CN113922205A

CN113922205A - Substrate, method for forming packaging structure by using substrate and packaging structure

Info

Publication number: CN113922205A
Application number: CN202111089042.3A
Authority: CN
Inventors: 段银祥; 周萌; 徐虎; 田梓峰; 张世忠; 许颜正
Original assignee: YLX Inc
Current assignee: YLX Inc
Priority date: 2018-01-05
Filing date: 2018-01-05
Publication date: 2022-01-11
Anticipated expiration: 2038-01-05
Also published as: WO2019134268A1; CN113922205B; CN110010557B; CN110010557A

Abstract

The invention relates to a substrate, a method for forming a packaging structure by using the substrate and the packaging structure. The substrate body has a bonding surface for bonding the members to be bonded with a bonding material. The first groove structure is formed in the engaging face and has an opening size equal to a size of the engaged member to enable positioning of the engaged member in a planar direction of the engaging face. The second groove structure is formed in the first groove structure and has a second depth such that the first groove structure has a first depth smaller than the second depth only at a plurality of support positions along the periphery capable of supporting the engaged member in the vertical direction. A heat conducting stage for conducting heat from the engaged components is provided inside the second groove structure, with a top surface at most flush with the bottom of the first groove structure. According to the invention, the thickness uniformity of the bonding material and the positioning of the bonded parts can be strictly controlled in the device packaging process.

Description

Substrate, method for forming packaging structure by using substrate and packaging structure

Technical Field

The present invention relates to a substrate, a substrate packaging method, and a package structure, and more particularly, to a substrate, a package structure forming method using the substrate, and a package structure, which are capable of strictly controlling the thickness uniformity of a bonding material and the positioning of a bonded part in a device packaging process.

Background

The light source adopting the blue Laser Diode (LD) excitation wavelength conversion device has the advantages of high efficiency, high brightness and the like. However, since the blue LD has a small spot and a large power and thus has a large optical power density, the heat dissipation performance of the wavelength conversion device is required to be high. Conventional wavelength conversion devices, for example, having a "thermally conductive substrate + diffuse reflective layer + light emitting layer" structure, cannot meet their heat dissipation requirements. Compared with the structure of the heat-conducting substrate, the diffuse reflection layer and the light-emitting layer, the structure is more beneficial to heat dissipation.

At present, the structure of the heat conduction substrate, the diffuse reflection layer and the light emitting layer mainly adopts solder to weld metallized light emitting ceramic or glass and a copper substrate. Fig. 1 shows such a wavelength conversion device package structure. As shown in fig. 1, the package structure includes a copper substrate 1, a solder paste 2, a wavelength conversion chip 3 composed of a wavelength conversion material 32 and a metallization layer 31, and a lens group 4. In this structure, excitation light having a wavelength λ 1 is incident on the wavelength conversion material 32 through the lens group 4, so that the wavelength conversion material 32 emits excited light having a wavelength λ 1 different from the wavelength λ 1.

The solder paste 2 is a bonding layer for connecting the wavelength conversion chip 3 as a bonded component to the copper substrate 1. The thickness of the solder paste 2 becomes uneven due to the influence of the viscosity of the solder material, wettability, soldering process and other conditions. Meanwhile, the fluidity and uncontrollable property of the liquid tin may cause the position of the wavelength conversion chip to drift and/or tilt during the reflow soldering process. The deviated chip will affect the light receiving efficiency of the lens assembly 4 and the assembly of the whole light source system.

To solve the misalignment of the members to be joined and the thickness uniformity of the joining layer, the following techniques have been proposed.

For example, patent document CN104517931B proposes a substrate having a protruding support array provided on the surface thereof. The thickness uniformity of the solder layer between the backing plate and the substrate is controlled by the array of support points on the substrate. Further, the array of support points is located on the back of the backing plate and/or around or at the four corners of the surface of the base plate. The design ensures that the fulcrum array can not block the flow of the welding layer on the premise of supporting, thereby reducing the probability of occurrence of cavities and discontinuous welding spots in the welding layer to the maximum extent. However, the use of the copper substrate does not solve the problem of the offset of the liner plate. Moreover, to solve the problem of lining plate deviation, correction needs to be performed through a positioning jig, which increases the complexity and cost of the process.

Patent document CN105814681A proposes a substrate having a groove structure. In the substrate, the opening of the recess is larger than the member to be joined, and the outer peripheral portion of the recess, which the outer peripheral edge of the member to be joined faces, is deeper than the central portion of the recess. The invention mainly aims to solve the problems that the position of a chip is deviated in the welding process of a high-power semiconductor to influence the yield deterioration when a subsequent metal wire is bound and the like. The substrate can improve the positional deviation of the chip in the planar direction, but the substrate cannot control the position of the chip in the vertical direction due to the uncontrollable property of the solder in the vertical direction.

In summary, there are some problems in soldering the wavelength conversion chip on the common copper substrate by using tin-based alloy eutectic soldering or the like. Specifically, in the process of welding, due to the uncontrollable property of the tin alloy in the liquid state, the thickness of the welded layer is inconsistent after welding, so that the wavelength conversion chip is inclined and deviated, and the consistency of the welded sample is poor.

Disclosure of Invention

In view of the shortcomings of the prior art, the present invention aims to prevent the deviation of the bonded components and control the uniformity of the thickness of the bonding material, so that the bonded components after being welded are parallel to the substrate and the lens, thereby ensuring the maximum light-receiving efficiency. In addition, the invention also aims to control the thickness of the bonding material of different samples to have consistency, thereby reducing the debugging work of different samples at the later stage.

According to a first aspect of the present invention, there is provided a substrate comprising: a substrate body having a bonding surface to which a member to be bonded is bonded with a bonding material; a first groove structure formed in the engaging surface and having an opening size equal to a size of the engaged member to enable positioning of the engaged member in a planar direction of the engaging surface; and a second groove structure for accommodating the joining material, the second groove structure being formed in the first groove structure and having a second depth such that the first groove structure has a first depth smaller than the second depth only at a plurality of support positions along a periphery capable of supporting the joined member in a vertical direction; a heat conducting stage for conducting heat from the engaged components is disposed inside the second groove structure, and a top surface of the heat conducting stage is at most flush with a bottom of the first groove structure.

According to a second aspect of the present invention, there is provided a method for forming a package structure using the substrate described above, the method comprising: providing the substrate; printing bonding material to a bonding surface of a bonded member; mounting the part to be joined at the first groove structure of the substrate in such a manner that a joining surface of the part to be joined faces the substrate; placing a weight on the engaged member; placing the combination comprising the base plate, the part to be joined and the weight block obtained at this time in a vacuum eutectic furnace for welding to allow the bonding material to flow freely in the second groove structure of the base plate; and after welding is completed, removing the weight block.

According to a third aspect of the present invention, there is provided a package structure comprising: the above substrate; an engaged member; and a bonding material for bonding the bonded member to the bonding surface of the substrate.

According to the present invention, since the opening size of the first groove structure completely corresponds to the size of the engaged member, the first groove structure can accurately position the position of the engaged member in the substrate in the planar direction.

Further, according to the present invention, since the depth of the first groove structure at the plurality of supporting positions along the periphery is smaller than the depth of the second groove structure, the first groove structure can support the engaged member in the vertical direction.

Thus, according to the first to third aspects of the present invention, the thickness uniformity of the bonding material and the positioning of the bonded components can be strictly controlled in the device packaging process.

The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments are briefly introduced below, the drawings in the following description are only some embodiments of the present invention, and it is obvious for a person skilled in the art to obtain other embodiments and drawings based on the embodiments shown in the drawings without any inventive work.

Fig. 1 shows a package structure of a wavelength conversion device of the related art.

Fig. 2 shows a perspective view of a substrate according to a first example of the present invention.

Fig. 3 shows a plan view of a substrate according to a first example of the present invention.

Fig. 4 shows a cross-sectional view taken along line a-a of fig. 3.

Fig. 5 shows a cross-sectional view taken along line B-B of fig. 3.

Fig. 6 shows a plan view of a package structure according to a first example of the present invention.

Fig. 7 shows a cross-sectional view taken along line C-C of fig. 6.

Fig. 8 shows a cross-sectional view taken along line D-D of fig. 6.

Fig. 9 shows a perspective view of a substrate according to a modified example 1 of the first example.

Fig. 10 shows a perspective view of a substrate according to a modified example 2 of the first example.

Fig. 11 shows a perspective view of a substrate according to a modified example 2 of the first example.

Fig. 12 shows a perspective view of a substrate according to a modified example 3 of the first example.

Fig. 13 shows a perspective view of a substrate according to a second example of the present invention.

Detailed Description

The technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that the drawings are schematic and are not drawn to scale. Relative dimensions and proportions of parts illustrated in the drawings have been shown exaggerated or reduced in size, and any dimensions are exemplary only and not in limitation. Like structures, elements or components in the drawings are referred to by like reference numerals.

First example of substrate

Fig. 2 to 5 show a substrate according to a first example of the present invention. Specifically, fig. 2 shows a perspective view of the substrate of the present invention. Fig. 3 shows a plan view of a substrate of the present invention. Fig. 4 and 5 show cross-sectional views taken along lines a-a and B-B of fig. 3, respectively.

Fig. 6 to 8 show states of a package structure formed using a substrate according to a first example of the present invention. In particular, fig. 6 shows a plan view of a package structure. Fig. 7 and 8 show cross-sectional views taken along lines C-C and D-D of fig. 6, respectively.

The substrate of the invention can be used for packaging various high-power electronic chips, such as wavelength conversion chips and the like. For purposes of illustration only, the wavelength conversion chip is illustrated herein as an example. At this time, solder paste is used as an example of the bonding material.

The substrate 1 of the present invention includes a substrate body 11, a first groove structure 12, and a second groove structure 13.

As shown in fig. 2, for example, the square substrate 1 may be punched or cut from a copper plate raw material, wherein the thickness of the copper plate raw material may be 2mm to 10mm, preferably 3 mm. The planar dimensions of the copper substrate 1 may be 20mm by 20 mm. The material of the substrate 1 can be pure copper or copper alloy with thermal conductivity of more than 300 w/m.k, and copper material with thermal conductivity of 398 w/m.k is preferred. Generally, a nickel plating treatment is performed on a copper substrate in order to prevent molecular diffusion and/or improve corrosion resistance and the like.

The first groove structure 12 and the second groove structure 13 are formed on the bonding surface of the substrate body 11 for bonding the wavelength conversion chip 3 by a process such as laser etching, chemical etching, or machining. In the present example, the wavelength conversion chip 3 may be an electronic chip such as a wavelength conversion chip.

The first groove structure 12 is used to position the wavelength conversion chip 3 in the planar direction and support the wavelength conversion chip 3 in the vertical direction. In the field of electronic chips, the shape of the electronic chip as the wavelength conversion chip 3 is generally square in view of cost and process simplification, but various shapes such as rectangle, triangle, hexagon, and circle are not excluded. In order to achieve positioning and support of the wavelength converting chip 3, the planar shape of the first groove structure 12 (i.e. the shape in fig. 3) should correspond to the shape of the wavelength converting chip. Specifically, the size of the opening of the first groove structure 12 must be equal to the size of the wavelength conversion chip.

For illustrative purposes only, in this example, the planar shape of the first groove structure 12 is a square, as shown in fig. 3. In this case, the wavelength conversion chip 3 should also have a square shape. In fig. 3, the width (side length) of the first groove structure 12 is represented by W0, where W0 should satisfy W0 being the width (side length) of the wavelength conversion chip, whereby the first groove structure 12 can position the wavelength conversion chip in the planar direction. Here, W0 is 5mm, for example.

The second groove structure 13 is a groove structure further formed in the first groove structure 12, and has a depth H2 (see fig. 8). The second groove structure 13 is a space for allowing free flow of solder paste 2 during the reflow soldering process.

In the present example, as shown in fig. 2 and 8, the first groove structure 12 has a depth H1 smaller than the depth H2 only at four corners along the periphery. That is, in the first groove structure 12, the formation position of the second groove structure 13 is other than the four corners. Thus, the first groove structure 12 has four corner support positions along the periphery that can be used to support the wavelength converting chip 3 in the vertical direction.

In addition, in a non-essential but preferred feature, the second groove structure 13 may also extend further outward in four directions from the four sides of the first groove structure 12 to the outside of the first groove structure 12 in order to allow free flow of excess bonding material during the reflow process in case the bonding material 3 exceeds a prescribed amount. In other words, the second groove structure 13 also extends outwardly from the periphery of the first groove structure 12 between the four corner support locations to the exterior of the first groove structure 12.

Thereby, by extending the second groove structure 13 to the outside of the first groove structure 12, the action and effect of allowing the excessive bonding material to flow freely during the reflow soldering process can be further obtained, as compared with the case where the second groove structure 13 does not extend to the outside of the first groove structure 12.

However, it should be understood by those skilled in the art that although the second groove structure 13 is illustrated as having a portion extending to the outside of the first groove structure 12 in all the drawings of the present invention, the second groove structure 13 does not necessarily have to extend outward. The absence of the outwardly extending second groove structure is sufficient to allow free flow of bonding material during the reflow soldering process, provided that the production process can ensure a proper amount of bonding material. In this case, the second groove structure 13 is formed only in the first groove structure 12. At the four sides of the first groove structure 12, the second groove structure 13 is flush with the first groove structure 12. The same applies to the examples described later.

Nevertheless, in the present example, as shown in fig. 2 to 8, the case where the second groove structure 13 extends to the outside of the first groove structure 12 is specifically explained as an example.

Thus, in the case where the second groove structure 13 extends to the outside of the first groove structure 12, the second groove structure 13 is composed of a portion formed in the first groove structure 12 and a portion formed outside the first groove structure 12, and thus has a cross-shaped planar shape.

As shown in fig. 3, the second groove structure 13 has a length W1 and a width W2. Since the second groove structure 13 is formed in the first groove structure 12 at a position other than the four corner support positions, as shown in fig. 5, the width W2 of the second groove structure 13 should be smaller than the width W0 of the first groove structure 12. Moreover, since the second groove structure 13 extends outwardly of the first groove structure 12 from the periphery of the first groove structure 12 between the four corner support locations, the length W1 of the second groove structure 13 should be greater than the width W0 of the first groove structure 12, as shown in fig. 4. Here, for example, the difference between W0 and W2 may be 1mm to 2mm, preferably 1 mm. For example, the difference between W1 and W0 may be 3mm to 15mm, preferably 5 mm.

Fig. 6 to 8 show states of a package structure formed using a substrate according to a first example of the present invention. A process of forming a package structure using the substrate according to the present invention and a package structure formed thereby will be described with reference to fig. 6 to 8.

Before soldering the wavelength converting chip 3 to the substrate 1, the solder paste 2 is printed on the bonding surface (e.g., metalized surface) of the wavelength converting chip 3, for example, using a steel mesh printing method. Then, the wavelength converting chip 3 is mounted at the first groove structure 12 in such a manner that the bonding surface of the wavelength converting chip 3 on which the solder paste is printed faces the substrate 1. Thereafter, a weight is placed on the wavelength conversion chip 3. Then, the assembly including the substrate, the wavelength conversion chip, and the weight member obtained at this time is placed in a vacuum reflow furnace, and soldering is performed according to a set temperature and pressure curve. At this time, the bonding material can flow freely in the second groove structure 13 of the substrate. Finally, after the welding is completed, the weight block is removed. At this time, the package structure shown in fig. 6 is obtained.

Of course, it should be understood that the formation of the package structure and the package structure may also utilize the substrates of other examples described below.

As shown in fig. 6, the depth H1 of the first groove structure 12 is equal to or less than the thickness H0 of the chip 3. Here, for example, the thickness H0 of the chip 3 is 300 μm. For example, the difference between H0 and H1 may be 0 to 100. mu.m, preferably 50 μm.

For example, the depth H2 of the second groove structure 13 is greater than the thickness H0 of the chip 3. As can be seen from FIG. 9, the thickness of the solder paste 2 is H2-H1, which is 100 to 300 μm, preferably 150 μm.

According to the present example, since the opening size of the first groove structure 12 completely corresponds to the size of the chip 3, the first groove structure can accurately position the position of the chip 3 in the substrate 1 in the planar direction. Even during the reflow process, the chip 3 does not drift in the planar direction due to the fluidity and uncontrollable properties of the solder paste 2.

In addition, according to the present example, since the depth H1 of the four corner support positions of the first groove structure 12 is smaller than the depth H2 of the second groove structure 13, the first groove structure 12 can support the chip 3 in the vertical direction, and thus the chip 3 does not suffer from any skew during the reflow soldering process.

Further, according to the present example, since the second groove structure 13 is formed in the first groove structure 12 and has a depth greater than that of the first groove structure 12, the solder paste 2 can freely flow during the reflow process, thereby improving the uniformity of the thickness of the solder paste 2 between the chip 3 and the substrate 1. In addition, alternatively, since the second groove structure 13 may further have a portion extending to the outside of the first groove structure 12, it is possible to freely flow in the second groove structure 13 even if the solder paste 2 exceeds a prescribed amount during the reflow process, thereby improving the uniformity of the thickness of the solder paste 2 between the chip 3 and the substrate 1.

In a first example, the second groove structure extends outwardly from a perimeter of the first groove structure between the plurality of support locations. However, the second groove structure may also extend outwardly from a portion of the perimeter of the first groove structure between the plurality of support locations. This case is explained below by listing modified examples 1 to 3.

< variation example 1 of the first example >

Fig. 9 shows a perspective view of a substrate according to modified example 1.

In the first example, the second groove structures 13 extend outwardly from four sides of the first groove structure 12 to the outside of the first groove structure 12. However, as shown in fig. 9, in the modified example 1, the second groove structure 13 extends outward from three sides of the first groove structure 12 to the outside of the first groove structure 12, but does not extend outward from the remaining one side (in this example, the upper side) of the first groove structure 12.

As can be seen from fig. 9, at the upper side edge, the first groove structure 12 and the second groove structure 13 are flush.

The substrate according to the present modified example can also obtain the same action and effect as the first example.

< variation example 2 of the first example >

Fig. 10 and 11 show perspective views of a substrate according to a modified example 2.

In the first example, the second groove structures 13 extend outwardly from four sides of the first groove structure 12 to the outside of the first groove structure 12. However, as shown in fig. 10 and 11, in modified example 2, the second groove structures 13 extend outwardly from two opposite sides or adjacent sides of the first groove structure 12 to the outside of the first groove structure 12, but do not extend outwardly from the remaining two opposite sides (in this example, the upper side and the lower side of fig. 10) or adjacent sides (in this example, the lower side and the right side of fig. 11) of the first groove structure 12.

As can be seen from fig. 10, at the upper and lower side edges, the first groove structure 12 and the second groove structure 13 are flush. As can be seen from fig. 11, at the lower and right side edges, the first groove structure 12 and the second groove structure 13 are flush.

< variation example 3 of the first example >

Fig. 12 shows a perspective view of a substrate according to modified example 1.

In the first example, the second groove structures 13 extend outwardly from four sides of the first groove structure 12 to the outside of the first groove structure 12. However, as shown in fig. 12, in modified example 3, the second groove structure 13 extends outward from one side of the first groove structure 12 to the outside of the first groove structure 12, but does not extend outward from the remaining three sides (in this example, the upper side, the lower side, and the left side) of the first groove structure 12.

As can be seen from fig. 12, the first groove structure 12 and the second groove structure 13 are flush at the upper, lower and left side edges.

< other modified examples of the first example >

In the above first example and its modified examples 1 to 3, a plurality of support positions are provided at four corners along the periphery of the first groove structure. However, as long as these support positions can support the chip in the vertical direction, the number of these support positions may be more or less, and the arrangement position may not be limited to the corner position. For example, a support location may also be provided at a central portion of any edge of the first groove structure, and/or a support location at one or both respective corners of the edge may be omitted.

In addition, in the above first example and its modified examples 1 to 3, the first groove structure has a planar shape of a square. However, since the chip may also have other shapes than square, the first groove structure may also have other shapes than square, such as rectangular, triangular, hexagonal, circular, etc. In this case, in general, a plurality of support positions may be appropriately provided along the periphery of the first groove structure to be able to support the chip in the vertical direction. In addition, similar to the first example and its modified examples 1 to 3, the second groove structure may also extend outward from at least a portion of the periphery of the first groove structure between the plurality of support positions.

Second example of the substrate

Fig. 13 shows a substrate according to a second example of the present invention. A second example is an improvement of the first example.

As shown in fig. 13, a high thermal conductivity heat conduction stage 5 for conducting heat from the chip 3 is further provided in the second groove structure 13 for improving the thermal performance of the package structure. Besides, other configurations of the substrate according to the second example may employ the configurations of the first example and its modified examples.

For example, the thermally conductive stage 5 may be a portion of material that is intentionally left when forming the second recess structure 13 in the substrate 1. At this time, the material of the heat conduction stage 5 is the same as that of the substrate. Since the thermal conductivity of copper is 7 to 8 times higher than that of tin, the thermal conductivity can be improved by forming the high thermal conductivity heat conduction stage 5.

The upper surface of the heat conducting table 5 is at most flush with the bottom of the first groove structure 12, i.e. does not exceed the bottom of the groove structure 12 in height. The heat conductive stage 5 is formed below the heat generation position of the wavelength conversion chip, that is, below the region for receiving and converting the excitation light. The shape of the upper surface of the heat conduction stage 5 corresponds to the spot shape of the excitation light, and may be any shape such as a square, a rectangle, or a circle. Further, the upper surface area of the heat conduction stage 5 is slightly larger than the area of the region of the wavelength conversion chip that receives the excitation light.

In the reflow soldering process, a very thin layer of solder paste is formed between the heat conducting stage 5 and the wavelength conversion chip 3 under vacuum and capillary forces. At this time, the strength of the wavelength conversion device is not reduced, but the thickness of the solder paste at the light spot is reduced, thereby greatly reducing the thermal resistance of the solder paste.

In addition to the above-described effects, the substrate according to the second example can obtain the same action and effects as those of the first example and its modified example.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited thereto, and those skilled in the art will appreciate that various changes, combinations, sub-combinations, and modifications may be made without departing from the spirit or scope of the invention as defined in the appended claims.

Claims

1. A substrate, comprising:

a substrate body having a bonding surface to which a member to be bonded is bonded with a bonding material;

a first groove structure formed in the engaging surface and having an opening size equal to a size of the engaged member to enable positioning of the engaged member in a planar direction of the engaging surface; and

a second groove structure for accommodating the joining material, the second groove structure being formed in the first groove structure and having a second depth such that the first groove structure has a first depth smaller than the second depth only at a plurality of support positions along a periphery capable of supporting the joined member in a vertical direction;

a heat conducting stage for conducting heat from the engaged components is disposed inside the second groove structure, and a top surface of the heat conducting stage is at most flush with a bottom of the first groove structure.

2. The substrate of claim 1, wherein the first depth is equal to or less than a thickness of the engaged components.

3. The substrate of claim 1, wherein the first groove structure has a square planar shape.

4. The substrate of claim 3, wherein the plurality of support locations are locations at four corners of the first groove structure.

5. The substrate of claim 1, wherein the first groove structure has a square planar shape, the plurality of support locations are locations at four corners of the first groove structure, and the second groove structure extends from at least one side of the first groove structure to an exterior of the first groove structure.

6. The substrate of claim 5, wherein the second groove structure extends from four sides of the first groove structure to an outside of the first groove structure and has a cross-shaped planar shape.

7. The substrate of claim 6, wherein the second groove structure has a width less than a width of the first groove structure and a length greater than the width of the first groove structure.

8. The substrate according to claim 1, wherein a position of the heat conduction stage corresponds to a heat generation position of the joined members.

9. The substrate of claim 1, wherein the planar shape of the thermally conductive stage is one of square, rectangular, and circular.

10. The substrate of claim 1, wherein the bonded component is a wavelength conversion chip.

11. The substrate of claim 1, wherein the bonding material is solder paste.

12. A method of forming an encapsulation structure using the substrate of any one of claims 1 to 11, the method comprising:

providing the substrate;

printing bonding material to a bonding surface of a bonded member;

mounting the part to be joined at the first groove structure of the substrate in such a manner that a joining surface of the part to be joined faces the substrate;

placing a weight on the engaged member;

placing the combination comprising the base plate, the part to be joined and the weight block obtained at this time in a vacuum eutectic furnace for welding to allow the bonding material to flow freely in the second groove structure of the base plate; and is

After the welding is completed, the weight block is removed.

13. A package structure, the package structure comprising:

the substrate according to any one of claims 1 to 11;

an engaged member; and

a bonding material for bonding the bonded member to the bonding surface of the substrate.