JP5154836B2 - Electronic chip mounting base, manufacturing method thereof, and electronic apparatus - Google Patents

Description

  The present invention relates to an electronic chip mounting base, a manufacturing method thereof, and an electronic device, and more particularly to a structure of a lead insertion hole in the base.

An electronic chip such as a light emitting diode is used in a state of being mounted on an electronic chip mounting base including a stem, a lead, and the like (see, for example, Patent Document 1).
As shown in FIG. 7, the electronic chip mounting base has a stem 931 and leads 932 made of a copper (Cu) alloy or the like as its constituent elements. The lead 932 is inserted into a through hole 9311 formed in the stem 931, and is fixed with a filling layer 933 made of glass or the like interposed therebetween. In the electronic chip mounting base proposed in Patent Document 1, a plurality of projections and depressions are provided on the inner wall of the through-hole 9311 to increase the bonding area between the filling layer 933 and the stem 931, thereby bonding between each other. The strength is improved.
JP-A-56-112773

  However, in the base proposed in Patent Document 1, it is conceivable that bubbles remain in the through-hole 9311 between the filling layer 933 and the stem 931, particularly in the portion indicated by the arrow D shown in FIG. That is, the filling layer 933 is formed by inserting cylindrical glass between the inner wall surrounding the through-hole 9311 and the outer periphery of the lead 932, and applying heat to the melt to form the filling layer 933. Although a plurality of irregularities are formed on the inner wall surrounding the hole 9311, there arises a problem that bubbles remain.

Thus, when bubbles remain between the stem 931 and the filling layer 933, problems such as a decrease in strength and a decrease in hermeticity occur.
The present invention has been made to solve such problems, and an electronic chip mounting base capable of ensuring high bonding strength and high airtightness at a lead insertion point, a manufacturing method thereof, and an electronic device The purpose is to provide.

In order to achieve the above object, the present invention adopts the following configuration.
An electronic chip mounting base according to the present invention has an electronic chip mounting area on one main surface, a stem provided with a through hole in the vicinity of the mounting area, a lead inserted through the through hole, a lead An electronic chip mounting base having a filling layer filled and arranged in a through hole in a state where the through hole is inserted, and the through hole has the smallest cross-sectional area at one central portion in the thickness direction of the stem, The neck portion, which has a shape that gradually increases from the portion toward both main surfaces of the stem and has the narrowest hole cross section, is formed to have a length in the thickness direction of the stem, and the length of the neck portion in the thickness direction of the stem Is 20% or less with respect to the thickness of the stem.

In addition, the electronic chip mounting base manufacturing method according to the present invention executes the steps (S1) to (S4).
(S1) A step of preparing a stem having an electronic chip mounting area on one main surface and provided with a through hole in the vicinity of the mounting area.
(S2) A step of inserting the lead into the through hole provided in the stem.

(S3) A step of inserting an insulating material between the inner wall of the through hole of the stem and the outer surface of the lead.
(S4) A step of adding heat of fusion to the interposed insulating material.
In the manufacturing method according to the present invention, in the stem prepared in the step (S1), the cross-sectional area of the through-hole is the smallest at one place in the central portion in the thickness direction of the stem, and from that place to both main surfaces of the stem. It is provided in the shape which becomes gradually large toward it.

As described above, in the electronic chip mounting base according to the present invention, the through hole provided in the stem is not a hole having a uniform cross-sectional shape, but has an unevenness on the inner wall thereof. Compared with a certain case, an anchor effect can be obtained and a high bonding strength can be obtained.
Further, in the electronic chip mounting base according to the present invention, the portion having the smallest cross-sectional area in the through hole is one portion in the thickness direction of the stem, and gradually increases from the portion toward the two main surfaces. Therefore, the remaining of bubbles in the through-hole is suppressed as compared with the base proposed in Patent Document 1. In other words, the electronic chip mounting base according to the present invention adopts a shape in which bubbles do not easily remain in the through holes in the filling layer forming step.

As described above, in the electronic chip mounting base according to the present invention, high joint strength and high airtightness can be secured at the lead insertion locations. Since the electronic device according to the present invention includes the electronic chip mounting base according to the present invention, the same effects as described above can be obtained.
In the method for manufacturing an electronic chip mounting base according to the present invention, the shape of the through hole in the stem is the same as that of the electronic chip mounting base according to the present invention in the execution of the steps (S1) to (S4). Since it is configured, in the electronic chip mounting base after manufacture, it is possible to ensure high bonding strength and high airtightness at the lead insertion location.

Hereinafter, the best mode for carrying out the present invention will be described using an example. The embodiment adopted in the following description is an example used to explain the configuration, operation, and effect of the present invention in an easy-to-understand manner, and limits the present invention in any way other than the essential technical features. is not.
(Embodiment)
1. Configuration of Electronic Device 1 The configuration of the electronic device 1 according to the present embodiment will be described with reference to FIG.

As shown in FIG. 1, in the electronic device 1 according to the present embodiment, the electronic chip 10 is mounted on one main surface of the mounting base 30 via the submount substrate 20.
The mounting base 30 includes a plate-like stem 31 and two leads 32a and 32b that pass through through holes provided in the stem 31 as main elements. The terminals of the electronic chip 10 are joined to the leads 32a and 32b on the mounting base 30 via bonding wires 40a and 40b.

2. Configuration of Mounting Base 30 The configuration of the mounting base 30 having the most characteristics among the configurations of the electronic apparatus 1 will be described with reference to FIGS. 2 and 3.
As shown in FIG. 2, in the mounting base 30 according to the present embodiment, two leads 32 a and 32 b are inserted through a through hole provided in the stem 31, and filling layers 33 a and 33 b are formed therebetween. It has a configuration. Among these, the stem 31 is made of copper (Cu) or a Cu alloy, or a clad material containing Cu or a Cu alloy.

The leads 32a and 32b are made of Kovar or FeNi, and the filling layers 33a and 33b are made of soda glass or borosilicate glass.
As shown in FIG. 3, the through hole 311 in the stem 31 is not provided with a uniform cross-sectional area in the thickness direction (Z-axis direction) of the stem 31, but at the central portion in the Z-axis direction. It has a portion with the smallest cross-sectional area (the portion is described as “A ₁ portion”), and the cross-sectional area from the portion A ₁ toward both sides in the Z-axis direction (to both main surface sides of the stem 31). The shape gradually increases. Hereinafter, portions where the cross-sectional area gradually increases are referred to as “A ₂ portion” and “A ₃ portion”.

In the A ₂ portion and the A ₃ portion, the inner wall surface 311f is tapered so as to have an angle θ with respect to a virtual straight line along the Z axis. Here, the angle θ is in the range of 0.5 [°] to 7 [°], and preferably in the range of 1 [°] to 5 [°]. In FIG. 1 to FIG. 3, the angles are exaggerated for easy understanding of the state in which the cross-sectional areas of the A ₂ part and the A ₃ part gradually increase.

In mounting base 30 according to the present embodiment, the through hole 311 of the stem 31, A ₁ moiety is formed has a length t1 in Z-axis direction. About length t1, it is set up to follow a following formula, for example.
[Formula 1]
t1 / (t1 + t2 + t3) = 10 [%]
3. Manufacturing Method of Mounting Base 30 Hereinafter, fixing of leads 32a and 32b to the through hole 311 of the stem 31 in the manufacturing method of the mounting base 30 will be described with reference to FIG. In FIG. 4, only one lead 32a and the through hole 311 through which the lead 32a is inserted are shown.

As shown in FIG. 4A, a stem 31 having a through hole 311 having the above configuration is prepared. The method for forming the through hole 311 in the stem 31 corresponds to the A ₂ portion (see FIG. 3), for example, by punching a hole from one main surface of the stem 31 by punching and at that time or thereafter. Taper the part. Then, applying also tapered at positions corresponding to A ₃ portion also by press from the main surface of the opposite side. In this way, the stem 31 having the through hole 311 can be prepared.

The lead 32a is inserted into the through hole 311 of the stem 31, and the glass cylinder 330a made of the constituent material of the filling layer 33a is covered.
As shown in FIG.4 (b), the heat | fever which fuses this is added with respect to the glass cylinder 330a. In addition, although illustration is abbreviate | omitted, when adding heat, each material is covered with a jig and a position control is performed.

The glass cylinder 330a that has received heat tends to have a spherical outer peripheral surface. The glass cylinder 330a is deformed into a shape as shown in FIG. 4B (melting intermediate 331a), and first comes into contact with the A ₁ portion having the smallest cross-sectional area in the through hole 311.
As shown in FIG. 4C, the molten intermediate 331a further flows to fill the space between the inner wall surrounding the through hole 311 and the lead 32a, and the filled layer 33a is formed.

As described above, the leads 32a and 32b in the mounting base 30 can be fixed.
4). Advantages Advantages of the mounting base 30 adopting the above-described configuration and the electronic apparatus 1 including the same will be described.
As shown in FIG. 3, in the mounting base 30 according to the present embodiment, the cross-sectional shape of the through hole 311 provided in the stem 31 is not a straight hole, but the cross-sectional area is the smallest in the A ₁ portion, and the A ₂ portion In addition, since the taper shape that extends toward the main surface side of the stem 31 at the A ₃ portion, the anchor effect by the A ₁ portion can be obtained as compared with the straight hole. In addition, since the joint area between the stem 31 and the filling layers 33a and 33b can be increased, a high joint strength between the stem 31 and the leads 32a and 32b can be obtained.

Further, the mounting base 30 according to this embodiment, the through hole 311 of the stem 31, and a state of a reduced diameter only A ₁ moiety, as the mounting base according to Patent Document 1 shown in FIG. 7 Since a plurality of irregularities are not provided, it is possible to suppress residual bubbles between the stem 31 and the filling layers 33a and 33b in the through hole 311. For this reason, in the mounting base 30 according to the present embodiment, reliable fixing between the stem 31 and the leads 32a and 32b and reliable airtightness can be ensured.

  Furthermore, since the mounting base 30 according to the present embodiment employs the through hole 311 having the above-described structure, there is no need for complicated work when the through hole 311 is provided, that is, like the mounting base according to Patent Document 1. However, in this embodiment, the through-hole 311 is provided only by the simple press work as described above. Can do.

In addition, it is desirable that the taper angles of the A ₂ part and the A ₃ part in the through hole 311 are in the above numerical range, so that an anchor effect can be obtained and stress is concentrated on the boundary part with the A ₁ part. This is derived from two factors that can be relaxed.
In the present embodiment, the material of the stem 31 is copper (Cu) or a Cu alloy, or a clad material containing Cu or a Cu alloy, which is more thermally conductive than Fe or its alloy material. This is because it is desirable from the viewpoint of cooling the electronic chip 10.
(Modification 1)
A mounting base according to Modification 1 will be described with reference to FIG. Since the mounting base according to this modification has no difference from the above embodiment except for the shape of the through hole 511 of the stem 51, only the shape of the through hole 511 will be described.

As shown in FIG. 5, the through hole 511 in the stem 51 has a B ₁ portion having the smallest cross-sectional area at the center in the thickness direction of the stem 51. The form of this part is the same as that of the through hole 311. In this modification, the inner wall surface 511f of the B ₂ moiety and B ₃ moiety is not a straight line in cross section, has a curve. However, there is no portion that is smaller in diameter than the B ₁ portion.

The mounting base according to this modification that employs the stem 51 having the through hole 511 having such a shape also has the same advantage as the mounting base 30 according to the above-described embodiment.
(Modification 2)
A mounting base according to Modification 2 will be described with reference to FIG. Since the mounting base according to this modification is not different from the above embodiment and modification 1 except for the shape of the through hole 611 of the stem 61, only the shape of the through hole 611 will be described.

As shown in FIG. 6, in the through hole of the stem 61 according to this modification, the portion with the smallest cross-sectional area does not have a length in the thickness direction of the stem 61, and the tapered C ₂ portion and C ₃ portion It consists only of. As described above, the same effect is achieved also in the present modified example having the configuration in which the A ₁ part of the through hole 311 according to the above embodiment or the B ₁ part of the through hole 511 according to the modified example 1 is not provided. It is possible. In addition, since the portion having a uniform cross-sectional area is not formed in this way, the work related to the formation of the through hole 611 can be simplified.
(Other matters)
It is also possible to employ a combination of the first modification and the second modification, and various variations of the parts corresponding to the A ₂ part and the A ₃ part.

Further, the present invention is not limited to the numerical values, materials, and the like shown as examples in the above-described embodiment and the like, and the same effects as described above can be obtained if the configuration has essential characteristics.
In the first embodiment, the length t1 of the A ₁ portion in the thickness direction of the stem 31 is the numerical value shown in the above (Equation 1), but the same as the above if the range is 20 [%] or less. The effect of can be obtained.

  The present invention is a technique effective for realizing an electronic device that requires bonding strength and airtightness of leads.

It is sectional drawing which shows the structure of the electronic device 1 which concerns on embodiment. FIG. 3 is a cross-sectional view showing the configuration of the mounting base 30 in the configuration of the electronic device 1. 5 is a cross-sectional view showing the shape of a through hole 311 in the stem 31 of the mounting base 30. FIG. FIG. 10 is a process diagram showing a process related to fixing of the lead 32 a to the through hole 311 in the manufacturing process of the mounting base 30. FIG. 10 is a cross-sectional view showing the shape of a through hole 511 opened in a stem 51 in the configuration of a mounting base according to Modification 1; FIG. 10 is a cross-sectional view showing the shape of a through hole 611 opened in a stem 61 in the configuration of a mounting base according to Modification 2. It is sectional drawing which shows the shape of the through-hole 9311 opened by the stem 931 among the structures of the mounting base which concerns on a prior art example.

Explanation of symbols

1. Electronic device 10. Electronic chip 20. Submount substrate 30. Mounting base 31, 51, 61. Stem 32a, 32b. Lead 33a, 33b. Packed bed 40a, 40b. Bonding wires 311, 511, 611. Through hole

Claims (5)

A stem having an electronic chip mounting area on one main surface, and a through hole provided in the vicinity of the mounting area;
A lead inserted through the through hole;
An electronic chip mounting base having a filling layer filled and disposed in the through hole in a state where the lead is inserted;
The through-hole has a cross-sectional area that is the smallest at one place in the central portion in the thickness direction of the stem, and has a shape that gradually increases from the place toward both main surfaces of the stem ,
The neck portion having the narrowest hole cross-section is formed having a length in the thickness direction of the stem,
The length of the neck part in the thickness direction of the stem is 20% or less with respect to the thickness of the stem . In the gradually enlarged portion of the through hole, the inner wall is formed in a tapered shape with an angle of 0.5 ° or more and 7 ° or less with respect to a virtual straight line orthogonal to the one main surface of the stem. The electronic chip mounting base according to claim 1, wherein the electronic chip mounting base is provided. In the gradually expanding portion, an inner wall is formed in a tapered shape at an angle of 1 ° or more and 5 ° or less with respect to a virtual straight line orthogonal to the one main surface of the stem. Item 9. The electronic chip mounting base according to Item 1. The base for mounting an electronic chip according to any one of claims 1 to 3 , wherein the stem is a plate made of a copper alloy or a clad material containing a copper alloy. An electronic device having an electronic chip mounted on a base,
5. An electronic device according to claim 1, wherein the base for mounting an electronic chip according to any one of claims 1 to 4 is used as the base.

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