JP2009188260A - Semiconductor device and mounting substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device in which even if the number of bumps and electrodes are increased in a flip chip and a backside-mounting semiconductor chip due to enhancement of functions and the size is made smaller, when mounting the flip chip and the backside-mounting semiconductor chip on a mounting substrate, they can be easily aligned with electrodes on the side of the mounting substrate. <P>SOLUTION: A solder ball as a second electrode 22A is provided in a portion corresponding to the side face of a semiconductor chip 12 to be mounted on a mounting substrate 10. Since the solder ball falls toward the inside of a chip, the position of the semiconductor chip can be controlled. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flip-mounted semiconductor device and a mounting substrate for flip mounting.

  Generally, a semiconductor device is mounted on a lead frame and sealed with resin. That is, the chip is fixed to the island, the lead and the chip are connected by a wire, and the whole is sealed with resin. In this semiconductor device, since the lead protrudes from the package, and the wire further protrudes upward and draws a curve, the thickness of the resin is increased, and the overall size is increased. Further, when this semiconductor device is provided on a mounting substrate such as a printed circuit board, it occupies a large area and is difficult to downsize.

  However, with light and thin trends, packages or modules having various structures for semiconductor devices have been born. In FIG. 4, the lead frame described above is omitted, and a bare chip 2 is mounted on a mounting substrate 1. This is because the external leads do not extend from the package, and accordingly, the chip mounting area can be reduced and the thickness of the entire module 3 can be reduced.

  On the other hand, FIG. 5 shows a face-down type semiconductor chip 4 mounted face-down. In this case, unlike FIG. 4, the thickness of the module 6 is further reduced because there is no curved portion to the upper part of the fine metal wire 5.

  However, as shown in FIG. 5, the bumps 6 of the semiconductor chip 4 are increased to 500 pins and 1000 pins as the LSI becomes more sophisticated. Therefore, the size of this bump is getting smaller year by year. Therefore, as the size of the bump 6 is reduced, the size of the pad 8 of the mounting substrate 7 is also reduced.

  Therefore, as shown in FIG. 5, the alignment of the bump 6 and the pad 8 becomes difficult and sometimes deviates.

  As a matter of course, recently, the chip mounter is used, but there is a case where it is still shifted. Therefore, as the size of bumps and pads becomes smaller, a chip mounter with high accuracy is required, but the mounter naturally becomes expensive.

  The present invention has been developed to solve these problems.

The present invention has been made in view of the aforementioned problems,
First, the mounting substrate includes a plurality of first electrodes provided corresponding to a plurality of bumps provided on the semiconductor chip or the semiconductor package, and corners of the semiconductor chip or the semiconductor package. The problem is solved by comprising a supporting member provided on at least two sides and a means provided on the supporting member and serving as a guide for regulating the position of the side of the semiconductor chip or the semiconductor package.

  According to a third aspect of the present invention, the means serving as the guide is solved by solder or conductive paste raised by surface tension.

  According to the third aspect of the present invention, since the solder forms a substantially hemisphere as an example, if the side of the chip hits a portion inclined from the head of the solder, self-alignment is performed by the weight of the chip.

  As shown in FIG. 1B, when a solder ball is applied to at least two side surfaces of the semiconductor chip constituting the corner, the semiconductor chip is cut by positioning. Alternatively, the movement of the semiconductor chip can be stopped mechanically. Therefore, alignment can be easily performed by human hands or by a simple mounter with low precision.

Therefore, even in a manufacturing company that cannot make capital investment, in such a semiconductor device having at least a mounting substrate whose surface is insulated and a flip chip type semiconductor chip or a BGA type semiconductor package flip mounted on the mounting substrate. ,
Further, the chip can be positioned by providing a conductive pattern substantially having its center provided at the corner of the semiconductor chip or semiconductor package.

  Hereinafter, before describing embodiments of the present invention, an outline of the present invention will be described.

  Along with lightness and thinness in recent years, semiconductor chips have become thinner and smaller, and the number of pads has become extremely large due to higher functionality of semiconductor ICs. Therefore, the size of the pad has been smaller than before. In order to reduce the thickness as a molded package or as an unmolded module, the semiconductor chip has been apt to be mounted by flip chip that does not employ wire bonding, that is, face-down (hereinafter referred to as FD). Here, the face-down type semiconductor chip is a type in which a bump is provided on the upper layer of the semiconductor chip electrode, and further, a rewiring is provided on the electrode of the semiconductor chip, and an electrode is provided at the tip of the rewiring. Bumps are provided on the top. For example, semiconductor chips called WLP and W-CSP are also applicable.

  In this FD, it is necessary to align the bumps of the semiconductor chip and the electrodes of the mounting substrate. Of course, if it is mounted with an expensive chip mounter, it is possible to align with high accuracy, but it is sufficient if there is a device, but in general factories, it is difficult to adopt it considering the capital investment cost, and it is necessary to consider some other method There is.

  In the present invention, the chip has a rectangular parallelepiped, that is, a mounting surface (surface on which the bumps of the chip are attached), a back surface opposite to the mounting surface, and four side surfaces connecting the periphery of the mounting surface and the back surface. From a perspective, it is a rectangle. Then, in this rectangle, if a means for position regulation is provided on two sides forming at least one corner (corner) or two sides corresponding to the two sides, the chip is This position restricting means enables highly accurate mounting. In the present invention, the position regulating means is realized by a brazing material such as solder, a conductive paste such as Ag paste or an adhesive, and the like, and the surface is curved on the mounting substrate by surface tension. It is realized by means by mechanical contact like a ball bump electrode.

  For example, when solder melts into a circular Cu pad, a curved surface can be formed. In addition, the conductive paste and the adhesive have a fluidity in the resin before curing, and if the resin is solidified by using a ring-shaped resin flow stopper or the like, the surface also exhibits a curvature. The shape of the pad is not limited to a circle, and may be a polygon such as a triangle or a square. This can be easily seen by melting the solder. Further, the ball bump can be realized by adopting, for example, a wire bonding apparatus. When the tip of the fine metal wire is melted with a spark or torch, a ball can be formed at the tip of the fine metal wire. By bonding this to the mounting substrate and tearing it, a substantially semicircular curved surface can be formed.

  For example, if the side surface of the semiconductor chip or the corner portion under the chip is brought into contact with somewhere in the curved portion, the position of the semiconductor chip can be regulated. Also, if the hemisphere is placed on the four sides of the semiconductor chip and the lower surface of the hemisphere is the original position regulating part, the operator can place it between them with tweezers, and the side of the chip or The corner hits and the chip slides due to its own weight, and the bump of the chip can be accurately regulated to the electrode on the mounting substrate side.

  Alternatively, the mounting substrate side may be covered with an insulating resin or a conductive material and patterned by lithography to form a three-dimensional pattern. Specifically, it may be a column or a cone whose bottom surface forms a convex portion with a triangle, square / pentagon, hexagon, circle, or the like. For example, if the semiconductor chip is brought into contact with a side surface of a cone which is one of cones, the position can be regulated. Since the side surface of the pyramid is lowered like a slide, the cone can be lowered by its own weight by contacting the side surface or the lower corner of the chip, and the position can be regulated.

  Now, the first embodiment will be described with reference to FIG. Reference numeral 10 denotes a mounting board, for example, a printed circuit board (including a rigid board made of a resin material such as an epoxy material, a flexible sheet made of polyimide, etc., and the resin material is not limited to this), a ceramic board, and an insulating surface. A processed metal substrate mainly made of Cu or Al, a semiconductor chip formed by PN bonding, a substrate made of Si having at least a surface insulated, for example, an Si interposer.

  Printed boards and ceramic boards include a module type in which the board itself is made of an insulating material, and an element is mounted on at least a conductive pattern formed on the surface. Further, there is a package type in which an element is molded based on the board. . Therefore, in both cases, this positioning means can be adopted. In addition, this type of substrate may be a multilayer substrate formed of two layers, four layers, six layers,.

  Further, the metal substrate itself is made of a conductive material, and at least the surface is insulated for the insulation treatment with the conductive pattern formed on the surface. Some are anodized or coated with an insulating resin. Furthermore, an insulating resin may be formed on the anodic oxide film. The conductive pattern may be a multilayer.

  In some cases, the semiconductor chip is currently mounted on the first semiconductor chip by a flip chip with a second chip smaller in size than the semiconductor chip. Also in this case, there are a type that is not transfer molded and a type that is transfer molded. In this case, the first semiconductor chip corresponds to a mounting substrate and is called an MCP or the like. The present invention can also be applied to this case.

  The same applies to the Si interposer. A general Si interposer is used as a mounting substrate in the same manner as a printed circuit board, and since it is a Si chip, it has a thermal expansion coefficient α that is effective when mounting a thin flip chip.

  The mounting substrate 10 shown in FIG. 1 shows all these types. The uppermost conductive pattern 11 is formed on the outermost surface. The conductive pattern 11 includes an electrode and a wiring that is integrated with the electrode and contributes to electrical connection. If necessary, there is a lead attachment electrode. Since the face-down type chip 12 is mounted on the electrode, the first electrode 13 is provided corresponding to the bump electrode BP of the chip 12. If necessary, an electrode for mounting the chip component 14 as a passive element is also provided.

  Further, if the back surface of the mounting substrate 10 is placed on a large printed circuit board, an electrode for bump connection may be formed.

  The chip 12 is a rectangular parallelepiped, and a surface on which the bumps 14 are provided is a mounting surface, and a surface facing the surface is a back surface 15. There are four side surfaces around the mounting surface and the back surface 15. FIG. 1 (C) is the drawing, and the semiconductor element 16 is naturally formed in the Si substrate 17 by PN junction. An electrode 18 is provided via an insulating layer formed on the surface and a contact formed on the insulating layer. Here, although it is a single layer metal, a multilayer metal may be sufficient. Bumps BP are provided on the uppermost metal on the mounting surface side. Here, the solder bumps are used, but bumps made of a conductive material such as Au or Cu may be used. In some cases, a rewiring is formed on the uppermost metal by, for example, plating, and a bump electrode is formed at the end of the rewiring.

  The present invention is characterized by the support member S that abuts the side surfaces 20A to 20D of the chip 12 or the corners 21A to 21D below the side surface and regulates the position of the chip 12.

  Specifically, on the outermost surface of the mounting substrate 10, there are second electrodes 22 </ b> A to 22 </ b> C such as rectangles and circles made of Cu, for example, and brazing materials 23 </ b> A to 23 </ b> D are provided thereon. For example, if the second electrode is a circle, the brazing material has a hemispherical shape because it is solidified after melting at one end. Even if it is a square, its surface exhibits a three-dimensional structure close to a hemisphere, even if it is not a hemisphere, due to surface tension. Furthermore, even if the second electrode 22 is rectangular, a solder resist 24 (passivation film in the case of a Si chip or Si interposer) is formed thereon as shown in FIG. You may form so that the center of may open. The opening is preferably a circle, but may be a square, five strokes, hexagon,... In the case of solder, the substantial hemispherical shape shown in FIG. The reason why the substantial hemisphere is used here is that the curved surface is drawn by the surface tension regardless of the shape of the wetted portion of the solder as the base.

  If at least one brazing material 23 as the support member S is originally formed on the four sides of the chip 12, the position can be easily regulated. For example, the position is regulated by its own weight simply by inserting a flip chip between the support members S of a hemisphere with tweezers. Actually, the corner portion 21 of the chip hits the curved surface, and the curved surface curves downward toward the inside of the chip, so that the position is regulated while sliding like a slide.

  Further, at least one support member S may be provided at each of the positions corresponding to the side surfaces 20A (21A) and 20B (21B) constituting the corner portion in plan view. Further, as shown in FIG. 3, at least one of them may be provided over three sides. In the case of these two cases, since they are not arranged on the four sides, for example, in FIG. However, if the right side is restricted by mechanical means, the position of the flip chip can be restricted.

  Further, the bump BP must be in contact with the first electrode 13 of the mounting substrate 10. However, if it is only slightly floating, it can be connected by pressure. When the solder melts, the volume expands or hangs down, so that the first electrode 13 can be wetted and connected. However, if there is a large gap, connection is difficult, but normally, 100 to 200 g per bump can be pressurized and brought into contact. This is determined by the thickness of the mounting substrate, chip outer shape accuracy, bump position accuracy and size, and support member size and position accuracy. For example, even if the position accuracy of the second electrode is poor, if the position accuracy of the opening of the solder resist 24 and the amount of solder are formed with a certain degree of accuracy, the bump BP and the electrode on the mounting board side are electrically connected to each other. Can connect.

  In a simple experiment, even if the inventor mounted a flip chip having 100 bumps and a chip size of 5 mm × 5 mm with tweezers, it could be easily connected. This can be connected without using a high-precision and expensive chip mounter, and it can be seen that there is a significant merit in terms of manufacturing cost.

  Further, the bump BP and the first electrode 13 can be aligned by the guide S, and when the solder is melted, the chip itself is lightweight due to the surface tension of the solder, and is self-aligned. Even if this self-alignment is not expected, if the solder is overheated while being fixed through an underfill, the solder is melted and electrical connection becomes possible.

Although the flip chip 12 has been described in FIG. 1, self-alignment is possible in the same manner even with a surface mount type package 12A as shown in FIG. 1D. This is a BGA type package using a printed circuit board or a flexible sheet. A chip is mounted on the package substrate 30 and transfer molded, and bumps are formed on the back surface of the package substrate in a matrix or in a ring shape from the outside to the inside.
The current mainstream packages are as follows. Prepare a printed circuit board in which conductive patterns that are element arrangement areas are repeatedly formed in a matrix, mount at least one semiconductor chip in each element arrangement area, transfer mold the whole, and element arrangement area There is a MAP (matrix, array, package) type that is separated by dicing every time.

  Generally, a face-down type semiconductor chip is realized by the following two methods. One is to press-contact the bumps on the chip side and the first electrode, and then flow an underfill material into the gap between the chip and the mounting substrate to cure. The second is to drop an underfill material on the mounting substrate side in advance, press the chip, and harden.

  If the melting points of the guide S and the solder bump are close to each other, the solder on the guide side may melt and not be a guide. In this case, the latter method is preferable. When the position is regulated, pressure welding is performed, the semiconductor chip is fixed, an underfill is inserted, and solidified at 120 to 130 degrees. After the chip is further fixed, the solder is melted at a temperature of about 270 degrees. And good.

  If the solder of the guide S has a high melting point and a large difference in melting point, there is no such problem.

  Next, description will be made with reference to FIG. In FIG. 2, an underfill material 30 is provided between the mounting surface of the flip-chip mounted chip 12 and the mounting substrate 10. The filler is mixed here due to the difference in coefficient of thermal expansion. 2A shows a type using a brazing material, and FIG. 2B uses a metal ball.

  This metal ball can be formed at the tip of the bonding tool through which the fine metal wire passes by the method described above. If ball bonding is performed to the second electrode 22 of the mounting substrate 10, it is provided by position restricting means that exhibits a curved surface although it cannot be said to be a hemisphere. Since this bonding does not require an electrical connection, the bonding pressure can be reduced, and it can be closer to a sphere. The cutting of the fine metal wire can be realized by holding the fine metal wire with a clamper provided in the bonding tool and pulling it upward.

  In FIG. 2, the solder and the metal ball have been described, but instead of these, the material, conductive paste, and fluid resin described in the first half may be applied and solidified. Further, as shown in FIG. 1A, the second electrode 22 may be arranged in an island shape, or may be integrated with the wiring as in the right side. The former is electrically floating, while the latter is electrically connected. For example, if the chip falls to GND and this wiring is also GND, no problem occurs.

  If the film is pasted on the back surface 15 of the chip, the second electrode to which a signal is applied is OK because it is insulated.

  FIG. 3 shows a Si interposer or Si chip 40, and a flip chip 12 mounted thereon. Reference numeral 41 denotes a bonding pad in the case of a Si chip, a lead attachment pad in the case of an interposer, or a through hole (through electrode) necessary for connection to the back electrode if a back electrode is provided. ).

  Moreover, as can be said in all the embodiments, a device in which a through electrode is formed instead of a flip chip may be used. Here, it is referred to as a back-mounted semiconductor chip. Through electrodes, also referred to as through silicon vias, are arbitrarily formed on the semiconductor chip, and electrical signals generated on the electrodes on the chip surface can be generated on the electrodes on the back surface of the chip. That is, a part or all of the electrodes can be arranged on the back surface of the chip, the fine metal wires can be omitted or eliminated, and the thickness of the apparatus can be reduced.

  As shown in the drawing, if the support means S is formed on the second electrode by the method described so far, the position of the chip placed thereon can be regulated.

  Next, FIG. 6 will be described. This is an embedded substrate 50, in which a semiconductor chip 51 is built in the substrate 50. Of course, since it is a substrate, another semiconductor chip is mounted on the outermost electrode 52. Of course, position regulating means may be provided on the surface as in the embodiment of FIG. Here, the position regulating means S is provided in the substrate 50. In the substrate, at least one conductive pattern 54, 55 is formed on both sides of the core layer 53, that is, a two-layer wiring substrate is further formed with an insulating layer 56 on both sides, and further an electrode 52 is formed on the outermost surface 6 It is a layer substrate. However, it may be a 4-layer or 8-layer or 10-layer substrate. Moreover, the board | substrate which laminates | stacks an insulating layer and a conductive pattern in order from the bottom with a clad | crud without using a core layer may be used.

  Specifically, an electrode corresponding to the bump of the face-down type chip 51 and the second electrode 60 for forming the support regulating means S are exposed through the insulating layer of the multilayer substrate, and formed in advance. In other words, the flip chip is positioned by the regulating means S formed after being punched.

  FIG. 7 shows an example in which an L-shaped second electrode or a conductive material (for example, Cu) is provided on the mounting substrate in place of the guide S in FIG. 1, and both the chip position recognition and the guide S are provided. It is. A solder resist is provided and solder is applied so that one of the two rectangles constituting L is exposed. Then, the solder will be curved. Therefore, the position of the chip can be regulated. If the corners of the chip coincide with the inner corners of the L shape, it can be seen that the chips are arranged without any deviation.

  Returning to FIG. 1, the pattern M provided on the mounting board is used for recognizing the position of the chip. This pattern only needs to recognize the center, and may be a polygon such as a square other than a circle. For example, in the case of a circle, if the corner of the chip is located at a portion corresponding to the midpoint of the circle, it can be determined that there is no deviation.

  FIG. 8 shows a POP (Package On Package). A BGA type package or face-down type chip is mounted on the main substrate 70, and a large solder ball is provided as an external electrode on the back surface of the mounting substrate 70. Alternatively, a BGA type package is mounted.

  Therefore, the guide S is provided in a portion corresponding to the side of each chip. This can also be realized by the shape and method described so far.

  As described above, the support restricting means can be easily provided, and the flip chip and back surface mounting type packages can be aligned by a simple method. In addition, as can be said in all the embodiments, when the solder ball is formed on the back surface of the mounting substrate, the solder ball as the position regulating means melts when the solder ball is melted. It is preferable to employ one having a melting temperature higher than that of the solder ball.

It is a figure which shows the circuit module of this invention. It is a figure which shows the circuit module of this invention. It is a perspective view of the circuit module of the present invention. It is a figure which shows the conventional circuit module. It is a figure which shows the conventional circuit module. It is a figure which shows the circuit board of this invention. It is a figure which shows the circuit module of this invention. It is the figure which applied this invention to POP.

Explanation of symbols

10: Mounting substrate 11: Conductive pattern 12: Flip chip (or back surface mounting type semiconductor chip)
13: First electrode 15: Back surface 20: Side surface 21: Corner portion 22: Second electrode S: Support member BP: Bump

Claims (17)

In a semiconductor device having at least a mounting substrate whose surface is insulated, a face-down type semiconductor chip mounted on the mounting substrate, a back surface mounting type semiconductor chip employing a through electrode, or a BGA type semiconductor package ,
The mounting substrate includes a plurality of first electrodes provided corresponding to a plurality of bumps provided on the semiconductor chip or the semiconductor package, and at least two sides constituting a corner of the semiconductor chip or the semiconductor package. A semiconductor device comprising: a support member provided on a side; and a means provided on the support member and serving as a guide for regulating a position of a side of the semiconductor chip or the semiconductor package. The semiconductor device according to claim 1, wherein the guide means has an inclination or a curve toward a mounting region of the semiconductor chip or the semiconductor package. The semiconductor device according to claim 2, wherein the means serving as the guide is solder or conductive paste raised by surface tension. The semiconductor device according to claim 2, wherein a ball made of metal is mechanically bonded to the support member provided on the mounting substrate. The semiconductor device according to claim 3, wherein the support member is made of a conductive coating, and is provided on the conductive coating, and a film is provided on which the conductive coating is exposed in a circle, a square, or an L shape. The semiconductor device according to claim 1, wherein the mounting substrate is a metal substrate, a printed substrate, a ceramic substrate, a flexible sheet, a Si device, or a Si substrate. A mounting substrate for mounting a face-down type semiconductor chip or a BGA type semiconductor package,
The mounting substrate includes a plurality of first electrodes provided corresponding to a plurality of bumps provided on the semiconductor chip or the semiconductor package, and at least two sides constituting a corner of the semiconductor chip or the semiconductor package. A mounting substrate comprising: a supporting member provided on a side; and means provided on the supporting member and serving as a guide for a bump of the semiconductor chip or the semiconductor package and a first electrode of the mounting substrate. The mounting substrate according to claim 7, wherein the means serving as the guide has an inclination or a curve toward a mounting region of the semiconductor chip or the semiconductor package. The mounting substrate according to claim 8, wherein the support member is solder or conductive paste raised by surface tension. The mounting board according to claim 8, wherein a ball made of metal is mechanically bonded to the support member. The mounting substrate according to claim 9, wherein the support member is made of a conductive coating, is provided on the conductive coating, and is provided with a film that exposes the conductive coating in a circle, square, or L shape. The semiconductor device according to claim 7, wherein the mounting substrate is a metal substrate, a printed circuit board, a ceramic substrate, a flexible sheet, a Si device, or a Si substrate. 13. The multilayer substrate in which a wiring layer and an insulating layer are repeatedly stacked on at least one surface of the mounting substrate, and the first electrode, the support member, and the semiconductor chip are embedded in the multilayer substrate. The mounting board described. In a semiconductor device having at least a mounting substrate whose surface is insulated and a face-down type semiconductor chip or a BGA type semiconductor package flip-mounted on the mounting substrate.
The mounting substrate includes a plurality of first electrodes provided corresponding to a plurality of bumps provided on the semiconductor chip or the semiconductor package, and a center substantially provided at a corner of the semiconductor chip or the semiconductor package. A semiconductor device characterized in that a conductive pattern is provided. A mounting substrate for flip mounting of a flip chip type semiconductor chip or a BGA type semiconductor package,
The mounting substrate includes a plurality of first electrodes provided corresponding to a plurality of bumps provided on the semiconductor chip or the semiconductor package, and a center substantially provided at a corner of the semiconductor chip or the semiconductor package. A mounting board characterized in that a conductive pattern is provided. In a semiconductor device having at least a mounting substrate whose surface is insulated and a face-down type semiconductor chip or a BGA type semiconductor package flip-mounted on the mounting substrate.
The mounting substrate has a plurality of first electrodes provided corresponding to a plurality of bumps provided on the semiconductor chip or the semiconductor package, and a bent portion is provided at a corner of the semiconductor chip or the semiconductor package. A semiconductor device characterized in that an L-shaped conductive pattern is provided. A mounting substrate for flip mounting of a flip chip type semiconductor chip or a BGA type semiconductor package,
The mounting substrate has a plurality of first electrodes provided corresponding to a plurality of bumps provided on the semiconductor chip or the semiconductor package, and a bent portion is provided at a corner of the semiconductor chip or the semiconductor package. A mounting board characterized in that an L-shaped conductive pattern is provided.

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