JP4531073B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device, and relates to a CSP type semiconductor device using a Cu frame such as a lead frame.

  Although the semiconductor device is a well-known matter, an IC is formed in a matrix form in the state of a wafer, a dicing line portion is provided in a lattice shape surrounding the IC, and dicing is individually performed along the dicing line portion. The semiconductor device (semiconductor chip) is formed separately. Then, it is mounted on a lead frame, and the IC and the lead are wire-bonded and packaged.

  However, with the miniaturization of cellular phones and digital cameras, semiconductor devices are increasingly required to be miniaturized. Recently, CSPs and wafer scale CSPs have been developed as technologies that approach the chip size without limit.

  Examples of CSPs in which a semiconductor chip is mounted on a substrate and the chip size is reduced by using wire bonding include Japanese Patent Laid-Open Nos. 10-92979 and 58-201347.

  These technologies employ a ceramic substrate and reduce the chip size in order to minimize the extension length of the lead frame beyond the metal thin wire while adopting highly reliable metal thin wire connection as the connection. is there.

  FIG. 7 and FIG. 8 explain the outline. In FIG. 7, a semiconductor chip 2 is fixed to a ceramic substrate 1, and a bonding pad of the semiconductor chip 2 and a pad electrode 3 on the ceramic substrate 1 are connected via a fine metal wire. The ceramic substrate 1 is provided with through holes and multilayer wiring as required, and a pad 4 to be soldered to the mounting substrate via a brazing material is provided on the back surface of the ceramic substrate 1. The bonding pads of the semiconductor chip 2 are electrically connected to the pads 4 on the back surface through fine metal wires, pad electrodes 3, through holes, or multilayer wiring.

Then, as shown in FIG. 8, the resin sealing body 5 is formed and diced at a portion indicated by an arrow. This dicing may be performed on either the back side or the front side of the ceramic substrate. Further, the ceramic substrate may be provided with a split groove, and dicing to the front of the ceramic substrate, and the ceramic substrate may be broken through the split groove.
JP-A-10-92979 JP-A-58-201347

  Unlike the package employing the lead frame, the structure described above can be made smaller because the lead is not taken into the package and the pad electrode is extremely small.

  However, the ceramic substrate 1 has a problem in that the cost increases because through holes and multilayer wiring are provided, and the pad electrode 3 and the pad 4 require Au plating.

  Further, the electrodes of the ceramic substrate 1 are generally printed, and the connection with the mounting substrate has a problem that the connection strength cannot be increased so much due to the thickness of the printed electrodes.

  The present invention solves the above problems.

  In view of the above, a semiconductor device according to the present invention includes a semiconductor chip, a resin sealing body that seals the semiconductor chip, and a connection piece and a fixing piece that are exposed on the back surface of the resin sealing body. The connection piece is electrically connected to the semiconductor chip, and the fixed piece is electrically insulated from the semiconductor chip and formed at a corner portion on the back surface.

  According to the present invention, the connection piece can be individually separated by adopting the frame made of metal and removing the coupling body which is one component of the frame after sealing. Further, the size of the connection piece may be a size that can connect the thin metal wires, and the size of the semiconductor device as a whole can be reduced.

  Further, since the frame is embedded in the resin and the connection piece is exposed on the back surface of the sealing body, this can be realized without employing a ceramic substrate as in the prior art. Therefore, the cost can be reduced as compared with the conventional semiconductor device employing the ceramic substrate.

  In addition, a chip size semiconductor device can be realized in the type that faces down to the frame.

  Further, since the coupling body is removed by dicing, the side surface of the connection piece exposed in this region can be used as a connection region for the brazing material, and the connection strength with the mounting substrate can be enhanced.

  Moreover, since the connection body can be easily removed by dicing, the process can be simplified.

  Next, a first embodiment of the present invention will be described with reference to FIGS. The component shown in FIG. 1 is a general lead frame, which is a frame made of a metal material having a lead frame thickness (for example, Cu as a main material). This may be a foil. In this case, the flexible sheet may be sandwiched in consideration of handling. This will be described later.

  First, an island 11 to which a semiconductor chip is fixed is provided at the center of the frame 10, and a connecting body R is formed from each corner so as to surround the island 11 via suspension leads 12. In this connection body R, the first connection pieces 13 toward the island 11 are integrally disposed at substantially equal intervals. Further, a second connection piece 14 is provided outward from the coupling body R.

  This connection piece corresponds to a lead of a normal lead frame, and in the conventional lead frame, the lead is exposed from the resin sealing body. However, as shown in FIG. 3, the connection pieces 13 and 14 are cut at the surface of the resin sealing body 17 or protruded by about 0.1 to 0.2 mm. This protrusion is for making solder fillets on the side surfaces of the connection pieces 13 and 14 during mounting. The cutting method may be dicing, T / F (trim and forming), or the like.

  The number of connection pieces is determined by the number of bonding pad pads of the IC. In other words, if the number of pads is small, the first connecting piece 13 may be adopted. Further, the connecting piece arbitrarily selects one side to four sides of the connecting body, What is necessary is just to provide integrally. If the number is large, the second connection pieces 14 may be further employed. If the number of pads is larger, the third connection piece 22 may be provided in a ring shape on the outside as shown in FIG. Depending on the size of the connection piece, if another connection body is further formed on the outside of the connection body R via the suspension lead 12, and the connection piece facing the island and the connection piece facing the outside are provided, the connection piece The number of can be increased.

  That is, the connection piece has a shape in which a first connection piece group 13..., A second connection piece group 14.

  Subsequently, as shown in FIG. 2, the semiconductor chip 15 is fixed to the island 11 via a fixing material. Since the frame 10 is made of, for example, a metal mainly made of Cu, the fixing material is made of a brazing material such as solder, but may be a paste material such as a silver paste or an adhesive. Then, the bonding pads exposed on the surface of the semiconductor chip 15 are connected to the connection pieces 13 and 14 via the fine metal wires 16. The fine metal wire 16 is made of Au, Cu, Al, or the like, and is usually realized by wire bonding. As shown in FIG. 2, since the number of bonding pads of the IC is large, the first connection pieces 13 and the second connection pieces 14 are formed so as to protrude alternately around the side of the coupling body R. Yes. In other words, the second connection pieces 14 are inserted between the two adjacent first connection pieces 13 and 13, and are alternately projected to the left and right at a predetermined pitch around the coupling body R. By adopting this structure, short metal wires can be prevented from being short-circuited.

  Subsequently, as shown in FIG. 3, a resin sealing body 17 is provided. For example, the resin sealing body 17 can be realized by a transfer mold, an injection mold, or the like. However, the back surfaces of the connection pieces 13 and 14 are provided so as to be flush with the resin sealing body 17 or slightly protrude from the resin sealing body 17. At this time, when considering the insulation of the island, the island 11 may be pushed up slightly with respect to the connection piece and completely embedded as seen in the right diagram of FIG.

  Further, in FIG. 4, the first connection pieces 13 and the second connection pieces 14 are separated individually. FIG. 4 shows the back surface of the semiconductor device 18. Here, the first connection pieces 13, the second connection pieces 14, the suspension leads 12 and the island 11 are exposed. The area indicated by hatching is the removal area.

  Here, the connecting pieces 13 are separated from each other by removing the connecting body R. However, since the present frame has a frame unit formed in a matrix, the connection piece is cut at the side of the planned chip package.

  As a simple method of separation, here, dicing of the blade width indicated by hatching is performed in the direction indicated by hatching.

  In this dicing, if a groove slightly deeper than the thickness of the frame 10 is formed, it can be easily separated, and if even a small amount of the connecting body R remains, it causes a short circuit. Therefore, it is removed with a width wider than the width of the connecting body R. Yes. As another removal method, etching can be considered. The second connection piece 14 is cut to the end of the resin sealing body or at a position protruding 0.1 to 0.2 mm. The cutting method is performed by the same dicing as the conventional T / F or connecting body R is cut.

  In consideration of productivity, as shown in FIGS. 11, 14, and 15, a frame 10 on which semiconductor chips 15 can be mounted in a matrix form is prepared and diced together. This method will be described later.

  As described above, the present invention adopts the inexpensive frame 10 and finally removes the connecting body R by dicing or the like, so that an electrode composed of a connecting piece is formed on the side of the chip on the back surface of the resin sealing body 17. It will be. Compared with a package using a conventional lead frame, this connection piece has a shorter connection piece corresponding to the lead and can be reduced in overall size because it is not exposed to the outside.

  Moreover, since the size of a connection piece should just be a size which can wire bond a metal fine wire, the size can also be made small. The width of the connecting body R is determined by the size and accuracy of the dicing blade. However, since the recent dicing apparatus has a thin blade and very high accuracy, the width can be reduced. Therefore, a small semiconductor device can be easily realized.

  Further, the cut surfaces of the connecting pieces 13 and 14 are exposed in the grooves shown by hatching. If the soldering material such as solder is fixed to the mounting substrate as it is, the brazing material is wetted at the cut surface and a fillet is formed, so that the adhesive strength is also enhanced. In dicing, fine streaks are formed on the cut surface, so that biting with the brazing material is improved.

  On the other hand, the groove formed by dicing may be separately filled with resin. In particular, in a groove formed by dicing, the interface continuous with the semiconductor chip is a suspended lead. Therefore, in consideration of moisture resistance, the resin may be applied to the corner portion of the dicing groove. All the grooves may be filled. Also at this time, since the stripes by dicing are finely formed on the cut surface, the resin bite is good.

  When the groove is filled with an insulating resin, the brazing strength between the connection pieces 13 and 14 and the mounting board is enhanced by causing the back surface of the connection piece to protrude beyond the resin sealing body 17. A fillet is formed on the side surface exposed by the protrusion, and the adhesive strength of the brazing material is increased.

  5 and 6 show the frame 10 shown in FIG. 1 as a unit and the unit formed in a matrix.

  FIG. 5 shows a state after the package of FIG. 3, and a semiconductor chip is fixed to each island of the frame formed in a matrix shape, and a thin metal wire is connected thereto. The resin sealing body is provided over the entire area of the matrix frame. Here, the island is formed larger than the chip, but may be smaller.

  Then, dicing is performed at the locations indicated by the two types of arrows in FIG. 6, and separation of the connection pieces and separation from the frame as the semiconductor device are realized.

  As described with reference to FIG. 4, the portion of the coupling body in the entire frame is scraped off by dicing. This location is indicated by four small arrows in FIG. A full cut is then performed to separate the semiconductor device from the frame. This location is indicated by three large arrows.

  In the present method, a mold may be formed so that cavities are formed in a matrix like a normal transfer mold. However, in the present invention, as shown in FIG. 5, the mold is made into one cavity, and the frame units from end to end are all molded integrally and continuously, and then separated by dicing individually. Dicing uses two types of half-cut and full-cut, and separates connection pieces and semiconductor devices. When cavities are formed in a matrix in a mold, a space is required between the cavities on the mold side. However, if full cutting is performed by dicing, the area of the full cut area (large arrow) shown in FIG. 6 only needs to be a blade interval, so that the mounting density of the unit frame can be increased accordingly.

  Here, the island may be omitted and the X lead may be used.

  Further, reference numeral F in FIG. 4 is a fixing means that is located at or near the corner of the resin sealing body and is formed wider than the width of the suspension lead 12. Since this portion is completely separated by dicing, it is used here as a strain absorbing means.

  That is, the portions where the resin sealing body is distorted are the four corners of FIG. Therefore, a second fixing means corresponding to the portion F is provided on the mounting board, and the fixing means F and the second fixing means for the mounting board are fixed with a brazing material, silver paste, adhesive, or the like. As a result, even if a large strain that causes cracks in the solder balls or solder bumps is applied, the stress is first applied to the fixing means, and no stress is applied to the other connecting portions. Specifically, F is a lead, and the second fixing means of the mounting substrate is also formed with a pattern mainly made of Cu and soldered therebetween.

  Next, a second embodiment will be described with reference to FIGS. Here, the semiconductor chip 15 is mounted face-down on the frame to provide a semiconductor device having the same size as the chip size.

  The semiconductor chip 15 has solder bumps or solder balls formed on the surface thereof, which are indicated by black circles and connected to the connection pieces 13 and 14. In FIG. 2, an island is required for face-up and a suspension lead is also required. However, in FIG. 9, since it is realized by face-down, the island and the suspension lead indicated by a two-dotted line are omitted. good. The solder may be other brazing material. Also, a conductive paste such as silver paste may be used.

  Further, after the chip is mounted, the resin may be filled between the semiconductor chip and the frame.

  FIG. 10 shows the back surface of the previous figure, and the connecting body R in the portion indicated by the dotted line is also removed by dicing or the like, and the connection pieces 13 and 14 are individually separated. The island 11 and the suspension lead 12 are indicated by dotted lines because they can be omitted.

  The frame is formed in a matrix shape, and the second connection piece 14 is fully cut in the same manner as in FIG. The full cut may be dicing, T / F, or the like.

  This structure can be applied to a wafer size CSP as shown in FIG.

  That is, after a matrix-like IC is formed on the entire surface of the wafer 20, solder bumps and solder balls are formed via a passivation film. On top of this, a frame 21 configured in a matrix is arranged and connected to a connection piece.

  Then, if necessary, a resin is filled between the wafer and the frame, and the connecting body R is diced as shown in FIG. 6 to separate the connecting pieces individually, and the connecting body r provided between the frame units is fully cut. Separate them individually.

  Here, in both the first and second embodiments, various frames can be adopted. FIG. 11 shows a frame in which connection pieces 13 are provided on two opposite sides as shown in FIG. As shown in FIG. 13, first connection pieces 13, second connection pieces 14, and third connection pieces 22 may be provided so as to surround the island.

  On the other hand, a metal foil sandwiched on a flexible sheet may be used for the frame used in all the examples. In this case, it is sandwiched except for connection points (connection pieces, islands).

  16 and 17 are cross-sectional views of the first embodiment and the second embodiment. Since the connecting pieces 13 and 14 are small in size and may be peeled off during dicing, the resin biting means T is provided from the connecting pieces. 4, the biting means T is provided on any one of the three sides of the connection piece that does not coincide with the dicing line, and further protrudes from the side surface of the connection piece, and is completely covered with resin. Fixed by effect. Due to this anchor effect, the connecting piece is fixed without being peeled off from the resin even when the coupling body is cut by dicing.

  In FIG. 16, since a predetermined interval is provided between the semiconductor chip 15 and the frame, a part of the connection piece 13 can be disposed under the semiconductor chip 15. Thereby, the whole arrangement | positioning area | region of a connection piece can be shrunk, and the whole size can be made small.

It is a figure explaining the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention. It is a figure explaining the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention. It is a figure explaining the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention. It is a figure explaining the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention. FIG. 2 is a diagram when the unit frames of FIG. 1 are formed in a matrix. It is a figure explaining the isolation | separation method when isolate | separating FIG. 5 separately. It is a figure explaining the manufacturing method of the conventional semiconductor device. It is a figure explaining the manufacturing method of the conventional semiconductor device. It is a figure explaining the manufacturing method of the semiconductor device which concerns on 2nd Embodiment. It is a figure explaining the manufacturing method of the semiconductor device which concerns on 2nd Embodiment. It is a figure explaining a matrix-like frame. It is a figure explaining a frame. It is a figure explaining a frame. It is a figure explaining a frame. It is a figure explaining a frame. In the first embodiment, the connection piece is provided with biting means. In the first embodiment, the connection piece is provided with biting means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic substrate 2 Semiconductor chip 3 Pad electrode 4 Pad 5 Resin sealing body 10 Frame 11 Island 12 Suspension lead 13 1st connection piece 14 2nd connection piece 15 Semiconductor chip 16 Metal fine wire 17 Resin sealing body 20 Semiconductor wafer 21 Frame r Linkage R Linkage

Claims (7)

A semiconductor device mounted on a mounting board,
A semiconductor chip;
A resin sealing body for sealing the semiconductor chip;
A connection piece and a fixing means exposed on the back surface of the resin sealing body,
The back surface of the resin envelope is rectangular in plan view,
The connection piece is electrically connected to the semiconductor chip,
It said fixing means is a means which is fixed to a predetermined portion of the mounting substrate, wherein the semiconductor chip and electrically insulating, and is formed so as to separate Oite one another at the corners of the four positions of the back A semiconductor device.   The semiconductor device according to claim 1, wherein the connection piece and the fixing unit are made of the same material. A groove is formed on the back surface so as to surround the semiconductor chip,
2. The semiconductor device according to claim 1, wherein the connection means is formed to protrude alternately around the groove.   The semiconductor device according to claim 3, wherein a solder resist is embedded in the groove.   4. The semiconductor device according to claim 3, wherein the connecting means and the semiconductor chip are electrically connected by a thin metal wire. The semiconductor chip is fixed to the island,
The island is formed on the same plane as the connection piece and the fixing means,
The island and the groove are connected by a suspension lead,
The fixing means and the suspension lead are formed on the same straight line,
The semiconductor device according to claim 5, wherein the fixing unit is wider than the suspension lead.   4. The semiconductor device according to claim 3, wherein the semiconductor chip is mounted face-down and electrically connected to the connection means.