October Tuesday 12 October Wednesday 13 October Thursday 14 October Friday 15 October Saturday 16 October Sunday 17 October Monday 18 October Tuesday 19 October Wednesday 20 October Thursday 21 October Friday 22 October Saturday 23 October Sunday 24 October Monday 25 October Tuesday 26 October Wednesday 27 October Thursday 28 October Friday 29 October Saturday 30 October Sunday 31 October Monday 1 November Tuesday 2 November Wednesday 3 November Thursday 4 November Friday 5 November Saturday 6 November Sunday 7 November Monday 8 November Tuesday 9 November Wednesday 10 November Thursday 11 November Friday 12 November Saturday 13 November Sunday 14 November Monday 15 November Tuesday 16 November Wednesday 17 November Thursday 18 November Friday 19 November Saturday 20 November Sunday 21 November Monday 22 November Tuesday 23 November Wednesday 24 November Thursday 25 November Friday 26 November Further, because the dam and the bump electrodes were formed separately, the respective heights of the dam and the bump electrodes on the chip device became uneven.

There was therefore a problem that no closed space could be formed when the chip device was facedown mounted on the circuit substrate. Of course, the discontinuous barriers cannot prevent the influx of the resin perfectly. Further, it is necessary to reduce the size of the bump electrodes in order to further reduce the size of the chip device, but the strength of the bump electrodes is weakened if the size of the bump electrodes is reduced.

Generally, according to the aforementioned background art, there has remained a problem that it is impossible to provide any chip device in which high-density mounting can be attained by greater reduction in size of the chip device. Incidentally, as a further background art, JP-A has proposed a structure in which not only an enclosure wall is provided so as to enclose the active region of the surface acoustic wave device but also an upper space enclosed by the enclosure wall is covered with a cover body.

Also in this case, however, the size of the device is increased because bump electrodes are disposed in the outside of the enclosure wall. Furthermore, because the bump electrodes are in positions far from the enclosure wall so as not to be reinforced by the enclosure wall, or the like, the size of the bump electrodes is required to be increased so that the bump electrodes have tolerance to stress at the time of bonding and have a necessary fixation strength.

Accordingly, it is difficult to advance the reduction in size of the bump electrodes. Further, according to the aforementioned background art, it is difficult to make the heights of a plurality of bump electrodes uniform because the plurality of bump electrodes are formed on the main mounting surface by means of bonding or by use of balls, or the like. This invention is designed on the basis of such a knowledge that, when the chip device is face-down mounted on the mount-side substrate, it is only required to provide a gap of several micrometers in the minimum between a main mounting surface of a chip device and a mount-side substrate such as a circuit substrate, or the like.

That is, it is an object of the present invention to provide a chip device in which both the reduction in size of external electrodes as bump electrodes and the reduction in external size of the chip device can be attained to thereby achieve high-density mounting to solve the aforementioned problems, and a method for producing the chip device.

In order to achieve the above object according to an aspect of the present invention, provided is a chip device in which not only an electrode pattern is provided on a main mounting surface of a base but also external electrodes are provided for face-down mounting, characterized in that at least one electrically insulating layer is provided to be put on at least a part of the main mounting surface so as to remain edge portions which do not cover at least apart of the electrode pattern, so that the external electrodes are connected to the electrode pattern while the external electrodes are in contact with the edge portions of the electrically insulating layer.

In the chip device according to the present invention, the edge portion of the electrically insulating layer put on the main mounting surface of the chip device so as to have a predetermined thickness serves to support the external electrode mechanically.

Accordingly, the size of the external electrodes can be reduced, for example, to the order of micrometers or the order of tens of micrometers as the diameter. Incidentally, the electrically insulating layer may be formed by materials other than an inorganic material SiO2 or an organic material such as polyimide, or the like. Further, the external electrodes are not required to be shaped independently, so that the external electrodes may be formed by a thin-film formation method, a thick-film paste printing method, or the like.

In the above chip device, preferably, the electrically insulating layer may include a first electrically insulating layer forming a frame body, and a second electrically insulating layer provided at a distance from the main mounting surface so as to be put on the first electrically insulating layer to protect the main mounting surface.

In this manner, the main mounting surface is covered with the second electrically insulating layer at a gap from the main mounting surface, so that the main mounting surface is protected. Accordingly, not only the chip device becomes easy to handle but also the deposition of foreign matters and the contamination with foreign matters can be prevented.

Accordingly, the reliability of the chip device can be enhanced. In the above chip device, preferably, the main mounting surface may have an active region in which comb-like electrodes for a surface acoustic wave device are formed as a part of the electrode pattern, and the electrically insulating layer is interposed between the main mounting surface and a mount-side substrate while avoiding the active region and comes into close contact with the mount-side substrate to thereby form a closed space which encloses the active region.

Accordingly, even in the case where resin sealing is performed after a surface acoustic wave device in the form of a bare chip is face-down mounted on a mount-side substrate, the characteristic of the surface acoustic wave device never deteriorates. According to another aspect of the present invention, provided is a method for producing a chip device in which external electrodes for face-down mounting are provided on a main mounting surface of a base after an electrode pattern is provided on the main mounting surface, characterized by comprising: an electrically insulating layer formation step of forming at least one electrically insulating layer with a predetermined thickness to be put on at least a part of the main mounting surface so as to remain edge portions which do not cover at least a part of the electrode pattern, and an external electrode formation step of forming external electrodes so that one end of each of the external electrodes is connected to the electrode pattern while the external electrodes are in contact with the edge portions of the electrically insulating layer.

In the method for producing a chip device according to the present invention, the edge portion formed in the electrically insulating layer formation step and the external electrodes formed in the external electrode formation step serve to define the positions and shapes with each other. In the above method for producing a chip device, preferably, the method may further comprise a face-down mounting step of bonding the external electrodes to a mount-side substrate to thereby perform face-down mounting after the external electrode formation step, so that not only the external electrodes are connected to a conductor pattern of the mount-side substrate but also the electrically insulating layer is brought into close contact with both the main mounting surface and the surface of the mount-side substrate in the face-down mounting step.

In this case, the external electrodes come in close contact with the edge portions of the electrically insulating layer when the external electrodes are bonded. Accordingly, the external electrodes and the edge portions of the electrically insulating layer serve to reinforce each other against deformation of anyone of them, so that the bonding strength between the external electrodes and the conductor pattern is enhanced.

Furthermore, when an adhesive resin is used, the electrically insulating layer which is interposed between the chip device and the mount-side substrate fulfills contracting force to attract the two to each other so that the electrically insulating layer serves to enhance mounting strength. Embodiments of a chip device and a method for producing the chip device according to the present invention will be described below with reference to the drawings. In these drawings, the surface acoustic wave device 20 has a structure in which an electrode pattern 25 containing comb electrodes 23 , a ground pattern not shown, etc.

An active region 24 having the comb-like electrodes 23 is formed on the main mounting surface 21 a. Electrode pattern portions extended from the comb electrodes 23 , the ground pattern, etc.

An electrically insulating layer 31 first electrically insulating layer and a protection layer 32 second electrically insulating layer are laminated on the main mounting surface of the surface acoustic wave device 20 while avoiding the active region 24 , so that the layers are provided as an electrically insulating layer containing an electrically insulating resin as a main component.

The electrically insulating layer 31 which is extended from part of the pads 33 to the outside of the pads is formed, for example, by patterning of a light-sensitive polyimide resin. This protection layer 32 is formed, for example, by lamination of light-sensitive dry films on the electrically insulating layer The protection layer 32 covers the active region 24 through the space on the active region Preferably, a clean non-oxidizing or inert gas is enclosed in the closed space, which covers the active region The bump electrodes 22 provided as external electrodes serve as junction electrodes.

The bump electrodes 22 are disposed in an edge portion that is, a frame-like portion which encloses the active region 24 of the electrically insulating layer composed of the electrically insulating layer 31 and the protection layer In this case, the bump electrodes 22 are made to come in close contact with the electrically insulating layer 31 and the protection layer 32 which are formed as inner walls of the holes This bump electrodes 22 are formed from a metal such as copper, nickel, gold, or the like, by a sputtering method, a vapor deposition method, an electrolytic through-hole plating method, or the like.

One end of each of the bump electrodes 22 is electrically connected to the pad 33 formed on the main mounting surface 20 a of the surface acoustic wave device 20 and further connected to the comb-like electrodes 23 , the ground pattern not shown, etc.

The process of facedown mounting a surface acoustic wave device 20 as the chip device in FIGS. As shown in FIG. The bump electrodes 22 of the surface acoustic wave device 20 are positioned in accordance with the position of the conductor pattern Then, ultrasonic wave and pressing force are applied to the bump electrodes 22 , for example, by an ultrasonic bonder.

Thus, as shown in FIG. In this occasion, the electrically insulating layer 31 or the protection layer 32 is closely bonded to the circuit substrate 10 so that the surface acoustic wave device 20 is face-down bonded on the circuit substrate Incidentally, the active region 24 is protected by the protection layer 32 through the closed space, so that the active region 24 is not influenced by bonding.

Further, when an adhesive agent new adhesive resin layer 35 is interposed between the protection layer 32 and the circuit substrate 10 as shown in FIG. When the adhesive agent 35 is used in combination, the protection layer may be omitted.

After the bump electrodes 22 are connected, by means of bonding, to the conductor pattern 11 of the circuit substrate 10 through opening portions from the electrically insulating layer 31 to the protection layer 32 , as shown in FIG. The buffer resin 12 is constituted by silicone resin, or the like, for the double purpose of stress relaxation and electrical insulation.

The exterior resin 13 is constituted by epoxy resin, or the like, for the main purpose of mechanical protection and enhancement of moisture resistance. In the above chip device, preferably, the electrically insulating layer may include a first electrically insulating layer forming a frame body, and a second electrically insulating layer provided at a distance from the main mounting surface so as to be put on the first electrically insulating layer to protect the main mounting surface.

In this manner, the main mounting surface is covered with the second electrically insulating layer at a gap from the main mounting surface, so that the main mounting surface is protected.

Accordingly, not only the chip device becomes easy to handle but also the deposition of foreign matters and the contamination with foreign matters can be prevented. Accordingly, the reliability of the chip device can be enhanced. In the above chip device, preferably, the main mounting surface may have an active region in which comb-like electrodes for a surface acoustic wave device are formed as a part of the electrode pattern, and the electrically insulating layer is interposed between the main mounting surface and a mount-side substrate while avoiding the active region and comes into close contact with the mount-side substrate to thereby form a closed space which encloses the active region.

Accordingly, even in the case where resin sealing is performed after a surface acoustic wave device in the form of a bare chip is face-down mounted on a mount-side substrate, the characteristic of the surface acoustic wave device never deteriorates. According to another aspect of the present invention, provided is a method for producing a chip device in which external electrodes for face-down mounting are provided on a main mounting surface of a base after an electrode pattern is provided on the main mounting surface, characterized by comprising: an electrically insulating layer formation step of forming at least one electrically insulating layer with a predetermined thickness to be put on at least a part of the main mounting surface so as to remain edge portions which do not cover at least a part of the electrode pattern, and an external electrode formation step of forming external electrodes so that one end of each of the external electrodes is connected to the electrode pattern while the external electrodes are in contact with the edge portions of the electrically insulating layer.

In the method for producing a chip device according to the present invention, the edge portion formed in the electrically insulating layer formation step and the external electrodes formed in the external electrode formation step serve to define the positions and shapes with each other. In the above method for producing a chip device, preferably, the method may further comprise a face-down mounting step of bonding the external electrodes to a mount-side substrate to thereby perform face-down mounting after the external electrode formation step, so that not only the external electrodes are connected to a conductor pattern of the mount-side substrate but also the electrically insulating layer is brought into close contact with both the main mounting surface and the surface of the mount-side substrate in the face-down mounting step.

In this case, the external electrodes come in close contact with the edge portions of the electrically insulating layer when the external electrodes are bonded. Accordingly, the external electrodes and the edge portions of the electrically insulating layer serve to reinforce each other against deformation of anyone of them, so that the bonding strength between the external electrodes and the conductor pattern is enhanced.

Furthermore, when an adhesive resin is used, the electrically insulating layer which is interposed between the chip device and the mount-side substrate fulfills contracting force to attract the two to each other so that the electrically insulating layer serves to enhance mounting strength.

Embodiments of a chip device and a method for producing the chip device according to the present invention will be described below with reference to the drawings. In these drawings, the surface acoustic wave device 20 has a structure in which an electrode pattern 25 containing comb electrodes 23 , a ground pattern not shown, etc. An active region 24 having the comb-like electrodes 23 is formed on the main mounting surface 21 a.

Electrode pattern portions extended from the comb electrodes 23 , the ground pattern, etc. An electrically insulating layer 31 first electrically insulating layer and a protection layer 32 second electrically insulating layer are laminated on the main mounting surface of the surface acoustic wave device 20 while avoiding the active region 24 , so that the layers are provided as an electrically insulating layer containing an electrically insulating resin as a main component.

The electrically insulating layer 31 which is extended from part of the pads 33 to the outside of the pads is formed, for example, by patterning of a light-sensitive polyimide resin.

This protection layer 32 is formed, for example, by lamination of light-sensitive dry films on the electrically insulating layer The protection layer 32 covers the active region 24 through the space on the active region Preferably, a clean non-oxidizing or inert gas is enclosed in the closed space, which covers the active region The bump electrodes 22 provided as external electrodes serve as junction electrodes. The bump electrodes 22 are disposed in an edge portion that is, a frame-like portion which encloses the active region 24 of the electrically insulating layer composed of the electrically insulating layer 31 and the protection layer In this case, the bump electrodes 22 are made to come in close contact with the electrically insulating layer 31 and the protection layer 32 which are formed as inner walls of the holes This bump electrodes 22 are formed from a metal such as copper, nickel, gold, or the like, by a sputtering method, a vapor deposition method, an electrolytic through-hole plating method, or the like.

One end of each of the bump electrodes 22 is electrically connected to the pad 33 formed on the main mounting surface 20 a of the surface acoustic wave device 20 and further connected to the comb-like electrodes 23 , the ground pattern not shown, etc.

The process of facedown mounting a surface acoustic wave device 20 as the chip device in FIGS. As shown in FIG. The bump electrodes 22 of the surface acoustic wave device 20 are positioned in accordance with the position of the conductor pattern Then, ultrasonic wave and pressing force are applied to the bump electrodes 22 , for example, by an ultrasonic bonder.

Thus, as shown in FIG. In this occasion, the electrically insulating layer 31 or the protection layer 32 is closely bonded to the circuit substrate 10 so that the surface acoustic wave device 20 is face-down bonded on the circuit substrate Incidentally, the active region 24 is protected by the protection layer 32 through the closed space, so that the active region 24 is not influenced by bonding.

Further, when an adhesive agent new adhesive resin layer 35 is interposed between the protection layer 32 and the circuit substrate 10 as shown in FIG. When the adhesive agent 35 is used in combination, the protection layer may be omitted. After the bump electrodes 22 are connected, by means of bonding, to the conductor pattern 11 of the circuit substrate 10 through opening portions from the electrically insulating layer 31 to the protection layer 32 , as shown in FIG.

The buffer resin 12 is constituted by silicone resin, or the like, for the double purpose of stress relaxation and electrical insulation. The exterior resin 13 is constituted by epoxy resin, or the like, for the main purpose of mechanical protection and enhancement of moisture resistance.

Referring to FIG. Then, as shown in FIG. Further, as shown in FIG. Incidentally, because the upper surface of the active region 24 on the main mounting surface side is sealed with the protection layer 32 , there is a particular advantage that plating can be made.

According to this embodiment of the present invention, the following effects can be obtained. Because the bump electrodes 22 as external electrodes are provided in the edge portions of the electrically insulating layer electrically insulating resin layer in this embodiment composed of the electrically insulating layer 31 and the protection layer 32 , reduction in size of the shape of the chip device can be attained compared with the background-art chip device having the structure in which the bump electrodes are disposed in the outside of the dam frame or barriers.

Because the bump electrodes 22 are formed so as to be in contact with the edge portions of the electrically insulating layer and reinforced by the electrically insulating layer, the size of the bump electrodes 22 can be reduced. Further, when configuration is made so that the electrically insulating layer is brought into contact with and bonded to the circuit substrate at the time of face-down bonding to the circuit substrate 10 through the bump electrodes 22 , the bonding strength between the bump electrodes 22 and the conductor pattern 11 of the circuit substrate can be enhanced.

In the background art, when the surface acoustic wave device sealed by a glass casing, a ceramic package, or the like, is not blocked from the external environment, slight moisture or foreign matter is deposited on the surface of the active region to there by make the characteristic of the active region deteriorate. According to the configuration, in this embodiment of the present invention, however, no deterioration of characteristic in handling occurs because the active region 24 is covered and sealed with the protection layer This effect is not limited to the embodiment using the surface acoustic wave device as an example.

The same effect as described above is obtained also when the present invention is applied to a semiconductor chip. Because a plurality of bump electrodes 22 are formed simultaneously by a thin-film technique and a film-forming technique such as plating, or the like, the heights of the plurality of bump electrodes 22 can be equalized.

In the aforementioned embodiment of the present invention, a method using a light-sensitive dry film has been described as an example of the method for forming a protection layer. Other than the aforementioned method, it is possible to employ any method in which, for example, holes are formed in advance in a bonding sheet using an adhesive polyimide film, or the like, before the sheet thus treated is bonded to the electrically insulating layer. Alternatively, holes may be formed by use of a laser beam after a bonding sheet using an adhesive polyimide film, or the like, in which the holes have been not formed yet is bonded to the electrically insulating layer.

Further, an anisotropic electrically conductive sheet maybe used as the protection layer.