JP2002100691A - Container for housing semiconductor light-receiving element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of light-receiving element malfunctions due to a gap generated between a frame body and a ceramic substrate, dust remained in the gap, and the dust adhered to the light-receiving element, and to prevent adhesive from spreading out to the mounting surface of the semiconductor light-receiving element when the frame body and the ceramic substrate are bonded together. SOLUTION: Notched parts 5 are formed almost entirely around the inside circumference of the resin frame body 2 on the bonding side of the resin frame body 2, where the arithmetic average of the surface roughness Ra on the inner surface of the notched part 5 is 0.05 to 0.4 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container for housing a semiconductor light receiving element having a hollow portion for mounting and receiving a semiconductor light receiving element such as a long CCD for a line sensor used for a facsimile or an image scanner.

[0002]

2. Description of the Related Art Conventionally, a line sensor used for a facsimile or an image scanner of OA equipment includes a semiconductor light receiving element such as a long line sensor CCD (Charge Coupled Device). It is configured by being mounted on a container (hereinafter, referred to as a semiconductor container). In such a semiconductor container, a ceramic package having a mounting portion for a semiconductor light receiving element in a concave portion formed on the upper surface of a ceramic substrate has been used. Then, a semiconductor light receiving element is die-bonded to the mounting portion, and electrical wiring is performed by a bonding wire or the like.
The opening of the concave portion was used as a line sensor by sealing a transparent window made of glass or plastic.

Further, in order to meet various specifications and demands for cost reduction, potting with a light-transmitting sealing resin is performed instead of sealing a transparent window, or a plastic package using a resin substrate instead of a ceramic substrate. Was used.

[0004] Recently, a semiconductor light receiving element housing container having a high dimensional accuracy of a mounting surface and excellent heat dissipation by bonding an adhesive to a resin frame body holding a plurality of lead frames and a ceramic substrate. Has been proposed (see JP-A-12-138305).

Further, as another conventional example, a groove is provided along the inside of the seal portion of the container main body to prevent the sealing material for bonding the container main body and the cap from flowing into the central portion of the container main body. A semiconductor device having a configuration has been proposed (see Japanese Patent Application Laid-Open No. 3-266453).

[0006]

However, in the container for accommodating a semiconductor light receiving element disclosed in Japanese Patent Application Laid-Open No. 12-138305 as shown in FIG.
When bonding is performed with the thermosetting adhesive 14, the adhesive 14 shrinks during curing, and a gap A may be generated between the ceramic substrate 11 and the resin frame 12, and dust is easily caught in the gap A. Thus, it has been difficult to remove dust even in the cleaning process. As a result, a part of the dust may be scattered after the package is sealed, and the dust may adhere to the surface of the semiconductor light receiving element, causing the semiconductor light receiving element to malfunction.

In order to reduce material costs, the adhesive 1
When the width of 4 is reduced, the gap A between the ceramic substrate 11 and the resin frame 12 becomes larger than in the case of FIG. 6, whereby the dust is more likely to be trapped, and the dust trapped in the cleaning step is almost removed. I could not do it. As a result, dust may further adhere to the surface of the semiconductor light receiving element, and the semiconductor light receiving element may malfunction. Furthermore, since the width of the adhesive 14 is small, the bonding strength between the ceramic substrate 11 and the resin frame 12 has been reduced.

On the contrary, when the width of the adhesive 14 is increased, FIG.
As shown in (1), the adhesive 14 protrudes from the mounting surface 11a at the time of joining, flows into the semiconductor light receiving element, adheres to the side surface of the semiconductor light receiving element, and affects the operating characteristics of the semiconductor light receiving element itself. .

On the other hand, as described in Japanese Patent Application Laid-Open No. Hei 3-266453, when a groove is provided in the mounting portion, there is a problem that the mounting surface of the semiconductor light receiving element becomes large and the package becomes large and heavy.

[0010] Accordingly, the present invention has been completed in view of the above problems, and an object thereof is to form a gap between the resin frame and the ceramic substrate, and the dust remains in the gap in the cleaning step, and the dust is removed. An object of the present invention is to solve the problem that a part of the adhesive adheres to the semiconductor light receiving element to cause a malfunction, and to prevent the adhesive from protruding to the mounting surface of the semiconductor light receiving element at the time of joining the resin frame and the ceramic substrate.

[0011]

A semiconductor container according to the present invention comprises:
A region surrounded by the ceramic frame on the upper surface of the ceramic substrate, the ceramic substrate and a resin frame having substantially the same outer dimensions as the ceramic substrate and holding a plurality of lead frames are joined by an adhesive. In a semiconductor light receiving element storage container having a semiconductor light receiving element mounting surface,
A cutout portion is formed on the joining surface side of the resin frame body over substantially the entire inner circumference of the resin frame body, and the arithmetic average roughness Ra of the inner surface of the cutout portion is 0.05 to 0.4 μm. It is characterized by being.

According to the present invention, a notch is formed on the joining surface side of the resin frame over substantially the entire inner periphery of the resin frame, and the arithmetic average roughness of the inner surface of the notch is provided. When Ra is 0.05 to 0.4 μm, dust remaining in the gap between the resin frame and the ceramic substrate can be easily removed in the cleaning step, and the dust does not adhere to the semiconductor light receiving element. The semiconductor light receiving element can operate normally. Further, the protrusion of the adhesive onto the mounting surface of the semiconductor light receiving element at the time of joining the resin frame and the ceramic substrate can be greatly reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The semiconductor container of the present invention will be described in detail below. FIG. 1 is a sectional view showing an example of an embodiment of a semiconductor container of the present invention, and FIG. 2 is a perspective view thereof.

1 and 2, 1 is a ceramic substrate, 2 is a resin frame having substantially the same external dimensions as the ceramic substrate 1, 3 is a plurality of lead frames sandwiched between the resin frames 2, 4 is a ceramic frame. It is a thermosetting adhesive for joining the substrate 1 and the resin frame 2. In this semiconductor container, a resin frame 2 integrally formed with a lead frame 3 on a ceramic substrate 1 is joined by an adhesive 4.

The ceramic substrate 1 of the present invention is formed of a plate, and has a mounting surface 1a of the semiconductor light receiving element in a region surrounded by the resin frame 2 on the upper surface thereof.

The ceramic material of the ceramic substrate 1 includes an aluminum oxide (Al ₂ O ₃ ) sintered body, a mullite (3Al ₂ O ₃ .2SiO ₂ ) sintered body, and an aluminum nitride (AlN) based sintered body. Body, silicon nitride (Si ₃ N ₄ )
Various ceramic materials such as high-quality sintered body, silicon carbide (SiC) -based sintered body, and glass ceramics can be used, and may be appropriately selected according to required characteristics such as dimensional accuracy, strength, and heat dissipation. Among them, when an aluminum oxide sintered body is used, it has a suitable thermal conductivity and is easily processed by polishing or the like, so that it has a mounting surface 1a with desired dimensional accuracy, strength, reliability, and heat dissipation. A semiconductor container having excellent characteristics and excellent characteristics can be obtained.

The resin frame 2 is bonded to the upper surface of the ceramic substrate 1 with an adhesive to form a space for accommodating the semiconductor light receiving element in a region surrounding the inner mounting surface 1a, and forms a container together with the ceramic substrate 1.

The resin material of the resin frame 2 includes epoxy resins such as bisphenol A type epoxy resin, novolak type epoxy resin, glycidylamine type epoxy resin, polyimide resin, phenol resin, unsaturated polyester resin, and silicone resin. Or other thermosetting resin, or
Thermoplastic resins such as liquid crystal polymer, polyphenylene sulfide resin, and polysulfone resin are used. Particularly, an epoxy resin is preferable from the viewpoint of good heat resistance and moisture resistance and low cost. Further, these resins may contain a curing agent, a curing accelerator, a filler, a flame retardant, a pigment, a release agent, and the like.

In order to manufacture the resin frame 2, for example, an injection molding method or a transfer molding method is used to put a plurality of lead frames 3 in a mold set at a predetermined position for about 5 to 5 minutes.
20MPa (megapascal) pressure, about 150-200
It may be manufactured by injecting and solidifying a resin material under molding conditions such as a temperature of ° C. and a molding time of about 1 to 10 minutes.

The metal mold for manufacturing the resin frame 2 is subjected to electric discharge machining after roughing the surface by cutting, and as shown in FIG. 3, the metal corresponding to the portion of the surface 6 where the notch 5 is provided. Only the mold is finished with an abrasive such as a whetstone, abrasive cloth, or loose abrasive. The notch 5 is formed in the ceramic substrate 1
Is formed on the inner side (on the mounting surface 1a side) of the surface to be joined. As shown in FIG. 1, the size of the notch 5 is preferably 0.1X to 0.5X with respect to the width X of the resin frame 2, and the thickness Y of the resin frame 2 on the lower side of the lead frame. 0.1 for
Y to 0.5Y is preferable. If it is less than 0.1X, dust remains in the gap between the ceramic substrate 1 and the resin frame 2, making it difficult to remove the dust in the cleaning process.
The adhesive strength between the ceramic substrate 1 and the resin frame 2 decreases,
The detachment of the resin frame 2 increases. If it is less than 0.1Y, dust remains in the gap between the ceramic substrate 1 and the resin frame 2, making it difficult to remove dust in the cleaning process. The thickness is reduced, the rigidity is reduced, and wire bonding defects increase.
Specifically, the length of X is about 2 to 8 mm, and the thickness of Y is about 0.25 to 1 mm.

Further, in order to prevent the mold from being worn by the flow of the resin at the time of molding, the surface of the mold is subjected to a surface hardening treatment.
Examples of the surface hardening method include hard chromium (Cr) plating, nickel (Ni) plating, Ni-Teflon coating, nitriding treatment, sulfurizing treatment, boride treatment, physical vapor deposition method (PDV method) such as TiN film, and TiN. It can be performed by a chemical vapor deposition method (CVD method) of a film or the like.

When resin molding is performed using this mold, the surface roughness of the mold is transferred to the surface of the semiconductor light receiving element housing container, and the surface is finished to have almost the same surface properties as the mold. And the notch 5
Has an arithmetic average roughness Ra of about 0.05 to 0.4 μm. If it is less than 0.05 μm, it is the processing limit of the molding die, and if it exceeds 0.4 μm, it becomes difficult to remove dust in the cleaning step. Preferably, 0.05-0.25μ
m is preferred.

Further, since the arithmetic average roughness Ra of the inner surface of the cutout portion 5 is 0.05 to 0.4 μm, generally large amount of dust having a size exceeding 0.4 μm hardly adheres. . Even if dust having a size of 0.05 μm or less adheres to the inner surface of the notch 5, such small dust often adheres to the inner surface by an intermolecular force with the inner surface. It is weak and can be easily removed in the washing process. Therefore, almost no dust adheres to the notch 5, so that the semiconductor light receiving element can be normally operated.

The arithmetic average roughness Ra of the ceramic substrate 1 is
0.15-1 μm is preferred. When the thickness is less than 0.15 μm, the adhesive strength with the adhesive 4 or the die bonding agent decreases, and the detachment of the ceramic substrate 1 increases. The optical system cannot be mounted with the required precision.

The lead frame 3 is made of an iron (Fe) -nickel (Ni) -cobalt (Co) alloy, an Fe-Ni alloy,
It is made of a metal material such as a copper (Cu) alloy, and is connected to a semiconductor light receiving element housed in a container by an electric connection means such as a bonding wire and is connected to an external electric circuit via solder or the like. , Function as a conductive path between them.

The lead frame 3 is made of, for example, Fe
-An ingot (a lump) of a Ni-Co alloy is formed into a predetermined shape and dimensions by applying a conventionally known metal working method such as a rolling method or a punching method. On the exposed surface, a highly conductive metal plating film such as nickel or gold having excellent corrosion resistance and good wettability with a brazing material or a bonding wire is applied to a thickness of 0.1 to 20 μm. By doing so, the oxidative corrosion of the lead frame 3 can be effectively prevented, and the electrical connection using a bonding wire, solder, or the like can be improved.

The adhesive 4 for joining the resin frame 2 to the upper surface of the ceramic substrate 1 is made of an epoxy resin containing acrylic rubber or the like. Specific examples of the adhesive composed of such an epoxy resin include an epoxy resin such as a bisphenol A type epoxy resin, a novolak type epoxy resin, a glycidylamine type epoxy resin, an amine type curing agent, an imidazole type curing agent, and an acid anhydride. Using a resin adhesive to which a curing agent such as a product curing agent has been added, and containing particles of acrylic rubber such as butyl acrylate rubber, cross-linked polymethyl methacrylate rubber, ethyl acrylate rubber, urethane acrylate rubber, etc. Used.

In order to join the ceramic substrate 1 and the resin frame 2 with such an adhesive 4, for example, a screen printing method or the like is first applied to a portion of the upper surface of the ceramic substrate 1 to be joined to the resin frame 2. The adhesive 4 is printed and applied in a frame shape by a dispenser method or the like. Next, the resin frame 2 is placed, and a heat treatment is performed at a temperature of 120 to 180 ° C. for about 5 minutes to 3 hours while applying a pressure of about 2 to 8 N (Newton) according to the curing characteristics of the adhesive 4. Then, the resin frame 2 is joined to the ceramic substrate 1 by thermally curing the adhesive 4.

The semiconductor light receiving element is mounted on the mounting portion of the semiconductor container of the present invention, and the electrodes of the semiconductor light receiving element and the lead frame 3 are electrically connected by a bonding wire or the like. By sealing a transparent window made of a resin or the like, or sealing a semiconductor light receiving element by potting with a light-transmitting sealing resin, a semiconductor light receiving device such as a line sensor used for a facsimile, an image scanner, or the like is obtained.

Thus, according to the present invention, a notch is formed on the joining surface side of the resin frame over substantially the entire inner periphery of the resin frame, and the inner surface of the notch has a smooth surface having a predetermined roughness. Accordingly, dust can be easily removed in the cleaning step, and the semiconductor light receiving element can be operated normally. Further, it is possible to greatly reduce the protrusion of the adhesive onto the mounting surface of the semiconductor light receiving element when the resin frame and the ceramic substrate are joined.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications and improvements can be made without departing from the gist of the present invention.
For example, the present invention can be applied to a semiconductor container having a hollow portion for mounting a semiconductor light receiving element such as a CCD for an area sensor used in a digital camera, a video camera, and the like. Also, the shape of the notch is different from that shown in FIG.
The shape of the notch may be an arc shape, a step shape, or the like in which the notch depth increases toward the inside. By adopting such a shape, the adhesion of dust can be more effectively prevented, and the ceramic substrate 1 It also has an effect that stress generated at the time of joining the resin frame 2 with the resin frame 2 can be reduced. Further, the inner surface 7 of the resin frame 2 other than the notch portion 5 also has an arithmetic average roughness Ra of 0.05 to 0.05.
By setting the thickness to 0.4 μm, there is an effect that dust adhesion can be further prevented and defects during wire bonding can be eliminated.

[0032]

According to the present invention, a cutout is formed on the mounting surface side of the resin frame over substantially the entire inner periphery of the resin frame, and the arithmetic mean roughness Ra of the inner surface of the cutout is zero. .0
Since the thickness is 5 to 0.4 μm, it is easy to remove dust remaining on the inner surface of the notch in the cleaning step, and dust does not adhere to the semiconductor light receiving element, and the semiconductor light receiving element can be operated normally. . Further, the protrusion of the adhesive onto the mounting surface of the semiconductor light receiving element at the time of joining the resin frame and the ceramic substrate can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an embodiment of a semiconductor container of the present invention.

FIG. 2 is a perspective view showing an example of an embodiment of a semiconductor container of the present invention.

FIG. 3 is an enlarged sectional view of a main part of the semiconductor container of FIG. 1;

FIG. 4 is an enlarged sectional view of a main part showing an example of another embodiment of the semiconductor container of FIG. 1;

FIG. 5 is a sectional view of a conventional semiconductor container.

FIG. 6 is an enlarged sectional view of a main part of a conventional semiconductor container.

FIG. 7 is an enlarged sectional view of a main part of a conventional semiconductor container.

[Explanation of symbols]

 1: Ceramic substrate 2: Resin frame 3: Lead frame 4: Adhesive 5: Notch

Claims (1)

[Claims] 1. A resin frame on an upper surface of a ceramic substrate, comprising: a ceramic substrate; and a resin frame having substantially the same outer dimensions as the ceramic substrate and holding a plurality of lead frames. A semiconductor light-receiving element storage container having a mounting surface of the semiconductor light-receiving element in a region surrounded by a notch formed on the joining surface side of the resin frame over substantially the entire circumference inside the resin frame. And the arithmetic average roughness Ra of the inner surface of the notch is 0.05 to
A semiconductor light receiving element storage container having a thickness of 0.4 μm.