JP2550489Y2 - Lead frame - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a lead frame, and more particularly to an improvement of a structure of a lead frame used for a package for housing a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, a package for accommodating a semiconductor element, particularly a semiconductor element, for accommodating a semiconductor integrated circuit element is made of an electrically insulating material such as alumina ceramics as shown in FIGS. Molybdenum (Mo), tungsten (W), insulating base 11 having a metallized metal layer 12 made of a high melting point metal powder such as manganese (Mn), and the metallized metal for electrically connecting a semiconductor element to an external electric circuit. An external lead terminal 13 made of Kovar metal (Fe-Ni-Co alloy) or 42 alloy (Fe-Ni alloy) brazed to the layer 12 via a brazing material 14 such as silver brazing, and a lid 15. The semiconductor device 16 is housed inside an insulating container including the insulating base 11 and the lid 15, and the container is hermetically sealed to provide a semiconductor device.

In the conventional package for housing a semiconductor element, when the external lead terminals 13 are brazed to each of the metallized metal layers 12 provided on the insulating base 11, the workability of the brazing is facilitated. When plating a metal layer having excellent corrosion resistance on the outer surface of the lead terminal 13 by plating, in order to improve the workability of the layering, and further, when transporting the semiconductor element storage package, the external lead terminal In order to prevent external force from being applied to the external lead terminal 13 and deforming the external lead terminal 13 due to the external force, each external lead terminal 13
4 As shown in the figure, one end is commonly connected to a strip-shaped metal member 17, whereby the external lead terminal 13 is brazed to the insulating base 11 and a plated metal layer is formed on the outer surface of the external lead terminal 13. Workability of layering is greatly improved, and deformation during transportation is effectively prevented.

The external lead terminals 13 are formed by forming an ingot (a lump) of Kovar metal or the like into a thin plate by a conventionally known rolling process and punching it into a predetermined shape by a metal punching process. The metal member 17 connected to one end of the terminal 13 is also the external lead terminal 13.
Is formed at the same time as the formation.

[0005]

[Problems to be solved by the invention] However, recently,
In semiconductor device storage packages, the density of semiconductor elements housed therein has become higher and higher, and the number of external lead terminals used in the package has become extremely large. Each external lead terminal has a narrow line width. , And the thickness is becoming thinner. Therefore, the metal member formed at the same time as the external lead terminal is also extremely thin, and the mechanical strength is greatly reduced. Therefore, in this conventional package for housing semiconductor elements, when an external force is applied to the metal member during transportation or the like, the metal member is easily deformed by the external force, and as a result, the external lead terminals connected to the metal member Has a drawback that the external lead terminals cannot be connected accurately and reliably to an external electric circuit.

[0006]

According to the present invention, there is provided a lead frame in which one end of a plurality of external lead terminals is commonly connected to a band-shaped metal member, the band-shaped metal member reinforcing the band-shaped metal member outside thereof. A metal reinforcing member in the form of a frame is joined via a joint arm.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 shows an embodiment of a lead frame according to the present invention. The lead frame indicated generally by 1 comprises a plurality of external lead terminals 2 and a metal member 3.

The external lead terminal 2 serves to electrically connect the semiconductor element housed in the insulating base of the semiconductor element housing package to an external electric circuit, and one end thereof is provided on the outer surface of the insulating container. The metallized metal layer to which the electrode of the semiconductor element is connected is brazed through a brazing material such as silver brazing.

The other ends of the plurality of external lead terminals 2 are commonly connected to a metal member 3 at the other end, and the metal member 3 regulates the position of each of the external lead terminals 2. The effect of improving the workability when brazing the metal to the metallized metal layer of the insulating container and the workability when depositing a metal having excellent corrosion resistance on the outer surface of the external lead terminal 2 by plating is provided.

The connection of the external lead terminals 2 to the metal member 3 is such that the distance between adjacent external lead terminals 2 corresponds to the distance between the metallized metal layers provided on the insulating container.

Each of the external lead terminal 2 and the metal member 3 is made of a metal such as Kovar metal or 42 alloy. An ingot (lumps) of Kovar metal or the like is formed into a thin plate shape by rolling and has a predetermined shape by metal stamping. Formed at a time by punching.

The metal member 3 constituting the lead frame 1 is provided with a frame-shaped metal reinforcing member 4 on the outside thereof so that the frame-shaped portion 4a is arranged at a distance from the metal member 3. The metal reinforcing member 4 is joined to the four corners of the metal member 3 by, for example, spot welding or the like via the joint arm 4b to reinforce the decrease in mechanical strength due to the thinner thickness of the metal member 3. Then, even if an external force is applied to the metal member 3, the metal member 3 acts so as not to be deformed by the external force.

The metal reinforcing member 4 may be a metal material having sufficient mechanical strength to reinforce the mechanical strength of the metal member 3. For example, the metal reinforcing member 4 may be made of the same metal material as the metal member 3. If it does, the thickness is
The thickness of the frame-shaped portion 4a is at least 0.25 mm and the width of the frame-shaped portion 4a is at least 2.0 mm.

When the metal reinforcing member 4 is made of the same metal material as the metal member 3, the thickness thereof is smaller than that of the metal member 3.
When the thickness is less than 0.25 mm, and when the width of the frame-shaped portion 4a is less than 2.0 mm, a large mechanical strength is not obtained and the metal reinforcing member 4 tends to not function as a reinforcing member. 0.25m to the thickness of metal member 3
m or more, and the width of the frame-shaped portion 4a is preferably set to 2.0 mm or more.

The metal reinforcing member 4 is made of a metal material, and a frame-shaped portion 4a is formed on the outside of the metal member 3.
When the metal layer having excellent corrosion resistance is layered on the outer surface of the external lead terminal 2 by the electrolytic plating method since it is bonded via the bonding arm 4b so as to be arranged at an interval from 3,
The charged particles of the electrolytic plating are concentrated on the end of the metal member 3 and a large amount of plating metal tends to precipitate at the connection portion of the external lead terminal 2 with the metal member 3.
Effectively prevented by the external lead terminal 2
It is possible to deposit a plated metal layer having a substantially uniform thickness over the entire outer surface.

Next, a method of manufacturing a package for housing a semiconductor element using the lead frame of the present invention will be described with reference to an example shown in FIG.

First, a lead frame in which an insulating base 5 and a large number of external lead terminals 2 constituting an insulating container for accommodating a semiconductor element as shown in FIG.
Prepare 1

The insulating substrate 5 has a plurality of metallized metal layers 6 on its upper surface. The insulating substrate 5 having the metallized metal layers 6 is a green ceramic sheet (green sheet) having a surface coated with a metal paste by printing. ) In a reducing atmosphere (in H ₂ -N ₂ gas), about 1400
It is formed by firing at a temperature of ~ 1600 ° C.

The unsintered ceramic sheet is prepared by mixing a ceramic raw material powder such as alumina (Al ₂ O ₃ ) and silica (SiO ₂ ) with a suitable solvent and solvent to form a slurry, which is conventionally known. It is formed by forming into a sheet shape by a doctor blade method.

The metal paste is prepared by adding a suitable solvent and a solvent to a high melting point metal powder such as tungsten, molybdenum, manganese or the like, and mixing the powder with a conventionally known thick film method such as screen printing on the surface of the unfired ceramic sheet. Print applied.

The lead foom 1 in which the plurality of external lead terminals 2 are connected to a metal member 3 is made of a metal such as Kovar metal or 42 alloy, and is made of an ingot (e.g., Kovar metal).
The lump is formed into a predetermined thickness and a predetermined shape by a conventionally known rolling method and punching method.

Next, the insulating base 5 having the metallized metal layer 6 and the lead frame 1 having the external REIT terminal 2 are set in a jig (not shown) made of carbon, and the metallized metal layer 6 provided on the insulating base 5 is set. Positioning is performed such that one end of the external lead terminal 2 is placed on the exposed portion of this via a brazing material 7 such as silver brazing.

In this case, one end of each external lead terminal 2 is connected to the metal member 3, and since the position is regulated, all the external lead terminals 2 are connected to the metallized metal layer 6 provided on the insulating base 5. Positioning can be performed at once and easily.

And then the insulating substrate aligned as described above.
5 and the lead frame 1 are passed through a furnace heated to a temperature of about 900 ° C., and the external lead terminal 2 is brazed to the metallized metal layer 6 by heating and melting the brazing material 7.

Finally, a metal having excellent corrosion resistance such as nickel (Ni) or gold (Au) is deposited on the outer surface of the external lead terminal 2 brazed to the metallized metal layer 6 by electrolytic plating. As a result, a semiconductor element storage package as a product is completed.

In this case, since one end of each of the external lead terminals 2 is commonly connected to the metal member 3, all the external lead terminals can be connected only by connecting an electrode for electrolytic plating to the metal member 3. Second, the electric field for plating can be applied in common, and the workability of electrolytic plating becomes extremely easy.

Outside the metal member 3, a frame-shaped metal reinforcing member 4 is joined via a joint arm 4b such that the frame-shaped portion 4a is arranged at an interval from the metal member 3. As a result, the charged particles during the electroplating do not concentrate on the end of the metal member 3, and as a result, the plating metal layer is uniformly formed on the outer surface of the external lead terminal 2 which is commonly connected to the metal member 3. It becomes possible to layer on the thickness.

Further, in the completed package for storing a semiconductor element, a metal reinforcing member 4 is joined to the outside of a metal member 3 constituting the lead frame 1, so that the metal member 3 has a high mechanical strength. When transporting the semiconductor element storage package, the metal member 3 is not deformed even if an external force is applied to the metal member 3.
As a result, the external lead terminals connected to the metal member 3
As a result, the external lead terminal can be accurately and reliably connected to a predetermined external electric circuit.

[0029]

According to the lead frame of the present invention, one end of each external lead terminal is commonly connected to a metal member, and since its position is regulated, the external lead terminal is located outside the insulating container for housing the semiconductor element. When the external lead terminals are individually brazed to each of the metallized metal layers provided on the surface, the positions of each metallized metal layer and the external lead terminals can be aligned at one time, making the work of brazing the external lead terminals extremely easy. Becomes

Further, since each external lead terminal is commonly connected to a metal member, when a metal having excellent corrosion resistance is layered on the outer surface of the external lead terminal by electrolytic plating, the electrode for electrolytic plating is formed of a metal. The electric field for plating can be applied in common to all the external lead terminals simply by connecting to the member, and the workability of depositing the corrosion-resistant metal becomes extremely easy.

Further, since the frame-shaped metal reinforcing member is joined to the outside of the metal member via the joint arm so that the frame-shaped portion is arranged at a distance from the metal member, charged particles of electrolytic plating are provided. Does not concentrate on the end of the metal member, and as a result, a plated metal layer can be deposited to a uniform thickness on the outer surface of the external lead terminal commonly connected to the metal member.

Further, a metal reinforcing member is joined to the outside of the metal member, and the mechanical strength of the metal member is high, so that an external force is applied to the metal member when transporting a semiconductor device housing package or the like. Even if it is done, the metal member does not deform, and as a result, the external lead terminal connected to the metal member does not deform at all, so that the external lead terminal can be accurately converted to a predetermined external electric circuit.
And it can also be connected securely.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a lead frame of the present invention.

FIG. 2 is an exploded cross-sectional view for explaining a method for manufacturing a semiconductor device housing package using the lead frame shown in FIG. 1;

FIG. 3 is a cross-sectional view of a semiconductor element housing package manufactured using a conventional lead frame.

FIG. 4 is a plan view of a conventional lead frame.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lead frame 2 ... External lead terminal 3 ... Metal member 4 ... Metal reinforcing member 4a ... Frame-shaped part 4b ... Joining arm

Claims (2)

(57) [Scope of request for utility model registration] 1. A lead frame having one end of a plurality of external lead terminals commonly connected to a band-shaped metal member.
A lead frame, wherein a frame-shaped metal reinforcing member for reinforcing the band-shaped metal member is joined to the outside of the band-shaped metal member via a joint arm . Wherein said frame form of the metallic reinforcing member is thicker than 0.25mm than the thickness of the belt-shaped metal member, the lead frame according to claim 1, characterized in that it and a width of 2.0 mm or more.