JP3432988B2 - Metal lid substrate for electronic component package and method of manufacturing metal lid - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal lid substrate for an electronic component package and a method for manufacturing the metal lid, and more particularly to an electronic device such as a crystal resonator, a SAW filter, a transistor, an IC. A metal lid substrate (hereinafter, also referred to as a lid substrate or simply a substrate ) used for a package that seals components , and a metal lid (hereinafter, simply a lid).
(Also referred to as “de”) .

[0002]

2. Description of the Related Art As a metallic lid of this type, Fe--
Ni-based alloys (42 alloy, Fe-Ni-Co alloy, etc.)
It is well known that a metal substrate made of Ni is plated with Ni (nickel). When the lid is used to perform sealing by the seam weld method, the lid is covered with a weld ring formed on the sealing surface (lid contact surface) of the package body and sealed one by one by resistance welding. However, the difficulty is that a large amount cannot be processed at one time.

On the other hand, in the method of sandwiching the solder preform between the lid and the package body and performing reflow sealing, it is excellent in mass productivity because it can be sealed by passing through a reflow furnace, but the lid Workability is difficult because it is necessary to set a preform to cover it. Moreover, since the preform itself is expensive, the sealing cost is increased. Furthermore, since the entire surface of the lid on the sealing surface side is easily wetted by solder, the molten solder during reflow is inside (or outside) the solder sealing portion on the sealing surface side.
It is easy to get wet and spread. For this reason, soldering for sealing becomes less and the airtightness lowers, a part of the solder may come into contact with the bonding wire, and serious defects such as dripping on electronic parts such as IC are likely to occur. was there.

As a lid for solving such a problem, there is a lid described in Japanese Patent Application Laid-Open No. 4-96256. And
In this publication, Ni formed on the sealing surface of the lid substrate
A portion of the layer near the outer periphery forming the solder sealing portion (hereinafter, also referred to as the solder sealing portion) is covered with an aluminum plate and irradiated with YAG laser to oxidize the portions other than the solder sealing portion. There is disclosed a technique in which the surface is roughened so that the wettability of the solder at that portion is made lower than that of the solder sealing portion. That is, in this product, the inner surface surrounded by the solder sealing portion has a lower wettability of the solder than the surface of the solder sealing portion to prevent the wet spreading of the solder at the time of sealing. It was designed to prevent problems.

[0005]

[Patent Document 1] Japanese Patent Application Laid-Open No. 4-96256
In the lid described in the publication, a large amount of sealing treatment can be performed at one time, and the inner surface surrounded by the solder sealing portion is oxidized to reduce the wettability of the solder. It also prevents the solder from spreading wet. However, in the above-mentioned lid, since the oxidation for reducing the wettability of solder is performed by laser irradiation, there is a problem that the process is troublesome and the cost becomes high. Moreover, although the wettability of the solder on the surface other than the solder-sealed portion is low, the Ni layer of the solder-sealed portion itself is not subjected to any special treatment, so that the wettability of the solder is insufficient and Since the Ni layer surface may be oxidized, there is a problem that soldering cannot be performed stably.

The present invention has been devised in view of the above problems, and not only can prevent the sealing solder from spreading from the solder sealing portion to the inside of the sealing surface, but also
A metal lid substrate that can be oxidized easily and at low cost to prevent wetting and spreading, and has excellent solder wettability in the solder sealing part and stable soldering.
It is an object of the present invention to provide a manufacturing method capable of efficiently manufacturing a metal lid at low cost.

[0007]

In order to achieve the above object, the present invention provides a metal lid substrate for an electronic component package having a Ni plating layer formed on at least one principal surface thereof. Outer peripheral part that forms the solder sealing part in
The outer peripheral edge of the substrate is entirely inward from the outer peripheral edge of the substrate.
Side, and the outer peripheral side forming the solder sealing part.
It is characterized in that the Ni plating layer in the region excluding the copper portion is thermally oxidized, and an Au (gold) plating layer is formed on the Ni plating layer in the region near the outer periphery. Here, the “solder sealing portion” refers to a surface on which sealing solder is formed or a surface which is wet with solder for sealing. The area excluding the outer peripheral portion may be not only on the inner side surrounded by the same portion but also on the outer side thereof. Furthermore, “thermal oxidation” is the N exposed by being heated in an oxidizing atmosphere such as the atmosphere or oxygen.
This means that the i plating layer is oxidized.

In such means, the wettability of the solder is lowered by thermal oxidation, so that the substrate can be manufactured easily and at low cost. Further, since the Au plating layer is formed on the outer peripheral portion forming the solder sealing portion, N
Wetting of the solder is better than in the case of i plating,
Moreover, since the surface is not oxidized, the storage stability is good, and therefore soldering can be performed stably.

In the above means, the thermally oxidized area of the inner Ni plating layer surrounded by the outer peripheral portion forming the solder sealing portion may be a portion along the outer peripheral portion.
That is, the thermally oxidized region does not have to be the entire inner surface surrounded by the solder sealing portion, and a predetermined portion along the inner peripheral edge of the solder sealing portion as long as the molten solder can be prevented from spreading inside. You can just do it.

Further, the Au of such a metal lid substrate is used.
According to the metal lid in which the sealing solder is formed on the plating layer (front surface), it is not necessary to set the solder preform one by one when covering the package body for sealing. Then, the solder does not wet and spread inside the solder-sealed portion of the lid, so that the airtightness is reduced, a part of the solder is in contact with the bonding wire, and
It does not hang down on C etc.

The preferred method for producing the metallic lid according to the present invention is as follows. That is, a lid substrate assembly in which a plurality of lid substrates are partially connected at their side edges is formed, and Ni plating is applied to both sides and side edge surfaces of at least each lid substrate portion forming the lid substrate assembly, and then A resist is applied to both surfaces and side edge surfaces, exposed and developed to expose the Ni plating layer at the outer peripheral portion of the lid substrate portion that forms the solder sealing portion.
Au plating is applied to the plating layer, the resist is then removed, and the exposed Ni plating layer is oxidized by heating in an oxidizing atmosphere. Sealing solder is formed on the Au plating layer of the portion, and thereafter, each lid substrate portion is cut at a connecting portion at its side edge. As a result, many metal lids with solder for sealing can be manufactured at one time. In addition, since the material of the substrate is exposed to the cut surface and is easily corroded from the cut portion of the connection portion on the side edge surface when cut, the cut area is as small as possible within a range that does not interfere with handling during manufacturing. Preferably.

The material of the lid substrate and the metal substrate forming the lid in the above is iron-nickel alloy (F
Although alloys containing iron and nickel as main components, such as e-Ni-Co alloys and 42 alloys, can be mentioned as preferable ones, those having a smaller coefficient of thermal expansion may be used depending on the ceramic material of the package body. . Further, in the present specification, Ni plating includes pure Ni plating and Ni-Co plating.
Ni-based alloy plating other than plating is included, and Au plating includes pure Au plating and alloy plating thereof.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a lid substrate according to the present invention will be described in detail with reference to FIGS. In the figure, reference numeral 1 denotes a lid substrate, which is configured as follows on the basis of a metal substrate (a thin plate of Fe—Ni—Co alloy in this example) 2. That is, in this example, the Ni plating layer 6 is formed on the entire surfaces of both (main) surfaces 3 and 4 and the side edge surface 5 of the metal substrate 2, and the outer peripheral portion of the one main surface 3 on the sealing surface side is predetermined. The solder sealing portion (hatching portion in FIG. 1) 7 is formed with a width of 1 mm, and the Au plating layer 8 is formed on the Ni plating layer 6 to form the lid substrate 1. However, in this example, the outer peripheral edge 7a of the solder sealing portion 7 (Au plating layer 8) is slightly inwardly d inward from the outer peripheral edge 2a of the substrate 2 over the entire periphery. The Ni plating layer 6 on the entire surface (both sides and side edge surfaces) of the substrate 2 excluding the solder sealing portion 7 is thermally oxidized, and an oxide film (Ni oxide layer) is formed on the surface.

The lid substrate 1 of the present embodiment as described above is an electrolytic N
After i plating, a resist is applied on the entire surface, exposed and developed to expose the Ni plating layer only at the portion forming the solder sealing portion 7, Au plating is performed on the Ni plating layer 6, and then the resist is removed. The exposed Ni plating layer 6 is thermally oxidized by heating in an oxidizing atmosphere to make the solder hard to wet.

As described above, in this embodiment, the oxidation of the Ni plating layer 6 for lowering the wettability of the solder is performed by thermal oxidation, so that the treatment can be simplified. Further, since the Au plating layer 8 is formed on the solder sealing portion 7, the solder wets better than when the Ni plating is left as it is. Moreover,
Since it has good storage stability, it can be soldered stably.
The quality and sealing performance of the lid substrate 1 can be improved.

Further, as shown in FIG.
By forming the sealing solder 9 on the u-plated layer 8, the metal lid 11 with solder is formed. The sealing solder 9 can be formed, for example, by printing a solder paste and reflowing. In addition, in FIG. 1, the Ni plating layer in the entire area except the solder sealing portion 7 was thermally oxidized. However, in the area of the Ni plating layer inside the solder sealing portion 7, the inflow of the molten solder is prevented. As long as it can be prevented, only the portion along the solder sealing portion 7 may be thermally oxidized without thermally oxidizing the central portion (for example, the portion surrounded by the two-dot chain line) in the figure.

As shown in FIG. 4, when the package body 21 having the same size and the same plane shape as that of the lid (substrate) 11 of this embodiment is sealed, the molten solder 9 is placed inside. Not only does it not spread, but also the drawn-down portion d from the outer peripheral edge of the lid 11 does not get wet with the solder. That is, since the outer peripheral edge 7a of the solder sealing portion 7 (Au plating layer 8) is pulled inward from the outer peripheral edge 2a of the substrate, the meniscus becomes as shown in the drawing, and the solder protrudes outward during sealing. To be prevented. Therefore, according to the lid (board) 11 of this example, there is no difficulty in handling due to the protrusion thereof, and it is also effective for positioning at the time of mounting on the circuit board and prevention of deterioration of reliability of the circuit board. Incidentally, the amount of pull-down d generally depends on the thickness and width of the sealing solder and the type of solder, but is preferably in the range of 50 to 500 μm.

Now, a preferred method for manufacturing such a lid will be described in detail with reference to FIGS.
First, a thin plate (0.1 mm in thickness, for example) made of a Fe—Ni—Co alloy is prepared, and as shown in FIG. 5, a plurality of lid substrates 1 and 1 are formed by etching or press punching. A lid substrate assembly (also simply referred to as an assembly) 31 that is partially connected at its side edges is manufactured. The assembly 31 of this example is a frame-like structure in which the periphery of each substrate 1 is left in a frame shape, leaving four connecting portions 32, 32 at the center of each side of the substrate 1. The respective connection parts 32, 32 connect and support the respective substrates 1, 1.

Then, the entire surface (both sides and side edge surfaces) of this assembly 31 is plated with Ni (electrolytic or electroless) to a predetermined thickness (for example, 1.0 to 2.0 μm) to perform corrosion resistance treatment. (See Figure 7B). Next, a resist R is applied to the Ni plating layer 6 (both sides of the assembly 31 and the side edge surfaces including the side edge surfaces 5 of the substrates 1 and 1) to a predetermined thickness (see FIG. 7C). Then, the substrate is exposed and developed so that the Ni plating layer 6 is exposed only at a portion (between the two-dot chain line in FIG. 6) forming the solder sealing portion 7 of each substrate 1 (see FIG. 7D). Then, the exposed Ni plating layer (solder sealing portion 7) 6 is subjected to Au plating (for example, a thickness of 0.3 μm) to form an Au plating layer 8 having a predetermined thickness (see FIG. 7E).

After that, the resist R is removed (see FIG. 7F), and a thermal oxidation treatment is carried out by passing through a heating furnace in the atmosphere of 400 to 600 ° C. In this treatment, the Au plating layer 8 is not oxidized, but the exposed Ni plating layer 6, namely A
An oxide film 6s is formed on the surface (both sides and side edge surfaces) of the assembly 31 other than the u-plated layer 8 (see FIG. 7G).

Then, the Au plating layer (solder sealing portion) 8
Then, screen print solder paste and reflow,
The sealing solder 9 is formed to a predetermined thickness (for example, 50 μm) (see FIGS. 7H and 8). At this time, since the solder does not wet (repell) the Ni oxide layer 6s, the solder is well formed only on the Au plating layer 8 of the solder sealing portion 7. After that, if the flux is removed and the connecting portions 32, 32 of the substrates 1, 1 in the assembly 31 are cut along the vertical and horizontal sides (side edges) of the respective substrates 1, 1, the metal shown in FIG. A large number of lids 11 can be obtained at one time. A metallic lid substrate can be obtained by cutting at the connecting portion 32 before forming the sealing solder 9.

As described above, according to the manufacturing method of this embodiment, the lid 11 according to the present invention can be efficiently manufactured. Therefore, it is extremely suitable for mass production. In particular, it is optimal for manufacturing small lids such as package lids used for crystal oscillators and the like. In the above example, the solder was formed by printing a paste and reflowing it. However, the present manufacturing method is not limited to this method, and may be formed by, for example, wave soldering.

In the lid cut from the assembly 31, the material of the substrate is exposed on the cut surface (connecting portion) of the side edge of the lid 31 and is easily corroded, so that the connecting portion 32 is not affected in the manufacturing process. It is preferable to make the width of the as small as possible so that the cutting area becomes smaller. Moreover, the connection part 3
Regarding the number of 2, in this example, there are four, respectively,
For the same reason, it is preferable that the amount is as small as possible. In the above, the Ni plating on the main surface opposite to the sealing surface does not have to be oxidized.
Au plating may be applied to the i-plated layer.

Also in the present manufacturing method, the entire surface of the inner Ni plating layer surrounded by the solder sealing portion (sealing solder) 7 was oxidized. It suffices to prevent wetting and spreading (flow-in) to the inside. Therefore, do not oxidize the entire surface with a predetermined width along the inner peripheral edge of the solder sealing part, and do not oxidize the center and its vicinity. May be. In addition, the arrangement pattern (cutout shape) of the substrates in the aggregate, the number of taken pieces, and the like may be designed in an appropriate shape and number.

[0025]

According to the metallic lid substrate of the present invention, since the Ni plating layer is oxidized by thermal oxidation, the lid substrate in which the solder does not wet and spread can be obtained at low cost. In addition, since the solder-sealed portion is plated with Au, the solder wets better than when it remains Ni-plated, and since it does not oxidize, it has good storage stability, and therefore soldering is stable. You can do it.

Further, the metal lid substrate according to the present invention is
The Au plating layer near the outer periphery forming the solder sealing portion has a sealing solder.
According to the metal lid formed with the solder, the lid with solder does not require setting of the solder preform for sealing. Further, unlike the seam weld method or the like, since the sealing can be collectively processed, the workability and mass productivity are improved, and the cost is reduced. In addition, the solder does not spread inside the lid at the time of sealing, and since the solder sealing part is plated with Au, the wettability of the solder is good,
High sealing performance is expected.

Further, according to the method of manufacturing a metal lid according to the present invention, each step (plating step, sealing solder forming step, etc.) is performed for each lid board assembly in which a plurality of lid boards are integrated. Since the above process can be performed, a large number of lids can be efficiently manufactured. Moreover, since the oxidation is performed by thermal oxidation, the oxidation process is simplified, and thus the manufacturing cost of the lid can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of a metal lid substrate according to the present invention viewed from a sealing surface side.

FIG. 2 is a central cross-sectional view of the metal lid substrate shown in FIG.

FIG. 3 is a solder sealing portion of a metal lid substrate according to the present invention.
The sealing solder is formed on the Au plating layer near the outer periphery
Sectional drawing of the metal lid which becomes.

FIG. 4 is a partial cross-sectional view illustrating a state where the package body is sealed with the metal lid of FIG.

FIG. 5 is an explanatory plan view of an assembly of lid substrates for explaining an embodiment of a method for producing a metal lid according to the present invention.

6 is a partially enlarged view of FIG.

7 is a cross-sectional view taken along the line AA of FIG. 6, where A is N
FIG. 3B is a schematic view showing before i plating, and B to H illustrating the manufacturing process from the Ni plating process to the formation of the sealing solder.

FIG. 8 is a view showing a state in which a sealing solder is formed in FIG.

[Explanation of symbols]

1 Metal lid board 3,4 Main surface 5 Side edge of board 6 Ni plating layer 7 Area near the outer periphery that forms the solder sealing part 8 Au plating layer 9 Sealing solder 11 Metal lid 31 lid board assembly 32 connection R resist

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Claims (4)

(57) [Claims] 1. A metal lid substrate for an electronic component package, having a Ni plating layer formed on at least one main surface thereof, the outer peripheral portion forming a solder sealing portion on the one main surface.
The outer peripheral edge of the substrate is entirely inward from the outer peripheral edge of the substrate.
Side, and the outer peripheral side forming the solder sealing part.
A metal lid substrate for an electronic component package, wherein the Ni plating layer in a region excluding the recessed portion is thermally oxidized, and the Au plating layer is formed on the Ni plating layer in the peripheral portion. 2. The thermally oxidized region of the inner Ni plating layer surrounded by the outer peripheral portion forming the solder sealing portion is a portion along the outer peripheral portion. Metal lid substrate for electronic component packages. 3. An outer periphery of a portion close to the outer periphery forming a solder sealing portion
The edge is pulled inward from the outer edge of the substrate all around.
The amount of falling is 50 to 500 μm
The electronic component package according to claim 1 or 2.
Metal lid substrate for Ji. 4. A lid substrate assembly in which a plurality of lid substrates are partially connected at side edges thereof is formed, and Ni plating is applied to at least both sides and side edge surfaces of each lid substrate portion forming the lid substrate assembly. Then, the resist is applied to both sides and side edge surfaces of the lid substrate, exposed and developed to expose the Ni plating layer at the outer peripheral portion forming the solder sealing portion in each lid substrate portion, and to the exposed Ni plating layer. Au plating is performed, and then the resist is removed and heated in an oxidizing atmosphere to oxidize the exposed Ni plating layer, and Au in the portion close to the outer periphery forming the solder sealing portion in each of the lid substrate portions is oxidized. A method of manufacturing a metal lid for an electronic component package, which comprises forming a solder for encapsulation on a plating layer, and thereafter cutting each lid substrate portion at a connection portion at a side edge thereof. .