JPH09246440A - Manufacture of package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce warping caused by soldering a radiation board, by dividing a soldering process into two steps, that is, performing hard soldering of a case, a ceramic terminal and a lead, and soft soldering of a radiation board made of a W-group sintered alloy. SOLUTION: First, Au/Ni plating is performed on a radiation board 4. Then, a case 2, a ceramic terminal 3, a lead 5 and a seal ring 6 are heated and hard-soldered, using a foil of silver solder at junction parts. In addition, Au/Ni plating is performed on this silver-soldered assembly member. Next, an AuGe solder material is used between the assembly member and the radiation board 4, and heating and soft soldering are performed. Thus, since the soldering temperature of the radiation board 4 is a low temperature, warping caused by soldering of the radiation board 4 may be reduced. Also, by grinding the outer surface of the hard-soldered radiation board 4 made of a W-group sintered alloy, warping of the radiation board 4 caused by hard soldering may be reduced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method of manufacturing a package such as an optical module using a semiconductor.

[0002]

2. Description of the Related Art FIG. 2 shows a butterfly type optical module package as an example of an optical module package used in an optical communication device. Usually, this butterfly type optical module package 1 comprises a case 2, a ceramic terminal 3, a heat sink 4, leads 5 and a seal ring 6 as main constituent members. Case 2 is package 1
Has a role as a base material for shaping the outer shape, storing the internal parts, and joining with the ceramic terminal 3 and the optical fiber holder (not shown). The heat dissipation plate 4 forms the bottom of the package 1, and has a role of efficiently radiating the heat generated inside the package 1 to the outside. The ceramic terminal 3 has a wiring formed of Au or the like on an insulating ceramic and has a role of introducing a current from the outside to the inside of the package 1. One end of each wiring of the ceramic terminal 3 is arranged inside the package 1, and the other end thereof is arranged outside. The lead 5 is usually made of metal, and the package 1 of the ceramic terminal 3 is used.
Is joined to the outer side of. The lead 5 is used for electrical connection with a printed circuit board or the like. Usually, the material is
The case 2 is made of Kovar (FeNiCo alloy), the heat dissipation plate 4 is made of CuW, the ceramic terminals 3 are made of alumina, and the leads 5 are made of Kovar.

The package 1 is assembled as follows. That is, 1) First, each member is subjected to silver brazing pretreatment. That is,
The heat dissipation plate 4 made of CuW is plated with Ni. Also,
The ceramic terminal 3 made of alumina has W or Mo.
Mn metallization and Ni plating are applied. The case 2 made of Kovar and the lead 5 are plated with Ni. 2) Then, these components are assembled with silver brazing material, and heated and hard brazed. 3) The assembled package 1 is usually Au / Ni plated. This plating treatment is for improving the wettability of the solder material and the bonding bondability, and the thickness of the Au plating layer is set to 1 μm or more. 4) Further, a window made of a material such as sapphire may be brazed to the case pipe portion 7 if necessary. This bonding method is usually AuGe, Au.
Soft brazing of Si, AuSn or the like, or joining with a low melting point glass is used.

By the way, the heat sink 4 of the package 1 is
Usually, a screw hole 8 for fixing the package 1 to a printed circuit board or the like is provided. However, when the package 1 is screwed, there is a drawback that the screw hole 8 of the heat dissipation plate 4 made of CuW material or its vicinity is easily broken. This occurs because CuW, which is the material of the heat dissipation plate 4, has a brittle property.

Therefore, the heat dissipation plate 4 contains Ni and Fe,
Further, a technique is disclosed in which Mo is contained as necessary, and the rest is composed of a W-based sintered alloy having a composition of W and inevitable impurities (see Japanese Patent Laid-Open No. 3-2265411). This alloy has higher tensile strength, higher elongation, and flexibility as compared to CuW. This alloy is also a material that can be formed into a desired shape by a metal injection molding method and can be processed at a low cost by largely omitting machining.

[0006]

However, when the heat dissipation plate is made of the above W-based sintered alloy, there are the following problems. That is, this alloy has an average coefficient of thermal expansion slightly smaller than that of CuW and is 4 to 6 × 10 ⁻⁶ / ° C., and when hard brazing such as silver brazing is performed, the heat dissipation plate is slightly warped due to thermal stress. There was a problem.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the invention according to claim 1 is a method of manufacturing a package having a heat sink, a case, ceramic terminals and leads. In a method of manufacturing a package, which comprises a W-based sintered alloy having a composition in which the heat sink contains Ni, Fe, and optionally Mo, and the balance is W and inevitable impurities, a case, a ceramic terminal, and Hard brazing the leads, and Au / N on the hard brazed case, ceramic terminals and leads.
i-plating step, Au / Ni plating step on heat sink, hard brazing case, ceramic terminals and leads, and soft brazing step on the plated heat sink It is characterized by that.

According to a second aspect of the present invention, there is provided a method of manufacturing a package having a heat dissipation plate, a case, a ceramic terminal and a lead, wherein the heat dissipation plate contains Ni, Fe and, if necessary, Mo. In the method of manufacturing a package made of a W-based sintered alloy having the composition of the balance W and unavoidable impurities, a step of hard brazing the heat radiating plate, the case, the ceramic terminals and the leads, and the heat radiating by the hard brazing. The method is characterized by including a step of plating the plate, the case, the ceramic terminal and the lead with Au / Ni and a step of grinding the outer surface of the heat dissipation plate plated with Au / Ni.

As described in claim 1, the brazing process is divided into two steps, and the case, the ceramic terminals, and the leads are hard brazed with silver brazing or the like, and the heat dissipation plate made of the above W-based sintered alloy is obtained. When soft brazing is performed using AuGe, AuSi, AuSn, or the like, the heat radiation plate is brazed at a low temperature, so that the warpage caused by the heat radiation plate can be reduced.

When the outer surface of the heat radiating plate made of the above-mentioned W-based sintered alloy that has been hard brazed is ground as described in claim 2, the warp of the heat radiating plate caused by the hard brazing is reduced. be able to. The W-based sintered alloy described above is easy to grind and does not chip or break during grinding. Also, when grinding is performed, the outer surface of the heat sink is free of Au / Ni plating.
Since the base sintered alloy has sufficient corrosion resistance, there is no risk of damage to the package due to corrosion.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a package manufacturing method according to the present invention will be described in detail below. First, a case (kovar), a ceramic terminal (alumina), a seal ring (kovar), a lead (kovar), a heat sink, and a window (sapphire) are prepared as package members. The case is formed into a desired shape by metal injection molding and machining. The ceramic terminals are formed by the green sheet method to form the wiring inside by using W paste, and the green body is formed and fired. M
It is manufactured by applying oMn metallization and Ni plating.
The seal ring is manufactured by pressing a Kovar plate. The leads are produced by etching a Kovar plate.
The window is produced by cutting and polishing a sapphire single crystal, subjecting the joined portion to a deposition metallization treatment of Au / Ni / Cr, and depositing an antireflection film on the central portion. The heat sink is injection-molded by a metal injection molding method with W powder, Ni powder, and Fe powder each having an average particle diameter of 5 μm or less, and particularly liquid-phase sintered at a temperature of 1500 ° C. or more to obtain a desired shape. obtain. WNiFe (Ni3wt% -Fe1.
5wt%) The average grain size of the grains containing W as the main component is 15
２５25 μm. Further, this sintered alloy is machined to obtain a heat sink having a desired shape. The members thus manufactured were assembled by the method shown in the following examples to manufacture a package.

[0012]

Embodiments of the method of manufacturing a package using the above-described members will be described below by changing the assembling process. (Embodiment 1) FIG. 1 is an explanatory view of a manufacturing process of this embodiment.
Step 1. The heat sink 4 was plated with Au / Ni. The bottom surface (30 mm x 12.7 mm) of the obtained heat sink was inspected in advance using a thickness gauge on the surface plate, and the warp was 20.
It was confirmed to be less than μm. Step 2. The case 2, the ceramic terminal 3, the lead 5, and the seal ring 6 are assembled with a carbon jig by sandwiching a silver brazing (BAg-8) foil in the joint portion, fixedly held, and then by a continuous belt furnace. It was heated to about 810 ° C and brazed. Further, the assembly member brazed with silver was plated with Au / Ni. Step 3. Next, an AuGe brazing material is sandwiched between the assembly member and the heat dissipation plate 4, held and fixed by a carbon jig, and heated to about 370 ° C. in a continuous belt furnace to soften the assembly member and the heat dissipation plate. Brazed Step 4. Furthermore, after this, the window 9 is attached to the pipe portion 7 of the case.
Soft brazing was performed using uSn brazing material.

(Second Embodiment) Steps 1 to 3 are the same as in the first embodiment. Step 4 of Example 1 is omitted and no window is provided. This example was performed in order to see the influence of the presence or absence of brazing of the window on the warp of the heat sink, as compared with the first example.

(Example 3) Steps 1 and 2 are the same as in Example 1. Step 3. An AuSi brazing material was sandwiched between the assembly member and the heat sink, held and fixed by a carbon jig, and heated to about 400 ° C. in a continuous belt furnace to softly braze the assembly member and the heat sink. Step 4 is the same as in Example 1. This example was performed in order to see the influence of the difference in the brazing material for soft brazing the heat dissipation plate, as compared with the first example.

Example 4 Steps 1 and 2 are the same as in Example 1. Step 3. An AuSi brazing material was sandwiched between the assembly member and the heat dissipation plate, and the assembly member and the heat dissipation plate were softly brazed. Step 4 of Example 1 is omitted and no window is provided. This example was performed in order to see the influence of the difference in the brazing material to be soft brazed on the heat dissipation plate, as compared with the second example.

(Example 5) Steps 1 and 2 are the same as in Example 1. Step 3. Au window on the pipe part of the case
Soft brazing was performed with a Ge brazing material. Step 4. An AuSn brazing material is sandwiched between the assembly member and the heat sink formed in step 3, held and fixed by a carbon jig, and heated to about 300 ° C in a continuous belt furnace to soften the assembly member and the heat sink. Brazed This embodiment is different from the first embodiment in that the heat radiating plate is brazed after the window is brazed.

Example 6 Steps 1 and 2 are the same as in Example 1. Step 3. Au window on the pipe part of the case
Si brazing material was soft brazed. Step 4 is the same as in Example 5. In this embodiment, the brazing material for brazing the window is different from that in the fifth embodiment.

(Embodiment 7) This embodiment is the same as Embodiment 5 except that Step 3 is omitted from Embodiment 5 and the window is not brazed.

(Embodiment 8) Step 1. The heat sink was plated with Ni. The bottom surface (30 mm × 12.7 mm) of the obtained heat dissipation plate was previously inspected on a surface plate using a thickness gauge, and it was confirmed that the warp was 20 μm or less. Step 2. The case, the ceramic terminal, the seal ring, the lead, and the heat sink are sandwiched with a silver brazing (BAg-8) foil at the joint portion, assembled using a carbon jig, fixedly held, and then held together by a continuous belt furnace. It was heated to 810 ° C and brazed. Further, the hard brazed assembly member was plated with Au / Ni. Step 3. Using the bottom surface of the heat sink as a temporary reference surface, the seal ring brazed to the upper side of the case was subjected to surface grinding, and the bottom surface of the heat sink was subjected to surface grinding using this seal ring surface as a reference surface. Step 4. The window was softened with AuSn on the case pipe.

Next, the following comparative example was manufactured. Step 1. The heat sink was plated with Ni. The bottom surface (30 mm × 12.7 mm) of the obtained heat dissipation plate was previously inspected on a surface plate using a thickness gauge, and it was confirmed that the warp was 20 μm or less. Step 2. The case, the ceramic terminal, the seal ring, the lead, and the heat sink are sandwiched with a silver brazing (BAg-8) foil at the joint portion, assembled using a carbon jig, fixedly held, and then held together by a continuous belt furnace. It was heated to 810 ° C and brazed. Further, the hard brazed assembly member was plated with Au / Ni. Step 3. The window was softened with AuSn on the case pipe. This comparative example is the same as Example 8 except that the bottom surface of the heat sink is not ground.

Next, 40 packages each were manufactured by the manufacturing methods of these Examples and Comparative Examples, and the warped state was inspected. In this inspection, the bottom surface of the package (that is, the bottom surface of the heat sink) was examined on a surface plate by using a thickness gauge to determine whether the warp was 20 μm or less. as a result,
For Examples 1-8, all packages were 20μ
The warp was less than m. On the other hand, for the comparative example, 40
Among them, 14 showed a warp exceeding 20 μm.

[0022]

As described above, according to the package manufacturing method of the first aspect, the step of brazing the case, the ceramic terminals and the leads, and the step of brazing the case, the ceramic terminals and the leads. A step of applying Au / Ni plating, a step of applying Au / Ni plating to the heat dissipation plate, a step of soft brazing the hardened case, the ceramic terminals and the leads, and the plated heat dissipation plate. Therefore, there is an excellent effect that it is possible to prevent the heat dissipation plate forming the bottom of the package from warping. Further, according to the package manufacturing method of claim 2,
A step of hard brazing the heat sink, the case, the ceramic terminals and the leads; a step of plating the hard brazed heat sink, the case, the ceramic terminals and the leads with Au / Ni; and a step of applying the Au / Ni plating. And the step of grinding the outer surface of the heat dissipation plate. Therefore, there is an excellent effect that the warp of the heat dissipation plate forming the bottom of the package can be prevented.

[Brief description of drawings]

FIG. 1 is a process explanatory view of an embodiment of a package manufacturing method according to the present invention.

FIG. 2 is an explanatory diagram of a package.

[Explanation of symbols]

 1 Package 2 Case 3 Ceramic Terminal 4 Heat Sink 5 Lead 6 Seal Ring 7 Case Pipe 8 Screw Hole 9 Window

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masayuki Sakamoto 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (2)

[Claims] 1. A method of manufacturing a package having a heat radiating plate, a case, a ceramic terminal and a lead, wherein the heat radiating plate contains Ni, Fe, and optionally Mo, and the rest is W and inevitable impurities. In a method of manufacturing a package made of a W-based sintered alloy having a composition of, a step of hard brazing a case, a ceramic terminal and a lead, and Au / Ni plating on the hard brazed case, the ceramic terminal and the lead. The process of applying and the heat sink A
A method of manufacturing a package, comprising: a step of applying u / Ni plating; a step of hard brazing the case, a ceramic terminal and a lead; and a step of soft brazing the plated heat dissipation plate. 2. A method of manufacturing a package having a heat dissipation plate, a case, a ceramic terminal and a lead, wherein the heat dissipation plate contains Ni, Fe, and optionally Mo, and the rest is W and inevitable impurities. In a method of manufacturing a package made of a W-based sintered alloy having a composition of, a step of hard brazing a heat radiating plate, a case, a ceramic terminal and a lead, and the hard radiating plate, a case, a ceramic terminal and a lead A method of manufacturing a package, comprising: a step of applying Au / Ni plating to the metal; and a step of grinding the outer surface of the heat dissipation plate plated with Au / Ni.