JP2007189005A - Mounting structure of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting structure of a semiconductor device in which the underfill portion can be protected against formation of a void, certainty of flip-chip connection can be enhanced, and production cost of a mounting substrate can be prevented from increasing. <P>SOLUTION: On the periphery of a semiconductor device mounting portion 14, a recess 22 is formed in the vicinity of the outer circumferential edge of the semiconductor device 11. The recess 22 decelerates the flow velocity of resin flowing around the semiconductor device 11. The semiconductor device 11 side end of the recess 22 is located closer to the mounting substrate 13 side than the major surface 11a of the semiconductor device 11. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a mounting structure of a semiconductor device, and more particularly to a technique effective in a technique for injecting a sealing resin into a gap generated between a semiconductor device and a mounting substrate in a flip chip mounting structure.

  A flip chip structure is known as a semiconductor device mounting structure. The flip-chip structure is a structure in which the semiconductor device is mounted on the mounting substrate with the surface on which the bump electrode of the semiconductor device is formed and the surface on which the pad electrode on the mounting substrate is formed facing each other. Such a flip chip structure can minimize the height required for mounting and the board area as compared with conventional wire bonding and mounting structures using lead frames. The mounting structure is useful for responding to the trend of lightness, thinness, and miniaturization.

  When a semiconductor device is flip-chip mounted on a mounting substrate, the gap between the semiconductor device and the mounting substrate is usually filled with a sealing resin called underfill to protect the connection between the semiconductor device and the mounting substrate. There is a need to.

  Here, the semiconductor device may be a so-called BGA (ball grid array) or CSP (chip size package), or may be a bare chip. In addition, the semiconductor device may be a wafer level package which is completed by forming a final insulating film and bump electrodes in a semiconductor wafer state and then separating them.

  The purpose of forming the underfill is to mechanically protect the connecting portion and to disperse the thermal stress generated by the rise and fall of the ambient temperature due to the difference in linear thermal expansion coefficient between the semiconductor device and the mounting substrate. .

  In the situation without the above-mentioned underfill, the temperature of the mounting structure increases or decreases, and the semiconductor device generates heat due to power on / off of the electronic device itself. It is known that repeated distortion occurs in the connection portion with the mounting substrate, and the connection portion easily breaks.

  The underfill has an effect of dispersing the strain over the entire surface where the semiconductor device and the mounting substrate face each other, and helps to improve the reliability of the connection portion.

  When the semiconductor device is a bare chip, the surface on which the semiconductor element included in the semiconductor device is formed is only covered with a thin passivation film. Such a semiconductor element can be protected by underfill from humidity and harmful gases in the environment where the electronic device is used.

  When forming the underfill, after mounting the semiconductor device on the mounting substrate, after dropping the liquid resin around the semiconductor device and filling the gap between the semiconductor device and the mounting substrate with the liquid resin by capillary action The liquid resin is cured by heating.

  In such an underfill formation method, an unfilled portion that is not filled with a liquid resin (hereinafter referred to as “void portion”) remains in the gap between the semiconductor device and the mounting substrate, and the reliability of the mounting structure There is a problem of worsening.

  More specifically, if there is a void portion in the gap between the semiconductor device and the mounting substrate, moisture in the usage environment permeates through the gap between the resin molecules constituting the underfill and easily collects in the void portion. If the moisture of the moisture accumulated in the void portion is condensed due to a decrease in the ambient temperature, there is a risk of causing problems such as a leak failure in the semiconductor element of the semiconductor device.

  In addition, when a solder reflow process or the like is performed in a state where there is moisture in the void part, the void part expands rapidly due to vaporization of the moisture in the void part due to a rapid increase in the ambient temperature due to the reflow process or the like. Will burst. As a result, cracks and peeling may occur in the portions other than the void portion of the underfill, which may cause a problem that the underfill function is not provided.

  Therefore, it is necessary to eliminate the void portion in the underfill.

  Conventionally, as a method for preventing the formation of the void portion, there is one described in JP-A-10-50892 (Patent Document 1).

  In Japanese Patent Laid-Open No. 10-50892, when a liquid resin is dropped around the semiconductor device, the liquid resin wraps around the periphery of the semiconductor device as compared with the speed of the liquid resin entering the gap between the semiconductor device and the mounting substrate. It has been pointed out that when the speed of the liquid resin is higher, a void portion is formed and a problem due to the void portion occurs.

  More specifically, an imaginary line passing through the position where the liquid resin is dropped around the semiconductor device and the center of the semiconductor device is considered, and this imaginary line intersects with the outer periphery of the semiconductor device on the side opposite to the liquid resin dropping side. When a point is considered, it is an idea that whether or not a void portion is generated is determined by a difference in arrival times of two types of resin flows to this point. That is, when the resin flowing in the periphery of the semiconductor device reaches the point earlier than the resin flowing in the gap, a void portion is generated.

  In order to eliminate the void portion generated for such a reason, Japanese Patent Application Laid-Open No. 10-50892 proposes a structure in which a protrusion is provided on a part of the semiconductor substrate peripheral portion on the mounting substrate.

  However, JP-A-10-50892 has the following problems. This problem will be described with reference to FIG.

  FIG. 6 is a schematic cross-sectional view of a semiconductor device mounting structure disclosed in Japanese Patent Laid-Open No. 10-50892.

  In the mounting structure, the semiconductor device 111 is mounted on the mounting substrate 113, and the connection portion 117 is formed in the gap between the mounting substrate 113 and the semiconductor device 111. The connection portion 117 includes a bump electrode 112 and a pad electrode 116 connected to the bump electrode 112.

  An underfill portion 121 is formed on the surface of the mounting substrate 113 on the semiconductor device 111 side. This underfill portion 121 fills a gap between the mounting substrate 113 and the semiconductor device 111.

  Further, a protrusion 171 located near the outer periphery of the semiconductor device 111 is formed on the surface of the mounting substrate 113 on the semiconductor device 111 side. Due to the protrusions 171, the resin flow around the semiconductor device 111 is hindered, and the generation of voids is eliminated.

  However, in recent years when the semiconductor device 113 is miniaturized as the number of pins is increased and the pitch of the bump electrodes 112 is reduced, a protrusion such as the protrusion 171 is actually provided, and the resin flow around the periphery of the semiconductor device 113 It has become difficult to inhibit.

  One of the factors that make it difficult to inhibit the resin flow around the semiconductor device is a narrowing of the gap between the semiconductor device 111 and the mounting substrate 113. One of the factors is related to the narrowing of the bump electrode pitch.

  That is, if the bump electrode pitch is reduced, the area of the bump electrode 112 is reduced, so that the difficulty in manufacturing the bump electrode 112 is avoided, and the height of the bump electrode 112 is also reduced. When the semiconductor device 111 using the bump electrode 112 having a reduced height is flip-chip connected, the gap between the semiconductor device 111 and the mounting substrate 113 is naturally narrowed.

  In many cases, both the bump electrode 112 and the pad electrode 116 are formed of Au, and a thermocompression method or an ultrasonic connection method is used to connect the bump electrode 112 and the pad electrode 116. When these methods are employed, the gap between the semiconductor device 111 and the mounting substrate 113 is further increased in order to achieve metal connection between the bump electrode 112 and the pad electrode 116 by crushing the bump electrode 112 to some extent. It becomes narrower.

  On the other hand, the narrowing of the bump electrode pitch is accompanied by the narrowing of the pad electrode pitch on the mounting substrate 113 and the substrate wiring interval. As a result, the potential gradient due to the potential difference applied between the substrate wirings is increased. As a result, the problem of reliability of insulation resistance due to humidity in the air has become serious. In other words, the occurrence of ion migration has become a problem due to the potential gradient between the substrate wirings and the moisture in the air.

  In order to prevent ion migration between the substrate wirings, it is effective to prevent moisture from entering between the wirings. For this reason, an organic resin film is formed on the mounting substrate 113 as close as possible to the semiconductor device 111 to protect the substrate wiring from moisture as much as possible.

  FIG. 7 shows a schematic cross-sectional view of the mounting structure of the semiconductor device in the case where the protruding portion 171 is installed in the peripheral portion of the semiconductor device 111 while reflecting such a situation.

  On the mounting substrate 113, an organic resin film 115 is formed at a place other than the semiconductor device mounting portion 114. Further, a protrusion 171 is formed on the organic resin film 115.

  The organic resin film 115 needs to have a certain thickness in order to maintain insulation reliability, and usually requires a thickness of about 10 to 20 μm. In order to maintain moisture-resistant insulation reliability, the organic resin film 115 is formed to the immediate vicinity of the outer edge of the semiconductor device 111. After the semiconductor device 111 is mounted on the semiconductor device mounting portion 114, the organic resin film 115 is organically bonded to the outer edge of the semiconductor device 111. The gap with the opening edge of the resin film 111 is narrow, for example, only about 100 μm. Therefore, the protrusion 171 is provided on the organic resin film 115.

  By the way, the height of the bump electrode 112 depends on a manufacturing method, a pitch, and the like. The Au bump electrode 112 used in the above-described thermocompression bonding method and ultrasonic connection method is widely formed by a plating method, and the maximum height is about 50 μm at most because of the productivity of the plating method. In some cases, the pitch of the bump electrodes 112 is reduced to about 25 μm due to the narrow pitch.

  When the height of the bump electrode 112 is as low as about 25 μm, considering that the bump electrode 112 is crushed during flip chip connection, the height of the gap between the semiconductor device 111 and the mounting substrate 113 is , Smaller than 20 μm. As a result, the height of the gap between the semiconductor device 111 and the mounting substrate 113 is substantially the same as the thickness of the organic resin film 115.

  Therefore, the height from the surface of the mounting substrate 113 on the semiconductor device 111 side to the upper surface of the protrusion 171 (the surface opposite to the surface on the mounting substrate 113 side) is from the surface of the mounting substrate 113 on the semiconductor device 111 side. In some cases, the height of the lower surface of the semiconductor device 111 (the surface on the mounting substrate 113 side) becomes higher. In this case, when the semiconductor device 111 is flip-chip connected, the semiconductor device 111 and the protrusion 171 come into contact with each other due to a slight positional deviation of the opening of the organic resin film 115 due to variations in the manufacturing of the mounting substrate 113, so that the flip-chip connection This causes a problem that cannot be performed satisfactorily.

  In addition, the organic resin film 115 is usually formed on the entire main surface of the mounting substrate 113 by selective removal by photolithography after application formation or selective application by printing or the like. Usually, since it is formed with a substantially uniform film thickness, it is necessary to add a step of providing a separate protrusion for forming the protrusion 171. Since it is necessary to form the organic resin film 115 again or selectively apply another material, which leads to an increase in cost, it cannot be said to be an efficient method.

As described above, the related art has problems related to the reliability of flip chip connection and the manufacturing cost of the mounting substrate 113.
Japanese Patent Laid-Open No. 10-50892

  Accordingly, an object of the present invention is to prevent the formation of a void portion in the underfill portion, further improve the reliability of flip chip connection, and prevent an increase in manufacturing cost of the mounting substrate. Another object of the present invention is to provide a mounting structure for a semiconductor device.

In order to solve the above problems, the mounting structure of the semiconductor device of the present invention is:
A semiconductor device in which a plurality of bump electrodes are arranged on the main surface;
A mounting substrate having a semiconductor device mounting portion on which the semiconductor device is mounted, and a plurality of pad electrodes formed corresponding to the positions of the plurality of bump electrodes on the surface of the semiconductor device mounting portion on the semiconductor device side; ,
With
In the mounting structure of the semiconductor device in which the plurality of bump electrodes and the plurality of pad electrodes are connected by flip chip bonding, and a resin is filled between the semiconductor device and the mounting substrate.
A recess that is formed around the semiconductor device mounting portion and is located in the vicinity of the outer periphery of the semiconductor device, and that can reduce the flow rate of the resin flowing around the semiconductor device,
An end of the recess on the semiconductor device side is located on the mounting substrate side with respect to the main surface of the semiconductor device.

  According to the mounting structure of the semiconductor device having the above configuration, when liquid resin is dropped on the dropping position around the semiconductor device in order to fill the resin between the semiconductor device and the mounting substrate, the periphery of the semiconductor device mounting portion Since a recess is formed in the vicinity of the outer peripheral edge of the semiconductor device, the liquid resin flows around the semiconductor device and flows into the recess. Thus, the liquid resin cannot advance beyond the recess until the space in the recess is filled. Depending on the time that the liquid resin fills the space in the recess, the progress of the liquid resin that goes around the periphery of the semiconductor device is delayed. That is, the flow rate of the liquid resin flowing around the semiconductor device is reduced by the recess.

  Therefore, the flow rate of the liquid resin flowing through the gap between the semiconductor device and the mounting substrate is faster than the flow rate of the liquid resin flowing around the semiconductor device, and the liquid resin flows between the semiconductor device and the semiconductor device mounting portion. There is an effect that void generation does not occur.

  Further, since the end of the recess on the semiconductor device side is located closer to the mounting substrate than the main surface of the semiconductor device, the recess is prevented from coming into contact with the semiconductor device during flip chip bonding, and the reliability of flip chip connection is improved. be able to.

  Moreover, since the said recessed part can be formed in a mounting substrate, for example, the material for only forming a recessed part is unnecessary, and the increase in manufacturing cost can be prevented.

In the mounting structure of the semiconductor device of one embodiment,
In order to fill the resin between the semiconductor device and the mounting substrate, when dropping a liquid resin to the dropping position around the semiconductor device,
A point that is one half of the entire circumference of the outer peripheral edge along the outer peripheral edge of the semiconductor device from the dropping position is the farthest outer peripheral path, and a linear distance from the dropping position with respect to the outer peripheral edge of the semiconductor device. When the farthest point is the farthest distance,
A path reaching the farthest outer peripheral path from the dropping position along the outer peripheral edge of the semiconductor device, and a farthest distance from the dropping position along the outer peripheral edge of the semiconductor device. The recess is formed in at least one of the path and the path.

  According to the semiconductor device mounting structure of the above embodiment, the path reaching the farthest outer peripheral path from the dropping position along the outer peripheral edge of the semiconductor device and the shortest distance from the dropping position along the outer peripheral edge of the semiconductor device. Since the recess is formed in at least one of the path that reaches the farthest distance in distance, the liquid resin that flows between the semiconductor device and the mounting substrate is more peripheral than the liquid resin that flows along the outer peripheral edge of the semiconductor device. It is possible to quickly reach at least one of the farthest point and the farthest distance point.

  Therefore, it is possible to reliably prevent a resin void from being generated in the vicinity of at least one of the farthest outer peripheral path and the farthest distance between the semiconductor device and the semiconductor device mounting portion.

In the mounting structure of the semiconductor device of one embodiment,
The recess includes the dropping position.

  In this embodiment, it is desirable that the opening edge of the recess is a substantially rectangular shape in which a side parallel to one side of the outer peripheral edge of the semiconductor device in the vicinity is longer than a side perpendicular to the side.

  According to the mounting structure of the semiconductor device of the embodiment, since the recess includes the dropping position, the liquid resin dripped at the dropping position is liquid along the outer peripheral edge of the semiconductor device only for the time required to fill the space in the recess. The time when the resin begins to flow is delayed. Thereby, it is possible to surely advance the time when the gap between the semiconductor device and the semiconductor device mounting portion is filled with the liquid resin rather than the time when the semiconductor device is surrounded by the liquid resin.

  Therefore, it is possible to reliably prevent generation of voids in the resin between the semiconductor device and the semiconductor device mounting portion.

  Moreover, when the said recessed part is the said rectangle, the effect can be heightened further.

In the mounting structure of the semiconductor device of one embodiment,
The concave portion is adjacent to a side other than a side passing through a region near the farthest outer peripheral path with respect to the outer peripheral edge of the semiconductor device mounting portion.

  According to the mounting structure of the semiconductor device of the above-described embodiment, the peripheral portion of the semiconductor device is wrapped around the peripheral portion of the semiconductor device mounting portion by making the recess adjacent to a side other than the side passing through the region near the farthest outer peripheral path. Thus, the concave portion is positioned in the middle of the flow path of the liquid resin that flows in the manner described above.

  Therefore, the speed of the liquid resin that flows so as to wrap around the periphery of the semiconductor device can be reliably reduced.

In the mounting structure of the semiconductor device of one embodiment,
There are two sides other than the side that passes through the region near the farthest point of the outer peripheral path, and the recess is adjacent to at least one of the two sides.

  According to the mounting structure of the semiconductor device of the above embodiment, the liquid resin flows between the semiconductor device and the semiconductor device mounting portion so that at least one of the two sides is adjacent to the concave portion, so Compared to the time to reach the farthest point and the farthest distance, the time when the liquid resin reaches the farthest point of the outer peripheral path from the dripping position along the outer peripheral edge of the semiconductor device and the liquid resin from the dripping position to the farthest point of the semiconductor device. The time to reach the farthest point at the shortest distance along the outer peripheral edge can be reliably increased.

In the mounting structure of the semiconductor device of one embodiment,
The bottom surface of the recess is formed of a material excellent in wettability with the resin.

  According to the mounting structure of the semiconductor device of the above embodiment, since the bottom surface of the recess is formed of a material excellent in wettability with the resin, the resin does not repel the bottom surface of the recess. The flow rate of the resin flowing around can be surely decelerated.

  Further, it is desirable that the side surface of the recess is also made of a material excellent in wettability with the resin because the flow of the resin into the recess is not hindered.

In the mounting structure of the semiconductor device of one embodiment,
The bottom surface of the recess includes the same metal as the metal included in the pad electrode.

  According to the mounting structure of the semiconductor device of the above embodiment, since the resin does not repel the bottom surface of the recess when the bottom surface of the recess contains metal, the flow rate of the resin flowing around the semiconductor device is surely ensured. It can be decelerated.

  In addition, since the metal is the same as the metal included in the pad electrode, the bottom surface of the recess and the pad electrode can be formed in the same process, so that an increase in cost associated with the formation of the recess can be prevented.

In the mounting structure of the semiconductor device of one embodiment,
On the mounting substrate, an organic resin film is formed so as to surround the semiconductor device,
An organic resin film formed so as to surround the semiconductor device and having a main opening and an additional opening adjacent to the main opening,
The main opening overlaps the semiconductor device mounting portion and is approximately the same size as the semiconductor device,
The recess includes the additional opening.

  According to the mounting structure of the semiconductor device of the above embodiment, since the recess is formed by the additional opening adjacent to the main opening of the organic resin film, the recess can be formed together with the main opening of the organic resin film. As a result, it is possible to prevent an increase in cost due to the formation of the recess.

In the mounting structure of the semiconductor device of one embodiment,
The substrate wiring drawn from the pad electrode is formed outside the region where the additional opening is formed,
The additional opening has a metal pattern at the bottom made of the same kind of metal as the material of the substrate wiring.

  According to the mounting structure of the semiconductor device of the above embodiment, the substrate wiring is not exposed from the additional opening by forming the substrate wiring extracted from the pad electrode in a region other than the region where the additional opening is formed. As a result, the moisture-proof insulation reliability can be improved.

  In addition, since the additional opening has a metal pattern made of the same type of metal as the material of the substrate wiring at the bottom, the metal pattern and the substrate wiring can be formed in the same process, resulting in an increase in cost associated with the formation of the metal pattern. Can be prevented.

  According to the mounting structure of the semiconductor device of the present invention, in order to fill the resin between the semiconductor device and the mounting substrate, when the liquid resin is dropped at the dropping position around the semiconductor device, the semiconductor device is mounted around the mounting portion. The liquid resin flows around the semiconductor device and flows into the recess due to the formation of the recess located in the vicinity of the outer peripheral edge of the semiconductor device, so that the flow rate of the liquid resin flowing around the semiconductor device is reduced. .

  Therefore, the flow rate of the liquid resin flowing through the gap between the semiconductor device and the mounting substrate is faster than the flow rate of the liquid resin flowing around the semiconductor device, and the liquid resin flows between the semiconductor device and the semiconductor device mounting portion. Generation of voids can be prevented.

  Further, since the end of the recess on the semiconductor device side is located closer to the mounting substrate than the main surface of the semiconductor device, the recess is prevented from coming into contact with the semiconductor device during flip chip bonding, and the reliability of flip chip connection is improved. be able to.

  Moreover, since the said recessed part can be formed in a mounting substrate, for example, the material for only forming a recessed part is unnecessary, and the increase in manufacturing cost can be prevented.

  Further, since the generation of the void portion can be prevented, a highly reliable flip chip mounting structure can be obtained. In particular, a flip chip mounting structure with high moisture resistance insulation reliability can be obtained.

  Hereinafter, the mounting structure of the semiconductor device of the present invention will be described in detail with reference to the illustrated embodiments.

[Example 1]
FIG. 1A shows a schematic top view of a mounting structure of a semiconductor device according to Embodiment 1 of the present invention. 1B is a schematic cross-sectional view taken along line IB-IB in FIG. 1A.

  1A and 1B, the mounting structure includes a mounting substrate 13 including a semiconductor device mounting portion 14, a semiconductor device 11 mounted on the semiconductor device mounting portion 14, and a semiconductor device mounting portion of the semiconductor device 11. A plurality of bump electrodes 12 formed on the surface on the 14 side and a plurality of pad electrodes 16 formed on the surface on the semiconductor device 11 side of the semiconductor device mounting portion 14 so as to correspond to the positions of the respective bump electrodes 12. And.

  The bump electrode 12 and the pad electrode 16 are connected to each other to form a connection portion 17. In other words, the connection portion 17 includes the bump electrode 12 and the pad electrode 16 connected to the bump electrode 12.

  The semiconductor device mounting portion 14 corresponds to a portion on the mounting substrate 13 where the semiconductor device 11 is mounted. The surface of the semiconductor device mounting portion 14 on the semiconductor device 11 side is approximately the same size as the surface of the semiconductor device 11 on the semiconductor device mounting portion 14 side.

  On the surface of the mounting substrate 13 on the semiconductor device 11 side, two recesses 22 adjacent to the outer peripheral edge of the semiconductor device mounting portion 14 are formed. The recess 22 has a bottom surface lower than the outermost surface of the surface of the mounting substrate 13 on which the semiconductor device 11 is mounted (the surface of the semiconductor device mounting portion 14 on the semiconductor device 11 side). The recess 22 is located outside the semiconductor device mounting portion 14. Further, the end of the recess 22 on the semiconductor device 11 side is located closer to the mounting substrate 13 than the main surface 11 a of the semiconductor device 11.

  A plurality of substrate wirings 18 are formed on the surface of the mounting substrate 13 on the semiconductor device 11 side. Some of the plurality of substrate wirings 18 are drawn from the pad electrode 16 to the outside of the semiconductor device mounting portion 14 and connected to another circuit element (not shown). Some of the plurality of substrate wirings 18 are led out from the pad electrode 16 to the inside of the semiconductor device mounting portion 14 and connected to another circuit element (not shown) via the via wiring 19. Thereby, exposure of the board | substrate wiring 18 by the recessed part 22 is avoided.

  An organic resin film 15 is formed on the surface of the mounting substrate 13 on the semiconductor device 11 side in order to protect the substrate wiring 18. The organic resin film 15 is not formed on the semiconductor device mounting portion 14 and is formed excluding the concave portion 22. That is, the organic resin film 15 has a main opening 10 that overlaps the semiconductor device 11 and the semiconductor device mounting portion 14, and an additional opening 20 that is adjacent to the main opening 10. Such an organic resin film 15 can be formed of, for example, a solder resist.

  The formation method of the said recessed part 22 is not specifically limited, Various. For example, after manufacturing the substrate to be the mounting substrate 13, the recess 22 may be formed by performing cutting using an end mill at a location adjacent to the outer peripheral edge of the semiconductor device mounting portion 14. Further, when a multilayer substrate is used as an example of the mounting substrate 13, the inner layer portion is formed as usual, and holes are formed in the corresponding portions of one or two insulating layers from the side closer to the semiconductor device mounting surface. The recess 22 may be formed by laminating the inner layer and the insulating layer. Regardless of which method is used, the recesses 22 are provided during manufacture of the mounting substrate 13. Using such a mounting substrate 13, a flip chip mounting structure is formed by a conventional technique such as thermocompression bonding, and a liquid resin is filled in a gap between the semiconductor device 11 and the mounting substrate 13.

  The effect of the recess 22 is exhibited in the liquid resin filling step. Hereinafter, the description will be given with reference to FIG. 2A.

  In FIG. 2A, reference numeral 23 denotes a liquid resin discharge position 23 as an example of a dropping position. When an appropriate amount of liquid resin is discharged to the liquid resin discharge position 23 using a dispenser or the like, two types of resin flows are generated. The driving principle of these two types of resin flows is a capillary flow.

  One of the two types of resin flows is a flow as indicated by an arrow 31 and flows around the periphery of the semiconductor device. The other of the two types of resin flows is a flow as indicated by an arrow 32, and advances through the gap between the semiconductor device 11 and the semiconductor device mounting portion 14 toward the center of the semiconductor device 11.

  When the virtual line 33 passing through the liquid resin discharge position 23 and the center of gravity 34 of the semiconductor device 11 is considered, there are two points where the virtual line 33 intersects the outer peripheral edge of the semiconductor device 11. Of these two points, the point away from the liquid resin discharge position 23 is referred to as a point A. When the time T1 when the resin flow indicated by the arrow 31 reaches the point A from the liquid resin discharge position 23 and the time T2 when the resin flow indicated by the arrow 32 reaches the point A from the liquid resin discharge position 23 are compared, the time T1 is obtained. If the time T2 is smaller than that, void generation does not occur. This is because the resin flow 32 indicated by the arrow 32 advances while pushing out air existing in the gap between the semiconductor device 11 and the mounting substrate 13.

  Conversely, if the resin flow indicated by the arrow 31 reaches the point A earlier than the resin flow indicated by the arrow 32, that is, if the time T2 is greater than the time T1, the air existing in the gap between the semiconductor device 11 and the mounting substrate. However, the liquid resin surrounds the semiconductor device 11 before it is completely extruded by the resin flow indicated by the arrow 32. As a result, voids remain in the liquid resin and the underfill portion where it is cured.

  Here, in the flip chip mounting structure in which the concave portion 22 is formed, when the liquid resin is dropped at the liquid resin discharge position 23, the liquid resin flows and flows around the semiconductor device as indicated by an arrow 31. At this time, at the position of the concave portion 22, a time for filling the space in the concave portion 22 is once spent. For this reason, the liquid resin flowing as shown by the arrow 31 reaches the point A later than the liquid resin flowing as shown by the arrow 32 by the time it takes to fill the space in the recess 22.

  About the position where the said recessed part 22 is formed, you may make it enter into the semiconductor device mounting part 14 a little inside including the outer periphery of the semiconductor device mounting part 14. FIG. That is, the recess 22 may be formed so that a part of the recess 22 overlaps the semiconductor device 11. Furthermore, it is desirable to form the recess 22 so as to be adjacent to the side excluding the side passing through the point A on the outer peripheral edge of the semiconductor device 11.

  If the concave portion adjacent to the side passing through the point A is formed on the outer peripheral edge of the semiconductor device 11, the liquid resin flowing as indicated by the arrow 32 is moved to the point A earlier than the liquid resin flowing as indicated by the arrow 31. Although the goal of reaching is reached, it is less effective for the purpose of preventing void formation. This is because the concave portion is adjacent to the side passing through the point A on the outer peripheral edge of the semiconductor device 11, so that the liquid resin flowing as shown by the arrow 31 is just before surrounding the semiconductor device 11, and the flow velocity is reduced by the concave portion. Because. That is, when the concave portion is formed, the effect of pushing out the air existing in the gap between the semiconductor device 11 and the semiconductor device mounting portion 14 with the flowing liquid resin as indicated by the arrow 32 is slightly reduced.

  Therefore, it is desirable to form the recess formed to reduce the flow rate of the flowing liquid resin as indicated by the arrow 31 so as to be adjacent to the side excluding the side passing through the point A on the outer peripheral edge of the semiconductor device 11. . At this time, a part of the recess may overlap the semiconductor device 11 or may not overlap.

  It is desirable that a material that improves the wettability of the liquid resin is applied to the bottom surface of the recess 22. It is more desirable to apply the above material to the bottom and side surfaces of the recess 22. As the material, a resin having a hydrophilic functional group such as a hydroxyl group or a carboxyl group is desirable. For example, it is desirable to use a polar hydrogenated oligomer resin as the resin.

  If the material is applied to at least the bottom surface of the recess 22, the recess 22 is reliably filled with the liquid resin after the resin flow indicated by the arrow 31 reaches the recess 22.

  If the bottom surface of the concave portion 22 is poor in wettability with the liquid resin, the filling of the concave portion 22 with the flowing liquid resin does not occur as shown by the arrow 31, so that the effect of delaying the flow of the liquid resin is reduced. There is. In order to prevent such a situation, it is desirable to perform the coating process on at least the bottom surface of the recess 22.

  As such, the liquid resin filled in the gap between the semiconductor device 11 and the semiconductor device mounting portion 14 is finally cured by being heated to a temperature of about 150 ° C., as shown in FIG. 2B. In addition, the underfill portion 21 is formed.

[Example 2]
FIG. 3 shows a schematic cross-sectional view of the mounting structure of the semiconductor device of Example 2 of the present invention. 3, the same reference numerals as those in FIGS. 1A and 1B are assigned to the same components as those in the first embodiment shown in FIGS. 1A and 1B.

  The difference of the second embodiment from the first embodiment is that a mounting substrate 213 that is a multilayer substrate is used, and the position and shape of the recess 22 are not different from those of the first embodiment.

  The mounting substrate 213 includes an insulating layer 41 close to the semiconductor device 11 and an insulating layer 42 remote from the semiconductor device 11.

  The insulating layer 41 is composed of one insulating layer, but may be formed by laminating a plurality of insulating layers. On the other hand, a wiring 43 is formed on the insulating layer 42. The material of the wiring 43 is not particularly limited, but is Cu, for example.

  It should be noted that a metal land 44 is formed at the bottom of the recess 22. The metal land 44 and the wiring 43 include at least part of the same metal.

  Since the wiring 43 is usually made of Cu, the metal land 44 is also configured to contain Cu. The metal land 44 may be formed in such a manner that Cu is exposed.

  Alternatively, the pad electrode 16 is present on the main surface of the mounting substrate 213, and the pad electrode 16 is usually configured to include Cu. In some cases, Ni plating, Au plating, or the like is performed on the Cu. In such a case, Ni plating, Au plating, etc. may be made on Cu on the metal land 44 as well.

  Since the metal land 44 is formed at the bottom of the recess 22, the liquid resin is not repelled at the bottom of the recess when the liquid resin is filled after the flip chip mounting structure is formed. Thereby, the time required for the liquid resin flowing along the outer peripheral edge of the semiconductor device 11 to fill the space in the recess 22 is generated, and the progress of the liquid resin can be surely delayed during this time. Therefore, the liquid resin does not surround the semiconductor device 11 before the air in the gap between the semiconductor device 11 and the mounting substrate 213 is pushed out by the liquid resin, and the generation of voids can be prevented.

  There is such an effect, and there is no need to add an extra step when manufacturing the mounting structure 213 shown in FIG. That is, since the metal land 44 can be formed together with the wiring 43 on the insulating layer 42 at the time of manufacturing the mounting substrate 213, there is no increase in the manufacturing process accompanying the formation of the metal land 44. This can be dealt with by simply designing the pattern in the photolithography of the metal foil previously formed on the insulating layer 42 as such. Furthermore, a through hole that should be part of the recess 22 is formed in the insulating layer 41. The formation of the through holes is usually performed by slightly increasing the number of vias since interlayer via holes are usually formed in the multilayer substrate.

  As described above, after forming the insulating layer 42, the wiring 43, the metal land 44, and the insulating layer 41, the mounting substrate 213 can be obtained by performing a normal pressing process. Then, after applying the organic resin film 15 as the surface layer, if necessary, Ni plating or Au plating is applied to the pad electrode 16 to obtain a metal land 44 plated with Ni or Au. .

Example 3
FIG. 4A shows a schematic top view of the mounting structure of the semiconductor device according to the third embodiment of the present invention. FIG. 4B is a schematic cross-sectional view taken along the line IVB-IVB in FIG. 4A. 4A and 4B, the same components as those in the first embodiment shown in FIGS. 1A and 1B are denoted by the same reference numerals as those in FIGS. 1A and 1B. Moreover, the arrow of FIG. 4B has shown the discharge direction to the liquid resin discharge position 23 of liquid resin.

  In Example 3, as shown in FIGS. 4A and 4B, the number, shape, and position of the recesses 22, the shape of the organic resin film 15, the position of the substrate wiring 18, and the position of the via wiring 19 are described in Example 1. Is different.

  A metal land (not shown) described with reference to FIG. 3 is formed on the bottom of the concave portion 22, or a material excellent in wettability with a liquid resin such as a polar hydrogenated oligomer resin is formed on the bottom surface or side surface thereof. It may be provided on the bottom or side.

  In the third embodiment, the recess 22 is formed at a position where the liquid resin is applied. That is, the recess 22 includes the liquid resin discharge position 23. After forming the flip chip mounting structure as usual, the liquid resin is discharged to the liquid resin discharge position 23. Then, the flow of the liquid resin toward the gap between the semiconductor device 11 and the semiconductor device mounting portion 14 starts immediately, but the flow of the liquid resin that goes around the peripheral portion of the semiconductor device 11 fills the space in the recess 22. It will not start until after. As a result, the flow rate of the liquid resin that goes around the peripheral portion of the semiconductor device 11 can be reliably reduced, so that void generation at the time of filling the liquid resin can be prevented.

  At this time, as shown in FIG. 4A, the shape of the recess 22 has a length parallel to the side in the vicinity of the liquid resin discharge position 23 with respect to the outer peripheral edge of the semiconductor device 11, and parallel to the side continuous with the side. It is desirable to keep the length large. That is, it is desirable that the recess 22 has a length in the left-right direction in FIG. 4A larger than a length in the vertical direction in FIG. 4A. By doing so, the start of the flow of the liquid resin that goes around the periphery of the semiconductor device 11 can be surely delayed.

  In the third embodiment, the concave portion 22 is provided only at the liquid resin discharge position 23. However, the concave portion may be provided at the position described in the first and second embodiments. This is more desirable because the time required for the liquid resin to surround the semiconductor device 11 becomes longer.

Example 4
FIG. 5A shows a schematic top view of the mounting structure of the semiconductor device according to the fourth embodiment of the present invention. 5B is a schematic cross-sectional view taken along line VB-VB in FIG. 5A. 5A and 5B, the same components as those in the first embodiment shown in FIGS. 1A and 1B are denoted by the same reference numerals as those in FIGS. 1A and 1B. Moreover, the arrow of FIG. 5B has shown the discharge direction to the liquid resin discharge position 23 of liquid resin.

  The fourth embodiment is different from the first embodiment only in that a mounting substrate 313 having no main surface formed with a recess is used.

  Although the organic resin film 15 is formed on the mounting substrate 313, the semiconductor device mounting portion 14 is provided with a normal main opening 10 having substantially the same shape as the semiconductor device 11 to be mounted. In particular, as in recent years, when the terminal pitch interval is narrowed and a severe situation regarding moisture resistance reliability is considered, the gap between the outer periphery of the semiconductor device 11 and the main opening 25 is narrow, for example, only about 100 μm. . In the fourth embodiment, in addition to the main opening 10, two additional openings 20 are formed at predetermined positions. The end of the additional opening 20 on the semiconductor device 11 side is located closer to the mounting substrate 313 than the main surface 11 a of the semiconductor device 11.

  The role of the additional opening 20 will be described below. The additional opening 20 is formed in addition to the normal main opening 10. Considering that after forming a flip chip mounting structure by a normal method, a liquid resin is dropped at the liquid resin discharge position 23 to fill the gap between the semiconductor device and the mounting substrate with the liquid resin. As described above, the flow of the liquid resin that travels through the gap between the semiconductor device 11 and the mounting substrate and the flow of the liquid resin that goes around the periphery of the semiconductor device 11 occur.

  As shown in FIG. 5B, the liquid resin that wraps around the peripheral portion of the semiconductor device 11 flows due to capillary action in a very narrow gap D between the outer peripheral edge of the semiconductor device 11 and the main opening 10 of the organic resin film 15. The flow rate is fast. If there is an additional opening 20 of the organic resin film 15 in the middle of the flow of the liquid resin, the space between the outer peripheral edge of the semiconductor device 11 and the organic resin film 15 is widened only at a position where the additional opening 20 is present. In addition, since the liquid resin that goes around the peripheral portion of the semiconductor device 11 cannot advance beyond the space in the additional opening 20, it takes a long time to surround the semiconductor device 11. As a result, generation of voids in the liquid resin can be suppressed.

  Note that the additional opening 20 is provided in any one of two sides parallel to the vertical direction in FIG. 5A with respect to the outer peripheral edge of the semiconductor device 11 and a side near the liquid resin discharge position 23 with respect to the outer peripheral edge of the semiconductor device 11. It is desirable to form them adjacent to each other. Further, as in the third embodiment, the additional opening 20 may include the liquid resin discharge position 23. That is, the additional opening 20 may overlap the liquid resin discharge position 23.

  In order to obtain the structure shown in FIG. 5, no additional steps are required. It is only necessary to change the opening shape of the organic resin film when the mounting substrate 313 is manufactured. Therefore, voids in the underfill part can be prevented without causing any trouble.

  When a material excellent in wettability with a liquid resin, for example, a polar hydrogenated oligomer resin, is applied to the side surface of the additional opening 20 or the main surface of the mounting substrate 313 exposed from the additional opening 20, the additional opening 20. The liquid resin can be reliably guided into the inside, and the speed of the liquid resin that goes around the periphery of the semiconductor device 11 can be reduced.

  Further, a metal land (not shown) may be formed on the main surface of the mounting substrate 313 exposed from the additional opening 20. The metal land is formed of the same configuration as that of the pad electrode 16, for example, a material, and is formed with a predetermined distance from the pad electrode 16 and the substrate wiring 18. Due to the presence of the metal land, the liquid resin is reliably guided into the additional opening 20 without depending on the wettability between the insulating material of the mounting substrate 313 and the liquid resin, and the space in the additional opening 20 is Can be filled with liquid resin.

  When forming the metal land, no additional process is required. That is, it is only necessary to leave the metal land portion when patterning the pad electrode 16 and the substrate wiring 18 on the main surface of the mounting substrate 313. By only this design change, voids in the underfill portion obtained by curing the liquid resin can be suppressed.

  In particular, it is necessary to maintain moisture-resistant insulation reliability even in a situation where the terminal pitch interval has been narrowed in recent years. For this reason, the fourth embodiment employs a structure in which the organic resin film 15 is formed so that the opening edge of the main opening 10 of the organic resin film 15 is quite close to the outer peripheral edge of the semiconductor device 11. Even if this structure is adopted, void generation can be suppressed.

  According to the semiconductor device mounting structure of the present invention having the first to fourth embodiments, underfill without voids can be achieved in the flip chip mounting structure. As a result, it is possible to obtain a semiconductor device mounting structure that is highly reliable and suitable for application to light and thin electronic devices.

  In addition, the above mounting structure is considerably close to the outer periphery of the semiconductor device in order to improve the insulation reliability by crushing bump electrodes like the flip chip connection method by ultrasonic bonding and narrowing the connection part interval. This is also effective for a structure in which the organic resin film is formed up to the above position.

  Moreover, in the said Examples 1-4, although the liquid resin discharge position 23 was located in the approximate center vicinity of the one side of the outer periphery of the semiconductor device 11, as shown in FIG. You may locate in the one end part vicinity.

  In the case of FIG. 8, the liquid resin that flows along the outer peripheral edge of the semiconductor device 11 includes a resin that flows in the arrow R direction and a resin that flows in the arrow L direction. Here, a point where the distance traveled by the liquid resin flowing in the direction of the arrow R coincides with the distance traveled by the liquid resin flowing in the direction of the arrow L is defined as the farthest peripheral point P1. That is, a point advanced from the liquid resin discharge position 23 by one-half of the entire circumference of the outer peripheral edge along the outer peripheral edge of the semiconductor device 11 is defined as the outermost path P1. A point farthest from the liquid resin discharge position 23 by a linear distance with respect to the outer peripheral edge of the semiconductor device 11 is defined as a distance farthest point P2.

  When the outermost path P1 and the farthest distance P2 are defined in this way, the path from the liquid resin discharge position 23 along the arrow R to the outermost path P1 and the liquid resin discharge position 23 from the arrow L It is desirable that a recess and an opening similar to the recess 22 and the additional opening 20 are provided in at least one of the paths that reach the farthest distance point P2 along the line.

  Further, it is more preferable that the recess and the opening are adjacent to each side other than the side passing through the region near the outermost path P1.

1A is a schematic top view of a mounting structure of a semiconductor device according to Embodiment 1 of the present invention. 1B is a schematic cross-sectional view taken along line IB-IB in FIG. 1A. FIG. 1A is a schematic top view for explaining the flow of the liquid resin in the semiconductor device mounting structure of the first embodiment. 2B is a schematic cross-sectional view taken along the line IIB-IIB in FIG. 2A. FIG. 3 is a schematic cross-sectional view of a semiconductor device mounting structure according to a third embodiment of the present invention. FIG. 4A is a schematic top view of the mounting structure of the semiconductor device according to the third embodiment of the present invention. 4B is a schematic cross-sectional view taken along the line IVB-IVB in FIG. 4A. FIG. 5A is a schematic top view of a semiconductor device mounting structure according to a fourth embodiment of the present invention. 5B is a schematic cross-sectional view taken along line VB-VB in FIG. 5A. FIG. 6 is a schematic cross-sectional view of a conventional semiconductor device mounting structure. FIG. 7 is a schematic cross-sectional view of another conventional semiconductor device mounting structure. FIG. 8 is a diagram for explaining a mounting structure of a semiconductor device according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Main opening part 11 Semiconductor device 12 Bump electrode 13,213,313 Mounting board 14 Semiconductor device mounting part 15 Organic resin film 16 Pad electrode 17 Connection part 18 Substrate wiring 19 Via wiring 20 Additional opening part 21 Underfill part 22 Recessed part 23 Liquid Resin discharge position 41, 42 Insulating layer 43 Wiring 44 Metal land

Claims (9)

A semiconductor device in which a plurality of bump electrodes are arranged on the main surface;
A mounting substrate having a semiconductor device mounting portion on which the semiconductor device is mounted, and a plurality of pad electrodes formed corresponding to the positions of the plurality of bump electrodes on the surface of the semiconductor device mounting portion on the semiconductor device side; ,
With
In the mounting structure of the semiconductor device in which the plurality of bump electrodes and the plurality of pad electrodes are connected by flip chip bonding, and a resin is filled between the semiconductor device and the mounting substrate.
A recess that is formed around the semiconductor device mounting portion and is located in the vicinity of the outer periphery of the semiconductor device, and that can reduce the flow rate of the resin flowing around the semiconductor device,
The semiconductor device mounting structure, wherein an end of the concave portion on the semiconductor device side is located on the mounting substrate side with respect to a main surface of the semiconductor device. In the mounting structure of the semiconductor device according to claim 1,
In order to fill the resin between the semiconductor device and the mounting substrate, when dropping a liquid resin to the dropping position around the semiconductor device,
A point that is one half of the entire circumference of the outer peripheral edge along the outer peripheral edge of the semiconductor device from the dropping position is the farthest outer peripheral path, and a linear distance from the dropping position with respect to the outer peripheral edge of the semiconductor device. When the farthest point is the farthest distance,
A path reaching the farthest outer peripheral path from the dropping position along the outer peripheral edge of the semiconductor device, and a farthest distance from the dropping position along the outer peripheral edge of the semiconductor device. A mounting structure for a semiconductor device, wherein the recess is formed in at least one of the path and the path. In the mounting structure of the semiconductor device according to claim 2,
The semiconductor device mounting structure, wherein the recess includes the dropping position. In the mounting structure of the semiconductor device according to claim 2,
The semiconductor device mounting structure, wherein the recess is adjacent to a side other than a side passing through a region near the farthest outer peripheral path with respect to an outer peripheral edge of the semiconductor device mounting portion. In the mounting structure of the semiconductor device according to claim 4,
2. A semiconductor device mounting structure, wherein there are two sides other than a side passing through a region near the farthest outer peripheral path, and the recess is adjacent to at least one of the two sides. In the mounting structure of the semiconductor device according to any one of claims 1 to 5,
A mounting structure of a semiconductor device, wherein a bottom surface of the recess is formed of a material excellent in wettability with the resin. In the mounting structure of the semiconductor device according to any one of claims 1 to 5,
The mounting structure of a semiconductor device, wherein the bottom surface of the recess includes the same metal as the metal included in the pad electrode. In the mounting structure of the semiconductor device according to any one of claims 1 to 5,
On the mounting substrate, an organic resin film is formed so as to surround the semiconductor device,
An organic resin film formed so as to surround the semiconductor device and having a main opening and an additional opening adjacent to the main opening,
The main opening overlaps the semiconductor device mounting portion and is approximately the same size as the semiconductor device,
The semiconductor device mounting structure, wherein the recess includes the additional opening. The semiconductor device mounting structure according to claim 8,
The substrate wiring drawn from the pad electrode is formed outside the region where the additional opening is formed,
The mounting structure of a semiconductor device, wherein the additional opening has a metal pattern made of the same kind of metal as the material of the substrate wiring at the bottom.

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