JP2008103415A - Hollow semiconductor package made of resin and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow semiconductor package made of resin, where the hollow semiconductor package has dimension precision ideal for mounting a semiconductor element having an optical function of for example a solid-state image pickup device and a high degree of freedom in wiring inside the package, at low costs without deteriorating reliability, such as moisture resistance. <P>SOLUTION: An electric conductive circuit 3 is drawn on an insulating tape 1 fixing an inner lead terminal, a through hole 2 passing through the circuit and a corresponding inner lead terminal is filled with a conductive substance, and the circuit drawn on the insulating tape is connected to the corresponding inner lead terminal electrically, thus enabling the crossed wiring of the lead terminal in the hollow semiconductor package made of resin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resin hollow semiconductor package on which a semiconductor element such as a solid-state imaging element is mounted, and particularly to a resin hollow semiconductor package that requires complicated circuit wiring inside, and is used for a small and thin digital camera, It relates to the manufacturing method.

The characteristics of a semiconductor element are degraded due to changes in ambient humidity and temperature, contact with fine dust and foreign matter, and the like, and the semiconductor element is easily damaged when subjected to vibration or impact. In order to protect the semiconductor element from these external factors, it is usually used as a semiconductor package by sealing with a ceramic box or resin.
In the case of a solid-state imaging device such as a CCD or C-MOS, or a semiconductor device having an optical function such as a laser diode or a photodiode, a light path is required between the semiconductor device and the outside of the semiconductor package on which the semiconductor device is mounted. Therefore, the periphery of the semiconductor element cannot be completely sealed with resin or ceramics.
Therefore, in the case of a semiconductor element having these optical functions, the semiconductor package is generally mounted in a hollow type package in which one side is opened, and the open part is sealed using an optically transparent window material such as glass. It is used as.

In recent years, a huge market for digital cameras has been formed. While higher functions such as higher image quality and higher zoom ratio are required, there is a high demand for downsizing and weight reduction. In particular, there is a strong demand for a camera specialized in thinning called a card type.
Compared to a single focus lens, a zoom lens has a longer lens barrel, and it is difficult to reduce the thickness of the camera body while mounting the zoom lens. Therefore, by using a prism to bend the optical axis of the lens system by 90 ° and storing it in the body, a digital camera having a thin body while mounting a lens with a high zoom ratio has come to the market.
In this system, the optical axis of the solid-state image sensor used is parallel to the surface of the camera body. Therefore, when thinning the camera, the solid-state imaging device or the hollow semiconductor package mounting the solid-state imaging device is not thinned in the thickness direction of the solid-state imaging device or the hollow semiconductor package mounting the solid-state imaging device. Therefore, it is required to reduce the thickness in the direction perpendicular to the surface of the camera body, that is, in the width direction of the solid-state imaging device or the hollow semiconductor package on which the solid-state imaging device is mounted.

A solid-state imaging device usually has connection terminals on each of four sides of a rectangular shape, but one pair of lead terminals in a hollow semiconductor package is bent by 90 ° to make a relative If it is possible to dispose only one set of sides to extend to the outside, the hollow semiconductor package can be thinned in the direction of one set of opposite sides of the hollow semiconductor package in which the lead terminals do not extend. Has the advantage of being able to
However, in a resin-made hollow semiconductor package in which a lead frame used in the past is inserted into a molding die and molded resin is injected and insert molding is performed, in order to perform the above arrangement, if the lead terminal bent 90 ° is long Inevitably, the inner lead sinks in the insert molding process, and the tip of the inner lead is covered with a resin burr, which makes it impossible to perform wire bonding with the semiconductor element to be mounted.

  As a solid-state imaging device used for a digital camera, it was once evaluated that a C-MOS is cheaper than a high-quality but high-quality CCD, but the image quality as high as that of a CCD cannot be obtained. Recently, however, C-MOS technology has also advanced, and C-MOS type image sensors have come to be used in high-end models such as digital single-lens reflex cameras. In principle, the C-MOS type image pickup device has a feature that the number of connection terminals is remarkably larger than that of the CCD, and the arrangement order of the terminals may not correspond to the function depending on the device. For this reason, there has been a demand for a cross-wiring between the lead terminals in the package for the resin-made hollow semiconductor package on which the C-MOS type imaging device is mounted.

As a hollow semiconductor package on which a solid-state imaging device is mounted, there is a ceramic hollow semiconductor package in addition to a resin one. For a hollow semiconductor package on which a solid-state image sensor is mounted, a resin-made hollow semiconductor package having excellent dimensional accuracy is preferably used because it is necessary to adjust the optical axis or focus of the optical system.
On the other hand, in the resin-made hollow semiconductor package, the lead terminals cannot be cross-wired in the package. Therefore, when the cross-wiring is necessary, a ceramic hollow package having a high degree of freedom of wiring has been used. In particular, a ceramic hollow semiconductor package of a type called CLCC (ceramic leadless chip carrier), which can be easily cross-wired by drawing a wire by a plating method, has been suitably used.
However, since CLCC is produced by laminating and sintering a plurality of ceramic sheets called green sheets, there is a problem that warpage and tilt due to sintering are large and dimensional accuracy is inferior.

There is also a hollow semiconductor package in which a printed wiring board is used as a base and a resin frame is bonded or integrally molded thereto. However, with this method, the thickness of the printed wiring board varies greatly, and mounting a semiconductor with an optical function such as an image sensor does not meet the dimensional accuracy in the height direction, so careful height adjustment is required during mounting. It becomes cost rise. The mounting method on the external substrate is a BGA type mounting method in which solder balls are arranged on the back side of the printed wiring board. This mounting method is also a factor that deteriorates the height accuracy of the hollow semiconductor package with respect to the external substrate. .
Furthermore, the printed wiring board has a high hygroscopicity, and there is a problem that the moisture resistance as a package is lowered and sufficient reliability cannot be obtained.

For a solid package or a full mold package (hereinafter referred to as a solid package) that does not have a hollow portion for mounting a semiconductor element, the leads are fixed in Japanese Patent Laid-Open No. 6-85149 (Patent Document 1). The structure is provided with a plurality of bondable conductors scattered on the surface of the insulating fixing tape, and a part of the surface of the insulating fixing tape is used when connecting the external terminals of the semiconductor element and the lead frame. An invention is disclosed in which wire bonding is performed via conductor parts that can be bonded and scattered. The present invention is effective in a solid package that can secure a sufficient space for wire bonding. However, in the case of a hollow semiconductor package, the wire bonding in the package needs to be wired in a narrow resin side wall portion, so that it is easily implemented. Can not. Specifically, when the resin is injected in the insert molding process, there is a problem that the bonding wires are short-circuited or the bonding wires are disconnected more easily than the solid package.
In the case of a solid package, the semiconductor element to be mounted and the lead frame are first wire-bonded, and then the wire-bonded semiconductor element is placed in a molding die and insert molding is performed. Wire bonding the conductor portion and the semiconductor element or the lead frame scattered on the surface of the insulating fixing tape for fixing the lead does not increase a new process and does not significantly increase the manufacturing cost.
However, in the case of a hollow semiconductor package, a semiconductor element is mounted on the completed package and wire bonding is performed later. Therefore, when the method of Patent Document 1 is applied to the hollow semiconductor package, it is newly added before insert molding of the package. It becomes necessary to add a wire bonding process. For this reason, there exists a problem which raises the manufacturing cost of a hollow semiconductor package to such an extent that it cannot be disregarded.

Therefore, in order to increase the degree of freedom of wiring in the package of the hollow semiconductor package, Japanese Patent Laid-Open No. 2006-128354 (Patent Document 2) embeds a conductor in a groove having a wiring pattern stamped on a resin package, An invention in which a wiring pattern in which a body is embedded and a lead frame are used together is disclosed.
However, there is a need for a resin hollow semiconductor package with a high degree of freedom of wiring in the package that can be manufactured at a lower cost by a more rational process.
JP-A-6-85149 JP 2006-128354 A

  The present invention provides a resin-made hollow semiconductor package having a dimensional accuracy suitable for mounting a semiconductor element having an optical function such as an image pickup element and having a high degree of freedom of wiring inside the package to the extent that cross wiring is possible. It is an object to provide at low cost without impairing reliability such as moisture resistance.

A resin-made hollow semiconductor package having a hollow portion for mounting a semiconductor element, which is insert-molded by inserting a lead frame into a molding die and injecting molding resin, and having an insulating property for fixing an inner lead terminal An inner lead terminal corresponding to the circuit drawn on the insulating tape by drawing an electrically conductive circuit on the tape and filling a through hole penetrating the inner lead terminal corresponding to the circuit with a conductive substance A resin hollow semiconductor package that enables cross wiring of lead terminals by electrically connecting the terminals is used.
In the present invention, the resin-made hollow semiconductor package that enables the cross wiring of the lead terminals is a semiconductor element mounted on the resin-made hollow semiconductor package by changing the relative arrangement of the terminals inside the resin-made hollow semiconductor package. This means that the arrangement of external connection terminals and the arrangement of terminals extending to the outside of the resin hollow semiconductor package do not completely match. For example, a part of the array of external connection terminals of the rectangular semiconductor element is reversed in the array of external terminals extending to the outside of the resin hollow semiconductor package. In addition, the resin hollow semiconductor package capable of cross-wiring of the present invention includes a semiconductor hollow semiconductor package having external connection terminals extending from only two sides while mounting a semiconductor element having external connection terminals on four sides. It is.
It is one of the preferable embodiments of the present invention that the electrically conductive circuit drawn on the insulating tape is printed with conductive ink or conductive paste. Moreover, it is one of the other preferable aspects of this invention to use the flexible printed circuit board which laminated | stacked the polyimide film and copper foil as an insulating tape with which the electroconductive circuit was drawn.
In addition, an insulating tape is provided in a lower package of the hollow portion on which the semiconductor element is mounted, and the conductive tape is electrically conductive on the insulating tape in the package in a range of 50% to 150% of the bottom area of the hollow portion. A resin-made hollow semiconductor package printed with ink or conductive paste is a preferred embodiment in improving moisture resistance and providing a highly reliable resin-made hollow semiconductor package. Alternatively, providing a metal thin plate instead of printing the conductive ink or conductive paste is also effective in improving the moisture resistance of the resin hollow semiconductor package.

Furthermore, as a method for providing the resin-made hollow semiconductor package of the present invention, a step of applying an insulating tape to the lead frame, a step of drawing an electrically conductive circuit on the insulating tape attached to the lead frame, the lead frame It is a preferable aspect that the step of placing the substrate in the mold and injecting molding resin to insert molding is arranged in this order to manufacture the resin hollow semiconductor package.
Also, a step of drawing an electrically conductive circuit on an insulating tape, a step of attaching an insulating tape on which an electrically conductive circuit is drawn to a lead frame, and placing the lead frame on a mold and molding resin It is a preferable aspect to arrange the steps of injecting and insert molding the resin hollow semiconductor package in this order.
Alternatively, a step of preparing a flexible printed circuit board having a desired circuit pattern, attaching the flexible printed circuit board to a lead frame, placing the lead frame on a mold, injecting a molding resin, and performing an insert molding process, It is a preferable aspect to arrange the resin-made hollow semiconductor packages in order.

Each component of the resin hollow semiconductor package of the present invention will be described below.
(Lead frame) In the lead frame used in the present invention, in a completed resin hollow semiconductor package, an insulating tape on which an electrically conductive circuit is drawn is fixed to a lead in a portion buried in the resin package. It is a feature.
The lead frame used in the present invention can be suitably used as long as it is a lead frame used for ordinary semiconductor encapsulation, and a lead frame made of 42 alloy or copper alloy is preferably used. 0.1 to 0.25 mm has a good balance between workability and strength, and can be preferably used in terms of cost.

(Insulating Tape) The insulating tape used in the present invention is preferably a tape that does not generate ionic impurities in order to prevent an electrical defect from occurring in a semiconductor element to be mounted. Specifically, films such as polyimide, epoxy, polyethersulfone, polyetherketone, and liquid crystal polymer that are used for mounting semiconductor elements can be suitably used.
In the present invention, such an insulating tape is used by being affixed to a lead frame. As a method for affixing the insulating tape to a lead frame, it may be fixed using an adhesive, An adhesion method using sonic bonding, ACF (anisotropic conductive film), ACP (anisotropic conductive paste) or the like can be suitably used.
The position where the insulating tape is affixed to the lead frame may be affixed to any position on the lead frame as long as the object of the present invention can be achieved, but the inner lead part or the inner lead part and the outer lead It is preferable to affix to the lead intermediate part which communicates with the part.
When affixing insulating tape to the inner lead, it can be expected to suppress the sinking or fluttering of the inner lead tip during insert molding by applying it to the back side of the lead frame. The production yield can be improved by suppressing the occurrence of burrs.
When affixing an insulating tape to the lead intermediate portion, the insulating tape may be affixed to one or both sides of the front side or the back side of the lead frame. The electrical conductive circuit pattern drawn on the insulating tape affixed to the front side and the electrical conductive circuit pattern drawn on the insulating tape affixed to the back side can be modified appropriately to create complex Wiring can be made possible. Furthermore, it is also possible to carry out wiring within a more complicated package by applying an insulating tape on which a desired electrical conductive circuit pattern is drawn to both the lead intermediate part and the inner lead tip part. It belongs to the range.
It is natural that the electrically conductive circuit drawn on the insulating tape is drawn on the surface of the insulating tape that is not in contact with the lead frame so as not to short-circuit the lead frame.
As the electrically conductive substance for drawing an electrically conductive circuit on the insulating tape, a conventionally known material can be appropriately used. Conductive inks and conductive pastes such as silver paste and copper paste can be suitably used.

(Through Hole) In the present invention, the lead frame and the insulating tape on which an electrically conductive circuit is drawn are electrically connected by filling the through hole that communicates the two with a conductive substance. A hole was previously provided in the insulating tape on which the electrically conductive circuit was drawn using a laser or a drill, and the electrically conductive circuit was drawn on the lead frame so that the through hole corresponded to the target lead. Insulating tape may be affixed, or insulative tape with an electrically conductive circuit without holes drawn on a lead frame without holes, followed by drilling through holes with a laser or drill. Also good.
By filling the through hole with an electrically conductive substance, electrical conduction between the lead frame and the insulating tape on which the electrically conductive circuit is drawn is ensured. As a result, an electric signal from the inner lead can be output to the outer lead at a desired position.

(Insert molding) In the present invention, an electrically conductive substance is placed in a through-hole that communicates an electrically conductive circuit and the lead frame with respect to the lead frame to which an insulating tape depicting an electrically conductive circuit is attached. Fill and make electrical connection between the electrically conductive circuit on the insulating tape and the lead frame. A lead frame attached with an insulating tape on which an electrically conductive circuit that has been electrically connected is attached is placed in a molding die, a molding resin is injected, and insert molding is performed. An integrated resin hollow semiconductor package is molded.
Various known molding methods can be used as the molding method for insert molding, but transfer molding is preferable because the amount of molding resin to be injected can be precisely controlled.
As the molding resin used for molding, a known resin can be used as appropriate, but an epoxy resin to which a filler such as silica is added is generally considered in consideration of dimensional stability, workability, moisture resistance, cost, etc. Used for.

  EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 FIG. 1 shows a top view of an insulating tape used in Example 1. FIG. As the insulating tape, a polyimide film having a thickness of 25 μm is used, and through holes are drilled at 40 positions shown in FIG. Since the surface of this insulating tape is provided with an adhesive layer made of thermoplastic polyimide, it can be attached to the lead frame by thermocompression bonding.
FIG. 2 is a bottom view of the insulating tape, and shows a circuit pattern drawn using electrically conductive ink.
FIG. 3 is a top view of the lead frame used in the first embodiment. In Example 1, a lead frame made of 42 alloy having a thickness of 0.25 mm is used.
The state in which the insulating tape on which the electrically conductive circuit pattern shown in FIG. 1 and FIG. 2 is drawn is attached to a desired position on the back surface of the lead frame shown in FIG. 3 using ACF (anisotropic conductive film). As shown in FIG. The desired position is a position where the through hole on the insulating tape shown in FIG. 1 overlaps each corresponding inner lead of the lead frame shown in FIG.

The lead frame thus prepared was inserted into a molding die, and a resin hollow package was integrally molded by transfer molding using an epoxy compound as a molding resin. FIG. 6 shows a top view of the resin hollow package of the present invention formed by cutting the dam bar between the outer leads and further cutting the outer leads after taking out from the molding die.
With the circuit pattern shown in FIG. 2, the inner lead terminals located in the left half of the upper side of FIG. 6 are connected except for one of the left ends and the upper end of the outer lead terminal located in the upper half of the left side. Become. Similarly, the inner lead terminals located in the right half of the upper side are the inner lead terminals located in the left half of the lower side except for one of the right ends, and the upper end of the outer lead terminal located in the upper half of the right side. Except for the one at the left end, except for the lower end of the outer lead terminal located in the lower half of the left side, respectively, and the inner lead terminal located in the right half of the lower side, respectively, in the lower half of the right side except for the right end It is connected to each except the lower end of the located outer lead terminal.

According to the present invention, the inner lead terminal can be electrically connected to an arbitrary outer lead that is not in direct communication with the inner lead, and the degree of freedom of wiring in the resin hollow package is remarkably improved.
Here, the inner 10 pins excluding both ends of the inner lead terminals located on the upper side and the lower side exposed in the hollow portion of the resin hollow package are changed to the inner 10 pins excluding both ends of the outer lead extending from the left side and the right side. In the case of electrical connection, the specific terminals of the inner leads located on the four sides of the hollow portion can be electrically connected to any outer leads extending from the outer side of the package. Not too long.
In addition, multiple insulating tapes with different circuit patterns drawn on the back surface of the lead frame are pasted on top of each other, and the different circuit patterns drawn on the multiple insulating tapes do not overlap. By drilling through-holes at the positions where it is necessary, it is possible to easily implement the complicated circuit arrangement.

(Example 2)
FIG. 7 shows a top view of the insulating tape used in Example 2. FIG. The insulating tape shown in FIG. 7 is also a polyimide film having a thickness of 25 μm, but unlike the first embodiment, the conductive tape pattern is not drawn on the insulating tape shown in FIG. It is only perforated. In the same manner as in Example 1, this was bonded to the lead frame by thermocompression bonding so as to be in a desired position. FIG. 8 is a top view showing a state in which the insulating tape shown in FIG. 7 is bonded to the lead frame. Thereafter, a desired circuit pattern is drawn on the back surface of the insulating tape adhered to the lead frame using a conductive ink or conductive paste. As a drawing means, scanning may be performed using a dispenser so that a circuit pattern is formed, or screen printing may be used. Further, it is possible to suitably perform drawing by applying an ink jet printer.

At this time, a conductive hole or a conductive paste is also filled in a through hole that has been drilled in advance to establish electrical continuity with the lead frame. Therefore, the through hole is previously drilled at a position corresponding to the circuit pattern to be drawn.
An embodiment of the present invention includes using an insulating tape in which through holes are not drilled, bonding to a lead frame, drilling with a drill or a laser, and then drawing a conductive circuit pattern.
The lead frame thus prepared can be inserted into a molding die, and a molding resin can be transfer molded to mold a resin hollow package substantially equivalent to the first embodiment.

  FIG. 9 shows an insulating tape used in an embodiment according to claim 4 of the present invention. Unlike the insulating tape used in Examples 1 and 2, the finished resin hollow package also has an insulating tape in the center of the resin hollow package so as to cover the hollow portion where the semiconductor element is mounted. is doing. After this insulating tape is bonded to the lead frame, a rectangular drawing portion is provided at the center so as to cover the semiconductor element mounting portion together with the conductive circuit pattern on the back surface of the insulating tape. This is shown in FIG. As a result, the rectangular portion drawn at the center of the insulating tape in the completed resin hollow package prevents the infiltration of moisture entering from the back surface of the resin hollow package and greatly improves the moisture resistance of the resin hollow package. It becomes possible.

  According to the present invention, a resin hollow package having a dimensional accuracy suitable for mounting a semiconductor element having an optical function such as an image pickup element and having a high degree of freedom of wiring inside the package to the extent that cross wiring is possible. While providing high moisture resistance, it can be provided at low cost, and a thin and high-quality digital camera can be produced at low cost.

It is the top view seen from the upper surface side of the insulating tape used in Example 1. FIG. It is the top view seen from the lower surface side of the insulating tape used in Example 1. FIG. FIG. 3 is a plan view of the lead frame used in Example 1 as viewed from the upper surface side. FIG. 3 is a plan view of the state in which an insulating tape is applied to the lead frame of Example 1 as viewed from the upper surface side. FIG. 2 is a plan view of a state in which an insulating tape is attached to the lead frame of Example 1 as viewed from the lower surface side and a partially enlarged view thereof. It is the top view which looked at the resin-made hollow semiconductor packages created in Example 1 from the upper surface side. It is the top view seen from the upper surface side of the insulating tape used in Example 2. FIG. It is the top view which looked at the state which stuck the insulating tape on the lead frame of Example 2 from the upper surface side. It is the top view seen from the upper surface side of the insulating tape of another aspect. It is the top view seen from the lower surface side of the insulating tape which drawn the rectangular part in the center part of the other aspect.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating tape 2 Through hole 3 Circuit pattern 41 Lead frame 42 Inner lead 43 Outer lead 5 Resin hollow package

Claims (7)

A resin-made hollow semiconductor package having a hollow portion for mounting a semiconductor element, in which a lead frame having an inner lead terminal fixed with an insulating tape is inserted into a molding die and molded resin is injected to be insert-molded. Then, draw an electrically conductive circuit on the insulating tape that fixes the inner lead terminal, and fill the through hole that penetrates the circuit and the corresponding inner lead terminal with a conductive substance to make the insulating tape. A resin-made hollow semiconductor package characterized in that cross wiring of lead terminals is made possible by electrically connecting drawn circuits and corresponding inner lead terminals. The resin hollow semiconductor package according to claim 1, wherein the electrically conductive circuit drawn on the insulating tape is printed with a conductive ink or a conductive paste. Plastic hollow semiconductor package. 2. The resin hollow semiconductor package according to claim 1, wherein the insulating tape on which an electrically conductive circuit is drawn is a flexible printed board. 4. The resin hollow semiconductor package according to claim 1, wherein an insulating tape is provided in a lower package of the hollow portion on which the semiconductor element is mounted, and the hollow portion is provided on the insulating tape in the package. A resin-made hollow semiconductor package, wherein a metal thin film is present in a range of 50% to 150% of the bottom area, or a conductive ink or conductive paste is printed. A process of applying an insulating tape to the lead frame, a process of drawing an electrically conductive circuit on the insulating tape applied to the lead frame, an insert molding by placing the lead frame on a mold and injecting a molding resin A process for producing a resinous hollow semiconductor package comprising arranging the steps to be performed in this order to produce a resinous hollow semiconductor package. Drawing an electrically conductive circuit on an insulating tape, attaching an insulating tape on which an electrically conductive circuit is drawn to a lead frame, placing the lead frame on a mold and injecting a molding resin Then, a resin hollow semiconductor package is manufactured by arranging the steps of insert molding in this order to manufacture a resin hollow semiconductor package. A flexible printed circuit board having a desired circuit pattern is prepared, the process of attaching the flexible printed circuit board to a lead frame, the process of placing the lead frame on a mold, injecting molding resin and insert molding, are arranged in this order. And manufacturing a resin hollow semiconductor package. A method for manufacturing a resin hollow semiconductor package.