JP2006216868A - Manufacturing method of semiconductor package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a product of high accuracy of finished dimension with good yield in which, when a frame body is brazed to a base plate, a ceramic terminal attached to the frame body can be brazed without dislocating. <P>SOLUTION: A method for manufacturing a semiconductor package includes a step for arranging a brazing filler material between the brazing surface of the frame body 12 and the brazing surface of the ceramic terminal 14 attached to a notch 12a formed in the frame body, and a base plate 10 to which these brazing surfaces are bonded; and a step for heating up to the temperature where the brazing filler material melts while applying a load in a direction clamping the base plate 10 and the frame body 12, to braze the base plate 10 to the frame body 12 and the ceramic terminal 14. The brazing filler materials 16a and 16b are arranged to a position, which does not overlap with the attaching position of the ceramic terminal 14 attached to the frame body 12, of the brazing surface of the frame body 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a semiconductor package, and more particularly to a method for manufacturing a semiconductor package formed by brazing a metal frame on a metal base plate.

  A semiconductor package mounting a high-frequency semiconductor element used in optical communication or microwave communication is formed by brazing a metal frame 12 to a metal base plate 10 as shown in FIG. There is a product called a metal wall package (for example, see Patent Document 1). The frame 12 is provided with a notch 12a, and a ceramic terminal 14 is attached to the notch 12a. The ceramic terminal 14 is for electrically connecting a semiconductor element mounted in the cavity and external wiring.

The base plate 10 is made of metal such as copper-molybdenum-copper or iron-nickel-cobalt alloy, and the frame 12 is made of metal such as iron-nickel-cobalt alloy or iron-nickel alloy.
When manufacturing a semiconductor package, the base plate 10, the frame body 12, and the ceramic terminal 14 are assembled to an assembly jig, and the frame body 12 and the base plate 10 and the brazed surface of the frame body 12 are assembled. A brazing material (preform) such as silver brazing formed in the same frame shape is placed, heated to a temperature at which the brazing material melts in a heating furnace, and attached to the base plate 10, the frame body 12, and the frame body 12. It is obtained by airtightly brazing the brazed surface of a ceramic terminal.
JP 2001-168220 A

In the semiconductor package, when the frame body 12 is brazed and joined to the base plate 10, a hole may be formed in the brazed portion or a gap defect may occur. In order to solve such a problem, A method of brazing while applying a load to the frame body 12 is performed.
However, if a preform of a brazing material is sandwiched between the base plate 10 and the frame body 12 and brazing is performed while applying a load to the frame body 12, the base plate 10 and the frame body 12 are heated to the brazing temperature. There is a problem that the ceramic terminal 14 attached to the frame body 12 is displaced to the outside and brazed to follow the thermal expansion of the base plate 10 at this time.

FIG. 5 shows a schematic view of a method of brazing the base plate 10 and the frame body 12. FIG. 5A shows a state in which a brazing material 15 formed in a frame shape is disposed between the base plate 10 and the brazing surface of the frame body 12, and FIG. 5B shows a load acting on the frame body 12. Shows the state of brazing. FIG. 5B shows a state in which the brazing material 15 has not reached the melting temperature. In the state in which the brazing material 15 is not melted, the entire brazed surface of the frame 12 including the ceramic terminals 14 is the base. The plate 10 is pressed. Therefore, when heated to the brazing temperature in this state, the frame 12 and the base plate 10 gradually expand, and for example, the base plate 10 has a larger thermal expansion coefficient than the frame 12. In some cases, it is conceivable that the ceramic terminal 14 will be displaced following the thermal expansion of the base plate 10.
In the case of using silver brazing as the brazing material 15, the temperature is raised to the brazing temperature (about 800 ° C.) in a heating furnace over about 30 minutes. At the same time, the ceramic terminal 14 is displaced.

  Depending on the semiconductor package product, high accuracy is required for the brazing position of the ceramic terminal 14 (the interval between the ceramic terminals 14 opposed to the opposing (facing) wall surfaces of the frame). It becomes defective when 14 is slightly displaced from the normal arrangement position. Further, when the displacement of the ceramic terminal 14 is caused by the effect that the base plate 10 is thermally expanded during brazing and the ceramic terminal 14 is displaced following the thermal expansion, the brazing position of the ceramic terminal varies. Therefore, there is also a problem that the finished dimensional accuracy of the product varies.

  Accordingly, the present invention has been made to solve these problems, and in manufacturing a semiconductor package in which a frame body having a ceramic terminal mounted thereon is brazed to a base plate made of metal, the ceramic terminal is positioned. It is an object of the present invention to provide a method for manufacturing a semiconductor package, which can be brazed without being displaced, and by which a product with high finished dimensional accuracy can be manufactured with high yield.

The present invention has the following configuration in order to achieve the above object.
That is, a brazing material is disposed between a brazing surface of a frame body and a brazing surface of a ceramic terminal attached to a notch formed in the frame body, and a base plate to which these brazing surfaces are joined, and the base plate In a method for manufacturing a semiconductor package, in which a heat is applied to a direction in which a frame is clamped, the brazing material is heated to a melting temperature, and the base plate, the frame, and a ceramic terminal are brazed. A brazing material is disposed on the brazing surface at a position that does not overlap with the mounting position of the ceramic terminal attached to the frame, and is brazed.
In addition, a brazing material formed in the shape of a strip having the same width as the frame is used as the brazing material that is disposed at a position that does not overlap with the mounting position of the ceramic terminal.

Further, a brazing material is disposed between the brazing surface of the frame body and the brazing surface of the ceramic terminal attached to the notch formed in the frame body, and the base plate to which these brazing surfaces are joined, and the base plate In a method for manufacturing a semiconductor package, in which a heat is applied to a direction in which a frame is clamped, the brazing material is heated to a melting temperature, and the base plate, the frame, and a ceramic terminal are brazed. Brazing the brazing material at a position that does not overlap with the mounting position of the ceramic terminal attached to the frame, and the base plate and the ceramic terminal at the brazing surface. Features.
Further, the workability of manufacturing the semiconductor package is improved by temporarily attaching the ceramic terminal to the cutout of the frame body, and aligning and brazing the frame body on which the ceramic terminal is temporarily attached and the base plate. be able to.

  According to the method for manufacturing a semiconductor package of the present invention, when the frame is brazed to the base plate, the brazing material functions as a spacer that acts to separate the base plate and the frame, thereby providing the base plate. In addition, when the frame body is heated and thermally expanded, it is possible to prevent the ceramic terminal from being displaced following the base plate and the like, thereby obtaining a semiconductor package product with high finished dimensional accuracy.

(First embodiment)
In the method of manufacturing a semiconductor package according to the present invention, a metal frame 12 is brazed to a metal base plate 10 formed in a flat plate shape, and the frame 12 is similar to the ceramic shown in FIG. A semiconductor package to which the terminals 14 are attached is obtained. The basic manufacturing method is the same as the conventional semiconductor package manufacturing method, and the feature of the present invention is that the frame body 12 is brazed to the base plate 10. It is in the point which devised the shape and arrangement of the brazing material to be used.

FIG. 1 shows a first embodiment of a semiconductor package manufacturing method in which a base plate 10 and a ceramic terminal 14 are mounted using two brazing members 16a and 16b formed in a strip shape. A method of manufacturing a semiconductor package by brazing the frame 12 is shown.
In this embodiment, a clad material having a three-layer structure of copper-molybdenum-copper is used as the base plate 10 and the frame 12 is made of an iron-nickel-cobalt alloy. The material of the frame 12 is not limited.

In the present embodiment, two notches 12a for mounting the ceramic terminals 14 are provided on each of the opposing long sides of the frame 12 so as to face each other, and the ceramic terminals 14 are brazed with the notches 12a. The frame body 12 that is temporarily attached using is brazed to the base plate 10.
The ceramic terminal 14 is made of alumina ceramic, and is pre-metallized at a portion in contact with the frame 12 and electrically connects a semiconductor element mounted on the semiconductor package and a lead terminal outside the semiconductor package. A wiring pattern 14a for connection is formed. In addition, the ceramic terminal 14 may not be temporarily attached to the frame 12 but the ceramic terminal 14 may be assembled when each component is set on a jig.

  As shown in FIG. 1, brazing materials 16 a and 16 b such as silver brazing used in the present embodiment are formed to have substantially the same length as the frame portions 12 b and 12 c where the ceramic terminal 14 is not attached in the frame body 12. This is a preform (preform) formed into a strip shape having substantially the same width as the brazed surface of the frame body 12. The brazing members 16a and 16b are arranged on the base plate 10 in accordance with the positions where the frame portions 12b and 12c of the frame 12 are joined, and the frame 12 is aligned with the base plate 10 and brazed.

FIG. 2 is an explanatory diagram of a method for brazing the base plate 10 and the frame body 12 using the brazing materials 16a and 16b described above.
Fig.2 (a) shows arrangement | positioning of the base board 10, the frame 12, and the brazing | wax material 16a, 16b at the time of brazing. FIG. 2 shows the front surface of the frame 12 on which the ceramic terminals 14 are mounted. In FIG. 2A, the brazing materials 16a and 16b are mounted on the ceramic terminals 14 on the frame 12. It indicates that the frame portions 12b and 12c are not aligned and are arranged.

FIG. 2B shows a state in which a load is applied to the frame body 12 to press the frame body 12 against the base plate 10 and braze. Actually, the base plate 10 and the frame body 12 are assembled to a jig, and the pressure is applied to the base plate 10 and the frame body 12 to press the base plate 10 and the frame body 12 so that the load is applied. Can be added.
A characteristic action in the brazing method of the present embodiment is that when the base plate 10 and the frame body 12 are supported by a jig and the temperature is raised to the brazing temperature in a heating furnace, the brazing materials 16a and 16b are used. 2 (b), the brazing materials 16a and 16b act so as to separate the brazing surface of the frame body 12 (ceramic terminal 14) and the joining surface of the base plate 10 in a temperature range where the metal does not melt. To function as a spacer.

  That is, when the temperature of the heating furnace is increased to the brazing temperature, the base plate 10 and the frame body 12 both thermally expand as the temperature rises. For example, the base plate 10 expands more than the frame body 12. Even when the coefficient is large, the brazing materials 16a and 16b act as spacers, so that the brazing surface of the ceramic terminal 14 and the base plate 10 are not in contact with each other, or even if they are in contact, the ceramic according to the thermal expansion of the base plate 10 It is possible to maintain a state in which a pressing force that causes the terminal 14 to follow and deviate is not applied, and to suppress the action of the ceramic terminal 14 to be displaced following the thermal expansion of the base plate 10. .

FIG. 2C shows a state in which the brazing members 16 a and 16 b are melted in the heating furnace, and the frame body 12 is brazed to the base plate 10. When the brazing materials 16a and 16b are melted, the molten brazing material 16 extends from the brazing surface of the frame portions 12b and 12c, which are the short sides of the frame body 12, to the long side, along the brazing surface of the frame body 12. The frame body 12 is brazed to the base plate 10 over the entire circumference of the frame body 12. At this time, the brazing material 16 also wraps around the brazed surface of the ceramic terminal 14 (the surface on which metallization is applied).
By brazing the frame body 12 by applying a load, it is possible to braze without causing a hole or a gap defect in the brazed portion. The base plate 10, the frame body 12, and the ceramic terminal 14 are hermetically sealed. It is brazed.

  When the brazing materials 16a and 16b are melted, the tension acting on the frame body 12 due to the thermal expansion of the base plate 10 is between the base plate 10 even at the portion where the ceramic terminals 14 are mounted. Although acting directly, the ceramic terminal 14 does not follow the thermal expansion of the base plate 10 and is brazed to the base plate 10 at a position supported by the frame 12. It is possible to braze the ceramic terminal 14 with a predetermined dimensional accuracy without shifting the brazing position.

(Second Embodiment)
FIG. 3 shows a second embodiment of a semiconductor package manufacturing method according to the present invention.
In the present embodiment, as the frame body 12 to be brazed to the base plate 10, the brazing surface of the short side frame portions 12 b and 12 c where the ceramic terminal 14 is not mounted on the frame body 12 over the entire length of the brazing surface. The brazing material 16c is fused, and the frame body 12 to which the brazing material 16c is fused and the base plate 10 are aligned and brazed.

3A shows a state in which the frame body 12 and the base plate 10 to which the brazing material 16c has been fused are viewed from the front, and FIG. 3B shows a state in which the frame body 12 to which the brazing material 16c has been fused and The state which applied the load to the base board 10 and brazed is shown explanatoryally.
Also in this embodiment, the brazing material 16c fused to the frame portions 12b and 12c functions as a spacer that acts to separate the base plate 10 and the frame 12, and the base plate 10 is thermally expanded during brazing. In doing so, the frame 12 and the base plate 10 can be brazed by following the base plate 10 and preventing the ceramic terminals 14 from being displaced.

  FIG. 3B shows a state in which a load is applied and brazed in the direction in which the base plate 10 and the frame 12 are sandwiched in the heating furnace. Since the brazing material 16c acts as a spacer, the brazed surface of the ceramic terminal 14 and the base plate 10 are separated from each other, or the pressing force with which the ceramic terminal 14 is pressed against the base plate 10 is suppressed. It is possible to prevent the ceramic terminal 14 from being displaced following the thermal expansion of the base plate 10 when the base 10 is heated and thermally expanded.

  Thus, in order for the brazing material 16 to function effectively as a spacer, it is necessary to form the brazing material 16c at a protruding height of a certain level or more. The protrusion height required for the brazing material 16c depends on the size of the frame body 12, the load applied to the frame body 12, the material of the frame body 12, and the like, but in this embodiment, the height of the brazing material 16c is 0. The positional deviation of the ceramic terminal 14 could be effectively suppressed by setting the thickness to 0.04 to 0.06 mm. The frame used in the present embodiment is a 15 × 15 mm rectangular frame made of iron-nickel-cobalt alloy, and the base plate is a clad material made of a copper-molybdenum-copper three-layer structure.

  Also when using the brazing material 16a, 16b formed in a strip shape used in the first embodiment, a material having a thickness of 0.04 to 0.06 mm is used, as in the brazing material 16c in the present embodiment. By doing so, it is possible to prevent the ceramic terminal from being displaced following the elongation due to the thermal expansion of the base plate 10 during brazing, and to obtain a suitable spacer action.

  According to the semiconductor package manufacturing method of the present embodiment, the brazing material 16c is fused in advance to the frame 12, so that the brazing materials 16a and 16b are separated from the frame 12 as in the first embodiment. Compared to the method used, the parts can be easily set on the jig, and the workability in manufacturing the semiconductor package can be improved.

(Test results)
Table 1 shows the results of testing the finishing accuracy of actual products in order to examine the operational effects of the semiconductor package manufacturing method according to the above-described embodiment. In Table 1, (1) is a method according to the first embodiment, (2) is a method according to the second embodiment, and (3) is a preform formed in the shape of a frame having the same shape as the frame as a brazing material. 6 shows a result of manufacturing the semiconductor package shown in FIG. 6 by brazing the frame body to the base plate and measuring the distance between the ceramic terminals attached facing the frame body. The values shown in Table 1 indicate the amount of deviation from the reference value. The frame used in the test is a 15 × 15 mm rectangular frame made of iron-nickel-cobalt alloy, and the base plate is a copper-molybdenum-copper three-layer clad material, 20 × 20 mm, thickness. 1 mm. In (1) and (2), a brazing material having a width of 0.5 mm × a length of 12 mm × a thickness of 0.04 mm is used as the brazing material. In (3), the brazing material has substantially the same shape as the frame. A silver solder having a thickness of 0.02 mm was used.

  The test results in Table 1 are based on the case of the methods of the first embodiment and the second embodiment, compared to the method of manufacturing a semiconductor package using a conventional brazing material (preform) formed in a frame shape. Indicates that the amount of displacement of the ceramic terminal from the reference position is greatly suppressed. This test result shows that the brazing method of the above-described embodiment, that is, the method of brazing the frame body 12 and the base plate 10 using the spacer action of the brazing material is extremely effective in preventing the displacement of the ceramic terminal 14. It is shown that.

Thus, when brazing the frame body 12 to which the ceramic terminals are attached to the base plate 10, the brazing material is also used as a spacer for inserting between the frame body 12 and the base plate 10. The arrangement of the brazing material in the case is not limited to the example of the embodiment described above, and can be appropriately arranged.
FIG. 4 shows another arrangement example of the brazing material 16. The frame 12 shown in FIG. 4 (a) has ceramic terminals 14 mounted on opposing frame portions, brazing material 16 is disposed so as to pass through the corner portions of the frame 12, and a short side intermediate portion. In this example, the brazing material 16 is arranged. FIG. 4B shows an example in which the ceramic terminals 14 are arranged on each of the long side and the short side of the frame 12. The brazing material 16 is arranged so as to pass through the corner portion of the frame 12 and arranged on the long side. This is an example in which a brazing material 16 is disposed between two ceramic terminals 14.

  As described above, when the brazing material 16 is arranged, the brazing material 16 is arranged in an arrangement that does not overlap with the arrangement position of the ceramic terminal 14 on the brazing surface of the frame body 12, and thus the same effect as that of the above-described embodiment. Thus, it is possible to perform brazing while preventing the displacement of the ceramic terminal 14 during brazing. Instead of arranging the brazing material 16 as shown in FIG. 4, the brazing material 16 is fused in advance to the brazing surface of the frame 12 in accordance with the arrangement position of the brazing material 16. The fused frame 12 and the base plate 10 may be aligned and brazed.

It is explanatory drawing which shows the method of arrange | positioning brazing material to a base board and brazing a frame. It is explanatory drawing which shows the manufacturing process of 1st Embodiment of the manufacturing method of a semiconductor package. It is explanatory drawing which shows the manufacturing process of 2nd Embodiment of the manufacturing method of a semiconductor package. It is explanatory drawing which shows the other arrangement | positioning method of the brazing material in brazing. It is explanatory drawing which shows the manufacturing method of the conventional semiconductor package. It is a perspective view which shows the structure of a semiconductor package.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Base board 12 Frame 12a Notch 12b, 12c Frame part 14 Ceramic terminal 15, 16, 16a, 16b Brazing material

Claims (4)

A brazing material is disposed between the brazing surface of the frame body and the brazing surface of the ceramic terminal attached to the notch formed in the frame body, and the base plate to which these brazing surfaces are joined;
In the method of manufacturing a semiconductor package, heating to a temperature at which the brazing material is melted while applying a load in a direction in which the base plate and the frame are sandwiched, and brazing the base plate, the frame, and the ceramic terminal.
A method of manufacturing a semiconductor package, comprising: brazing a brazing material on a brazing surface of the frame so as not to overlap a mounting position of a ceramic terminal attached to the frame.   2. The method of manufacturing a semiconductor package according to claim 1, wherein a brazing material formed in a strip shape having the same width as that of the frame body is used as the brazing material arranged at a position not overlapping with the mounting position of the ceramic terminal. . A brazing material is disposed between the brazing surface of the frame body and the brazing surface of the ceramic terminal attached to the notch formed in the frame body, and the base plate to which these brazing surfaces are joined;
In the method of manufacturing a semiconductor package, heating to a temperature at which the brazing material is melted while applying a load in a direction in which the base plate and the frame are sandwiched, and brazing the base plate, the frame, and the ceramic terminal.
At the brazing surface of the frame body, the frame body in which a brazing material is fused at a position not overlapping with the mounting position of the ceramic terminal attached to the frame body, the base plate, and the ceramic terminal are aligned. A method for manufacturing a semiconductor package, comprising: attaching a semiconductor package.   The ceramic terminal is temporarily attached to the cutout of the frame body, and the frame body on which the ceramic terminal is temporarily attached and the base plate are aligned and brazed. The manufacturing method of the semiconductor package of description.

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