JP3493791B2 - Semiconductor package having light transmission window and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor package having a light transmission window for accommodating an optical semiconductor element, and a method of manufacturing the same.

[0002]

2. Description of the Related Art When a light transmitting window is provided in a package containing an optical semiconductor element such as a light emitting element or a light receiving element, a conventional method has been to cover the light transmitting portion provided in a metal package body. First, the window material is bonded to the metal surface of the package body with a low melting point glass.

In this case, since the airtightness cannot be secured at the portion where the window material is joined to the window material of the package body and the low-melting glass, if the thermal expansion is not matched, sapphire or borosilicate glass is used as the window material. However, Kovar is used in at least the window material joining portion of the package body.

As a method of joining window materials without using a low melting point glass, for example, a package in which a plurality of metal or ceramic parts are joined is disclosed in Japanese Patent Laid-Open No. 54-14698.
As described in Japanese Patent Laid-Open No. 6, there is a method in which metallization is performed in advance on the bonding portion at the peripheral portion of the window material and the metallized portion of the window material and the package body are bonded with a brazing material or solder.

Further, as disclosed in JP-A-6-151629, a ceramic ring is bonded to a metal surface of a package body through a metallization layer, and a window material is bonded to the ceramic ring by using a low melting point glass. The method of doing is also proposed.

[0006]

SUMMARY OF THE INVENTION As described above, when a window material is bonded to a package body, a conventional method using a low melting point glass is used to improve the wettability of the low melting point glass. An oxide film is formed on the metal surface in advance, or an oxide film is formed on the package surface at the time of bonding. However, since the package is surface-plated after the window materials are joined, for example, Japanese Patent Laid-Open No. 61-42936.
As described in the publication, it was necessary to remove this oxide film after joining the window materials.

Further, after removing the oxide film, the package body is plated with nickel or gold for the purpose of improving the corrosion resistance. At this time, the low melting point glass bonding the window material is melted in the plating solution. As a result, the surface is deteriorated, the window material is contaminated, and fine particles mixed in the plating solution adhere to the window material.

In addition, in the method of joining the window material with the brazing material or the solder, inexpensive borosilicate glass cannot be used as the window material, and the window material is subjected to the metallizing treatment, which significantly increases the cost of the window material. There was a flaw. Moreover, if there is a scratch on the metallized portion, even a minute scratch will cause poor airtightness, so that much labor is required for quality control as compared with a window material without metallization.

In addition, according to the conventional method, if the thermal expansion is not matched between the window material joined with the low melting point glass, the brazing material or the solder, and the package body, the airtightness is secured by the difference in thermal expansion. Therefore, when sapphire or borosilicate glass is used for the window material, the package body is practically limited to Kovar, and the flexibility of selecting the material of the package body is extremely narrow.

In view of such conventional circumstances, the present invention eliminates the need to provide an oxide film on the package body or to remove the oxide film after joining when the window material is joined to the package body. The low melting point glass used for joining the materials does not melt into the plating solution for the surface plating or contaminates the window material, so the flexibility of selecting the material of the package body is wide, the airtightness is excellent, and the cost is low. It is an object of the present invention to provide a semiconductor package having a transparent window.

[0011]

In order to achieve the above object, a semiconductor package provided with a light transmitting window provided by the present invention has a metal frame member between a window member and a window member mounting portion of a package body. The metal frame member is provided with gold plating on the portion excluding the surface to be joined with the window material, and the metal frame member is joined to the window material with a low melting point glass, and the window material mounting portion of the package body having the surface plating is provided. It is characterized by being joined by a brazing material or solder.

In the method for manufacturing a semiconductor package having a light transmitting window according to the present invention, the metal frame member, which is gold-plated on a portion other than the bonding surface with the light transmitting window member, is made of a low melting point glass. After joining to the window member, the surface of the metal frame member opposite to the window member is joined by brazing or soldering to the window member attaching portion of the package which is surface-plated.

The method of the present invention will be described in detail with reference to FIG. First, a metal frame member 4 having an appropriate frame shape is prepared according to the shape of the window material 1 and the shape of the light transmitting window portion 3 provided on the window material mounting portion 2 of the package body, and the window of the metal frame member 4 is prepared. Gold plating 5 is applied in advance to the portion excluding the joint surface with the material 1. In this case, the joint surface with the window material 1 may be masked and plated, or after the entire surface is plated, the joint surface with the window material 1 may be removed. The gold plating 5 is not provided on the surface of the metal frame member 4 that is joined to the window member 1 because the presence of the gold plating 5 adversely affects the wettability and airtightness of the low melting point glass.

Next, the surface of the metal frame member 4 on the side where the gold plating 5 does not exist is bonded to the window member 1 with the low melting point glass 6. On the other hand, the window material mounting portion 2 of the package body is preliminarily subjected to ordinary surface plating. Finally, the window material 1 in the state of being bonded to the metal frame member 4 is bonded to the window material mounting portion 2 of the package body which has already been subjected to the surface plating. That is, the surface of the metal frame member 4 on the opposite side of the window member 1 is joined to the window member mounting portion 2 of the package body, which has been subjected to the surface plating, with the brazing material or the solder 7 to form the package having the light transmitting window. Obtainable.

[0015]

In the present invention, when the window material is joined to the package body, the metal frame portion is interposed, the metal frame portion and the window material are joined together with the low melting point glass, and the metal frame member is pre-plated. Since it is bonded to the package body, there is no need to immerse the package in the plating solution after the window material is bonded, and the low-melting glass used for bonding the window material is prevented from touching and melting the plating solution for surface plating. Therefore, it is not necessary to remove the oxide film on the package.

Further, if the thermal expansion is matched among the window material, the metal frame member and the low melting point glass, the material of the window material mounting portion of the package body is matched with the window material and the low melting point glass in the thermal expansion. It is not necessary to take it, and any material that can be joined to the metal frame portion by brazing or soldering may be used. Therefore, the window material mounting portion of the package body can be widely selected from metals, ceramics, etc. without any problem even if there is a flow of brazing material or solder.

Further, in the present invention, since it is not necessary to metallize the window material and the like, it is possible to suppress an increase in cost, and at the same time, the occurrence of airtightness failure due to scratches on the metallization is eliminated, which is a point of quality control. But it is advantageous.

[0018]

EXAMPLE A package for an LD module was produced by the following three processes according to the method of the present invention. The window material mounting portion of this package was made of Kovar, and the window material to be mounted on this package was a sapphire or borosilicate glass window material having a diameter of 3.5 mm. Also, diameter 4mm, thickness 0.5mm
A through hole having a diameter of 2 mm was formed on the Kovar plate as a light transmitting window to obtain a metal frame member.

Sample 1 was manufactured by the following process.
That is, Ni plating was applied to the entire surface of the Kovar metal frame member, and a gold plating having a thickness of 2 μm was formed thereon, and then the gold plating on one surface was polished and removed, and acid cleaning was performed.
After that, the borosilicate glass window material was
It is bonded to a metal frame member at 50 ° C., and this metal frame member is further bonded to the window member mounting portion of the package by using an Au / si brazing material.
Bonded at 0 ° C.

Sample 2 is a metal frame member joined to a window member in the same procedure as in Sample 1, and is made of Pb / Sn brazing material for 200 times.
Bonded to the window material mounting part of the package at ℃. Also, sample 3
Was manufactured in the same procedure as in Sample 1, except that a sapphire window material was used instead of the borosilicate glass window material.

Ten samples were prepared for each sample, the initial airtightness was measured, and a thermal shock test at -50 ° C to 150 ° C was conducted.
The airtightness after 0 cycles was measured, and the obtained results are shown in Table 1. The airtightness of the packages of all the samples was 10 ^-10 cc / sHe or less, which was a level at which there was no problem, and no change was observed after thermal shock.

[0022]

[Table 1]

[0023]

According to the present invention, since it is not necessary to immerse the package in the plating solution after the window materials are joined, the low melting point glass used for joining the window materials may come into contact with the plating solution and melt.
The window material is not contaminated by fine particles in the plating solution. Moreover, there is no need for subsequent plating, and since the surface of the gold plating applied to the metal frame member is not oxidized even in an oxidizing atmosphere, there is no need to remove the oxide film.

Further, if the thermal expansion is matched among the window material, the metal frame member and the low melting point glass, the material of the window material mounting portion of the package body is the thermal expansion joint with the window material or the low melting point glass. It is not necessary to take it, as long as it is a material that can be joined to the metal frame portion by brazing or soldering, the degree of freedom in designing, such as selection of the package material, is greater than in the past.

Further, since it is not necessary to perform metallization on the window material and the like, it is possible to suppress an increase in cost, and at the same time, since the problem of airtightness due to metallization is eliminated, quality control can be simplified. is there.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a specific example of a package of the present invention.

[Explanation of symbols]

1 window material 2 Window material mounting part of the package body 3 Light transmitting window 4 metal frame members 5 gold plating 6 Low melting glass 7 Brazing material or solder

Continuation of the front page (56) Reference JP-A-6-318647 (JP, A) JP-A-6-151629 (JP, A) JP-A-62-273768 (JP, A) JP-A-54-146986 (JP , A) JP-A-62-29149 (JP, A) JP-A-62-20358 (JP, A) JP-A-5-304434 (JP, A) Actually-laid-open Hei 2-132953 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 23/02 H01L 31/02

Claims (3)

(57) [Claims] 1. A metal frame member is provided between a window member and a window member mounting portion of a package body, and the metal frame member is gold-plated at a portion excluding a joint surface with the window member, and the metal frame member is a window. A semiconductor package having a light-transmissive window, which is joined to a window material mounting portion of a package body provided with a low melting point glass and a package body having a surface plating by a brazing material or solder. 2. The semiconductor package according to claim 1, wherein the metal frame member is made of Kovar, and the window material is made of sapphire or borosilicate glass. 3. A surface of the metal frame member opposite to the window material after bonding a metal frame member plated with gold to the window material with a low melting point glass except for a surface to be bonded to the light transmitting window material. A method for manufacturing a semiconductor package having a light-transmissive window, characterized in that the above is bonded to a window material mounting portion of a package body that has been subjected to surface plating by brazing or soldering.