JP5161672B2 - Package for receiving semiconductor light receiving elements - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic semiconductor light receiving element storage package provided with a metal external connection terminal fixed to be electrically connected to the outside, and more specifically, a CCD (Charge Coupled Device) type. Further, the present invention relates to a package for housing a semiconductor light receiving element, which is mounted with a semiconductor light receiving element such as a MOS (Metal Oxide Semiconductor) type and is electrically connected to the outside via an external connection terminal.

  2. Description of the Related Art Conventionally, semiconductor light receiving elements are easily damaged by moisture, chemical substances, etc. in the atmosphere when directly sensing light, and handling thereof requires attention. The semiconductor light-receiving element storage package for storing the semiconductor light-receiving element includes, for example, a flat plate-shaped ceramic base, a window frame-shaped ceramic frame, and an Fe—Ni-based alloy (hereinafter referred to as a “frame”). The external connection terminal made of 42 alloy is joined with glass. Further, the semiconductor light receiving element storage package has a thickness of about 1.0 to 8.0 μm in order to prevent external oxidation on the surface of the external connection terminal exposed to the outside or to secure wire bonding property. The Ni plating film and an Au plating film of about 0.1 to 0.3 μm are applied on this upper surface. In this semiconductor light receiving element storage package, a semiconductor light receiving element is mounted in a cavity formed by a ceramic base and a ceramic frame, and bonding pads provided on the semiconductor light receiving element and surfaces of external connection terminals protruding into the cavity are provided. Then, the semiconductor light-receiving element was hermetically sealed in the cavity portion by connecting a lid made of glass, sapphire plate, or the like to the ceramic frame body. The electrical connection between the semiconductor light receiving element and the external circuit board is performed by connecting the external connection terminal protruding outside the package for housing the semiconductor light receiving element and the circuit board with solder, and through the external connection terminal. It has been broken. Such a package for housing a semiconductor light receiving element is required to have a structure capable of stably transmitting electric signals at high speed and capable of being manufactured at low cost.

  However, since the conventional package for housing a semiconductor light receiving element as described above needs to join the external connection terminal by heating the glass between the ceramic base and the ceramic frame, the thermal expansion coefficient is close to that of the ceramic. Since the external connection terminal made of expensive metal such as 42 alloy is required and the expensive Ni or Au plating film is provided relatively thickly, the package for housing the semiconductor light receiving element is very expensive. In addition, since the 42 alloy is made of an Fe—Ni alloy, there is a problem in the transmission speed of electric signals.

  A conventional external connection terminal for a package for housing a semiconductor light receiving element includes, for example, the name “lead frame for a semiconductor device” as disclosed in Patent Document 1, and a plurality of layers of metal on a Cu or Cu alloy material surface. A lead frame for a semiconductor device having a coating formed thereon is disclosed. In this lead frame for a semiconductor device, a Pd or Pd alloy film having a thickness of 0.3 μm or less is formed on the entire surface of the Cu or Cu alloy material via a Ni undercoat, and Pd formed on the outer lead of the lead frame. Alternatively, an Au plating film having a thickness of 0.001 to 0.1 μm is formed on the Pd alloy film. In this lead frame for a semiconductor device, a semiconductor element is placed on a lead frame for a die pad for bonding a semiconductor element, and one terminal of a lead frame provided close to the lead frame for the semiconductor element and the die pad After connecting them with a bonding wire, the other terminal portion of the lead frame is exposed to the outside and the whole is molded to obtain a semiconductor device.

Japanese Patent No. 2543619

However, the conventional semiconductor light receiving element storage package as described above has the following problems.
A package for housing a semiconductor light receiving element using an external connection terminal, which is a lead frame for a semiconductor device as disclosed in Japanese Patent No. 2543619, stably transmits electric signals at high speed by using Cu or a Cu alloy. Although it is possible to form an inexpensive external connection terminal with a relatively inexpensive Cu material and by thinning an expensive Au plating film, the external connection terminal is provided between the ceramic base and the ceramic frame. It is necessary to heat at about 500 ° C. to fix it with glass, and the difference in the thermal expansion coefficient between the ceramic and the external connection terminal becomes large, causing a problem in bonding reliability. An element storage package cannot be configured. Further, when Cu is used for the metal of the external connection terminal, since the strength (tensile strength, Vickers hardness, etc.) of Cu is low, the shape as the external connection terminal cannot be maintained, and the package for housing the semiconductor light receiving element is used. It can no longer be configured. Furthermore, when a Cu alloy is used for the metal of the external connection terminal, the strength of the Cu alloy can be obtained by limiting the metal to be contained in Cu, so not all of the Cu alloy can be used, but the metal to be added It is necessary to select

  SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and is a package for housing a semiconductor light receiving element that can stably transmit electric signals to an external connection terminal at high speed, and has a structure that is inexpensive and has high bonding reliability. The purpose is to provide.

The package for housing a semiconductor light receiving element according to the present invention that meets the above-mentioned object is substantially the same as the outer dimensions of the ceramic base that forms a flat ceramic base and a cavity that is bonded to the upper surface of the ceramic base and houses the semiconductor light receiving element. A window frame-shaped ceramic frame having the same outer dimensions, a lead terminal portion from the inner peripheral side of the ceramic frame interposed between the ceramic base and the ceramic frame, and from the outer peripheral side of the ceramic base and the ceramic frame In the package for housing a semiconductor light receiving element having lead frame-shaped external connection terminals that are fixed to each other with a bonding material made of an epoxy resin so that each of the external connection terminals is Cu 97 wt% or more, and the balance is Fe, P, Zn with a Cu alloy containing all the surface exposed to the outside at least the lead terminal portion 0.2 3.0μm thick Ni plating film on the surface of the Ni plating film 0.01~0.15μm thickness of Pd plating film, and Pd on the surface of the plated coating 0.003~0.02μm thickness of thin flash Au plating film Each of the three layers has a plating film formed by an electrolytic plating method .

  The semiconductor light receiving element storage package having the above structure has a semiconductor light receiving portion in a hollow portion of a cavity formed by a window frame-shaped ceramic frame having an external connection terminal interposed therebetween and having substantially the same external dimensions as the ceramic base. It has the effect | action that an element can be accommodated. The package for housing a semiconductor light receiving element includes a semiconductor light receiving element in which a plurality of external connection terminals made of a Cu alloy containing at least 97 wt% Cu and all of Fe, P, and Zn are contained in the cavity. An electric signal can be transmitted to the outer peripheral side of the package. Further, in this semiconductor light receiving element storage package, one lead terminal portion of the ceramic base, the ceramic frame, and the external connection terminal exposed to the cavity portion formed by fixing the external connection terminal with an epoxy resin is a bonding wire. It has the effect | action that it can be set as the connection pad part for electrically connecting with a semiconductor light receiving element via this. Then, the other lead terminal portion of the external connection terminal exposed on the outer peripheral portion side of the package is a circuit board, for example, an effect that it can be a joint portion for joining to a board or the like via solder or the like. Have.

  In addition, this semiconductor light receiving element storage package has a Ni plating film on the surface of each lead terminal part exposed at least outside the package and in the cavity part, a Pd plating film on the surface, and an Au plating film on the surface. By having a three-layer plating coating consisting of the bonding wire can be stably connected to one lead terminal portion exposed to the cavity portion side, and the other lead terminal portion exposed to the outer peripheral portion side of the package In addition, it has an effect that it can be stably bonded to the circuit board via solder or the like.

  In particular, the plating film is composed of three layers, and the Au plating film can be composed of a thin flash Au plating film having a thickness of 0.02 μm or less, and has a structure that can be manufactured at low cost while having sufficient wire bonding properties. It has the effect of being able to.

The semiconductor light-receiving element storage package according to claim 1 Symbol placement is substantially the same external and external dimensions of the ceramic base to form a cavity for accommodating the ceramic substrate of a flat plate shape, a semiconductor light receiving element is bonded to the upper surface of the ceramic substrate The window frame-shaped ceramic frame having a size, the lead terminal portion from the inner peripheral side of the ceramic frame interposed between the ceramic base and the ceramic frame, and the lead terminal portion from the outer peripheral side of the ceramic base and the ceramic frame, respectively In a semiconductor light receiving element storage package having a lead frame-shaped external connection terminal which is fixed by a bonding material made of an epoxy resin so as to protrude , the external connection terminal is 97% by weight or more of Cu, and the balance is Fe, P, Zn. with a Cu alloy containing, 0.2 to 3.0 [mu] m on the surface exposed to the outside at least the lead terminal portion Composed of three layers of Ni plating film, Ni 0.01～0.15Myuemu thickness of Pd plating film on the surface of the plating film, and the surface 0.003~0.02μm thickness of the thin flash Au plating film of Pd plating film Since each of them has a plating film formed by an electrolytic plating method, an epoxy resin that can be bonded at a low temperature of about 150 ° C. is used as a bonding material for fixing the ceramic substrate, the ceramic frame, and the external connection terminals. An external connection terminal made of a Cu alloy can be used even if the expansion coefficients are significantly different, and the Cu alloy contains at least 97% by weight of Cu and the remainder contains all of Fe, P, and Zn, and has high strength and is easy to handle. A package can be constructed, and electric signals can be transmitted stably and at high speed. The semiconductor light receiving element storage package is a plating composed of three layers: a relatively thin Ni plating film on the external connection terminal using a Cu alloy, a Pd plating film that can replace the thickness of the Au plating film, and a thin Au plating film. than ing from the configuration of providing the coating may be sufficient wire bondability to the external connection terminal, while securing the solderability, and low cost manufacturing can be structured. Furthermore, the Au plating film is made of a thin flash Au plating film having a thickness of 0.003 to 0.02 μm formed by an electrolytic plating method, and the Au plating film using expensive Au can be easily made thin and inexpensive. Package.

  The package for housing a semiconductor light receiving element can be easily configured by providing a Ni plating film, a Pd plating film, and an Au plating film in advance on the external connection terminals, and can be made into an inexpensive package. Alternatively, in the package for housing a semiconductor light receiving element, a joined body is formed before the plating film is provided on the external connection terminal, and the Ni plating film, the Pd plating film, and the Au plating film are formed on the external connection terminal exposed to the outside of the joined body. A package can be formed by providing a wire, and an expensive plating film is not provided on a portion that does not require wire bonding or soldering.

Subsequently, the best mode for carrying out the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.
Here, FIGS. 1A and 1B are a plan view and an AA ′ line enlarged vertical sectional view of a semiconductor light receiving element storage package according to an embodiment of the present invention, respectively.

  As shown in FIGS. 1A and 1B, a semiconductor light receiving element storage package 10 according to an embodiment of the present invention has a flat plate-like ceramic base 11 and substantially the same external dimensions as the ceramic base 11. A window frame-shaped ceramic frame body 12 having external dimensions and a plurality of lead frame-shaped external connection terminals 13 interposed between the ceramic base body 11 and the ceramic frame body 12 are configured. The semiconductor light receiving element storage package 10 stores a semiconductor light receiving element between an upper surface of a ceramic substrate 11 that is fixed by a bonding material 14 with an external connection terminal 13 interposed therebetween and an inner peripheral side wall surface of the ceramic frame body 12. A cavity portion 15 is formed. The semiconductor light receiving element storage package 10 leads the external connection terminals 13 from the inner peripheral side of the ceramic frame 12 to the inside of the cavity 15 and from the outer peripheral sides of the ceramic base 11 and the ceramic frame 12 to the outside of the package. The terminal portions are fixed so as to protrude.

The ceramic base 11 and the ceramic frame 12 are made of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), or the like, which is an example of ceramic. For example, ceramic powder such as Al ₂ O ₃ and a binder The granulated powder raw material prepared by drying the aqueous solution mixed with a spray dryer is press-molded into a desired size and shape using a powder press die consisting of an upper die, a lower die, and a die. After forming the formed body, each is formed into a fired body by firing at a high temperature of about 1550 ° C. in a firing furnace. Each fired body is cut and flattened by a surface grinder or the like to form a ceramic base body 11 or a ceramic frame body 12.

  In the semiconductor light receiving element storage package 10 described above, the bonding material 14 for fixing the ceramic base 11, the ceramic frame 12, and the external connection terminal 13 is made of an epoxy resin. The epoxy resin bonding material 14 can be fixed by heating and curing for about 1 hour at a low temperature of about 150 ° C. in a heating apparatus in the atmosphere. Therefore, the semiconductor light receiving element storage package 10 can be processed at a low temperature to fix the ceramic base 11 and the external connection terminal 13 having a coefficient of thermal expansion greatly different from that of the ceramic frame 12, which causes a problem in bonding reliability. It is possible to fix without causing. The fixing method of the ceramic base 11, the ceramic frame 12, and the external connection terminal 13 with the bonding material 14 is usually performed by first joining the ceramic base 11 and each external connection terminal 13 of the ceramic frame 12. Then, a paste-like epoxy resin before curing is screen-printed and dried to form a predetermined thickness. Next, the ceramic base 11, the external connection terminal 13, and the ceramic frame 12 are positioned and set in this order on the fixing jig, and then the above temperature and time are set using the above heating device. The semiconductor light receiving element storage package 10 is manufactured by heating and curing.

  In the semiconductor light receiving element storage package 10, the external connection terminal 13 is made of Cu alloy containing 97 wt% or more of Cu, and the balance is Fe, P, and Zn. It is to be noted that this Cu alloy is not preferable when the Cu content is less than 97% by weight because the transmission speed of the electric signal becomes slow. In addition, this Cu alloy has a total content of Fe, P, and Zn in the Cu alloy of 3% by weight or less, and the content of Fe is not particularly limited, but Fe is 2.1 to 2.6. It is preferable to contain within a range of wt%, P of 0.015 to 0.15 wt%, and Zn of 0.05 to 0.20 wt%. The external connection terminal 13 made of a Cu alloy having a content in the above range has high strength and elongation, maintains the shape of the lead terminal, is excellent in workability, and increases the transmission speed of electric signals. Can do. Moreover, this Cu alloy is excellent in corrosion resistance, and can form the external connection terminal 13 which can prevent especially generation | occurrence | production of stress corrosion cracking.

  The external connection terminal 13 is formed by patterning a plurality of lead terminals by etching or punching a plate metal plate made of Cu alloy, so that one of the plurality of lead terminals is directed toward the cavity 15. In this manner, the other lead terminal portion side is formed into a flat lead frame shape body provided with a tie bar portion (not shown) surrounding the outer periphery so as to be in a connected state. And, from this flat lead frame shape body, by bending the position that can remain in the flat plate shape or straddle one of the opposing width directions of the ceramic substrate 11, The external connection terminal 13 having a tie bar portion is formed.

  The semiconductor light receiving element storage package 10 has an Ni plating film 16 on the surface of the external connection terminal 13 exposed at least outside the lead terminal portion, a Pd plating film 17 on the surface of the Ni plating film 16, and the Pd plating film. A plating film 19 composed of three layers of an Au plating film 18 is formed on the surface 17 by an electrolytic plating method. The three-layer plating film 19 promotes the advantages of the respective plating films 16, 17, and 18 by the combined structure of the Cu alloy plate and the three-layer plating films 16, 17, and 18 covering the Cu alloy plate. However, the defect of each plating film 16, 17, 18 can be compensated. Each of the three plating films is not particularly limited in thickness, but the Ni plating film 16 thickness is not too thin to prevent oxidation of the Cu alloy and ensure solder wettability. It is necessary to have a thickness that can prevent the adhesiveness with the Cu alloy from being damaged due to the stress being not too thick. Further, the Pd plating film 17 is not too thin, so that the thin Au plating film 18 can be covered to prevent the wire bondability from being impaired. Thickness that can be prevented is required. Furthermore, it is necessary to prevent the package from becoming expensive by making the Au plating film 18 as thin as possible so that the wire bondability is not impaired.

  Here, the thickness of the Au plating film 18 of the semiconductor light receiving element storage package 10 is preferably a thin flash Au plating film of 0.02 μm or less. The thickness of each of the three plating films 16, 17, and 18 is preferably as follows: Ni plating film 16 thickness is 0.2 to 3.0 μm, and Pd plating film 17 thickness is 0.01 to 0. The thickness of the Au plating film 18 is preferably about 0.003 to 0.02 μm. With the combination of these, the package 10 for housing the semiconductor light receiving element can reduce the package while ensuring the required quality as a package for housing the semiconductor light receiving element.

  Although the semiconductor light receiving element storage package 10 is not shown, the external connection terminal 13 is provided with a Ni plating film 16, a Pd plating film 17, and an Au plating film 18 on a lead frame-shaped Cu alloy plate in advance. It may be. Alternatively, the semiconductor light receiving element storage package 10 has the ceramic base 11, the ceramic frame 12, and the external connection terminals before the three-layer plating film 19 is provided on the external connection terminals 13 as shown in FIG. The lead frame-shaped Cu alloy plate exposed to the outside of the joined body in which 13 is fixed with the joining material 14 is provided with a plating film 19 composed of three layers of a Ni plating film 16, a Pd plating film 17, and an Au plating film 18. It may be.

  The semiconductor light receiving element storage package of the present invention is equipped with a CCD type semiconductor light receiving element and can be used for a facsimile, a line scanner, an image scanner, and the like. Further, the semiconductor light receiving element housing package of the present invention is equipped with a MOS type semiconductor light receiving element and can be used for a digital camera, a digital video camera, or the like.

(A), (B) is a perspective view of the package for housing a semiconductor light receiving element according to an embodiment of the present invention, respectively, and is an enlarged vertical sectional view taken along line A-A ′.

Explanation of symbols

  10: Semiconductor light receiving element storage package, 11: Ceramic substrate, 12: Ceramic frame, 13: External connection terminal, 14: Bonding material, 15: Cavity, 16: Ni plating film, 17: Pd plating film, 18: Au plating film, 19: plating film

Claims (1)

A plate-shaped ceramic base body, and a window frame-shaped ceramic frame body having substantially the same external dimensions as the external dimensions of the ceramic base body that is bonded to the upper surface of the ceramic base body to form a cavity for housing a semiconductor light receiving element; An epoxy resin is provided between the ceramic base and the ceramic frame so that lead terminal portions protrude from the inner peripheral side of the ceramic frame and from the outer peripheral side of the ceramic base and the ceramic frame, respectively. in the semiconductor light-receiving element storage package having an external connection terminal of the lead frame shape fixed by bonding material made of the external connection terminal Cu97% by weight or more, made of a Cu alloy containing any Fe, P, Zn the remainder together, Ni plating 0.2~3.0μm thickness on the surface exposed to the outside of at least the lead terminal portion to be , Pd plating film of 0.01~0.15μm thickness on the surface of the Ni plating film and each consisting of three layers of thin flash Au plating film of 0.003~0.02μm thickness on the surface of the Pd plating film A package for housing a semiconductor light receiving element, comprising a plating film formed by an electrolytic plating method .

Images