JP3214638B2 - Ceramic lid for semiconductor package and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic lid for a semiconductor package, and more particularly, to a semiconductor device in which a semiconductor element is housed in a package body, and then covered by the body and joined by soldering. The present invention relates to a ceramic lid for sealing a semiconductor element.

[Prior art]

[0002] This type of ceramic lid (hereinafter simply referred to as "lid") is disclosed in Japanese Patent Application Laid-Open No. 57-1601.
The technology disclosed in Japanese Patent Publication No. 47-76 and Japanese Patent Publication No. 3-76784 is known. In these technologies , FIG.
As shown in (A) , the lid 51 is provided with the package body 5.
A solder layer 54 is formed flatly on the periphery of the surface facing the surface 2 with a metallized layer 53 interposed therebetween.
As shown in FIG.
And is melted by heating to a predetermined temperature and soldered (sealed).

[0003]

By the way, the solder is
When heated, it begins to melt at the solidus temperature and becomes semi-molten, and when it exceeds the liquidus temperature, it completely dissolves. Therefore, the sealing in the above-mentioned conventional technology is performed under a condition set at a temperature slightly higher than the liquidus temperature (hereinafter, also referred to as “soldering temperature” or “sealing temperature”). In this case, when the solder 54 of the lid 51 set in the package body 52 begins to melt above the solidus temperature, the solder simultaneously acts as a seal (sealing material).
At that stage, the inside of the package becomes almost airtight. The package is then further heated to the sealing temperature under that condition.

[0004] For this reason, at the sealing temperature, the inside of the package becomes relatively remarkably high pressure due to the thermal expansion of the gas, and the semi-molten or molten solder is pushed outward (outside the package), and the amount of the solder is slightly increased. However, as shown in FIG. 4B, there is a problem in that the particles 56, 56 are scattered outside, and a part 56, 56 adheres to the outer leads 57 and the like. In other words, when the above-described conventional lid 51 is used, in the soldering process, a defective product having a serious defect such as a poor appearance or a problem with the insulation and a required function of the package is not satisfied is likely to occur. As a result, there has been a problem that the production unit price has been increased.
Incidentally, in the case of a large package, since this has a large effect on the yield, ceramic lids are not often used. In fact, it was necessary to use expensive parts constructed by welding reforms. The present invention has been devised in view of the above points, and an object of the present invention is to provide a lid which can prevent the molten solder from scattering in a soldering process.

[0005]

According to the present invention , there is provided a semiconductor package for a semiconductor package according to the present invention .
Ceramic lid is a ceramic lid for sealing by soldering the package body containing a semiconductor, Li on the side facing said package body
A metallized layer provided annularly on the surface of a pad substrate;
A metallized layer of the lid substrate, wherein the metallized layer is integrally provided with a solder layer formed on the tallized layer.
The provided surface is formed flat, and the solder layer is provided with a concave portion in which gas flow is held inside and outside of the package when the lid is covered on the package body.
In addition to the above, the recess has a solder layer at the bottom of the groove.
The solder layer is provided continuously in a ring shape .

[0006]

According to the above structure, when the lid according to the present invention is used, the lid is put on the package body,
The inside of the package is immediately sealed by the recesses in the solder layer, even when the heating progresses in the reflow furnace to reach the solidus temperature, and even when the solder begins to melt and becomes a semi-molten state, the recess provided in the solder layer There is no. Therefore, at this stage, the gas is in a state of flowing in and out, and the gas expanded inside is released to the outside. That is,
Unlike the conventional case, the inside of the package is not sealed at the same time as the solidus temperature of the solder,
The temperature at which the gas inside and outside is flowing can be closer to the liquidus temperature of the solder. Therefore, the internal pressure is reduced or prevented accordingly.

On the other hand, when the heating further proceeds and the solder is completely melted in the vicinity of the sealing temperature , the concave portion is formed by the flow.
It is flattened (uniform) and the inside is kept airtight. Thereafter, sealing is performed at the sealing temperature. As described above, in the present invention, since the gas inside the package does not have a high pressure relative to the outside as in the related art, the scattering of solder in the soldering process and the occurrence of the above-described defects caused by the solder are prevented. . In addition, in the present invention, the recess
Has a solder layer also at the bottom of the groove, and the solder layer
It is provided continuously. In other words, the annular solder layer
And the solder is continuous even in the concave part,
Easily flows to fill the recess after melting and forms the recess
Poor solder inflow at locations is prevented. Sa
Further, in the present invention, the above-described method of forming the ceramic lid substrate is performed.
The surface on which the tally layer is provided is formed flat, and the solder layer
The recess is formed by providing a partial difference in the thickness of
You. In other words, the recess in the present invention is provided only in the solder layer.
Therefore, a concave portion is provided in the lid substrate.
It does not require the step of cutting. For this reason, for example, ceramic
By providing a recess in the lid substrate, a recess is provided in the solder layer.
Recessed on the ceramic lid substrate
The cost is greatly reduced because the process of providing
You. Also, in the present invention, the metallized layer of the lid substrate
Since the surface provided with is formed flat, the lid
Compared to a structure with a recess in the substrate, the lid is
Very good airtightness after sealing in cage
It becomes possible. The semiconductor package according to claim 2 of the present invention.
The method for manufacturing a ceramic lid for a die is described in claim 1.
On the ceramic lid for the semiconductor package
Upon providing the recesses in the solder layer, the Metara
Of the ceramic lid substrate provided with the
A solder base layer is selectively formed only on the rise layer,
A portion forming the concave portion in a form in which the concave portion is provided on the base layer.
Screen printing of the solder paste except for the solder paste
Reflow the paste while keeping the concave shape,
It is characterized in that the recess is provided by solidifying as it is
And The semiconductor package according to claim 3 of the present invention.
A method for manufacturing a ceramic lid for a cage is described in claim 1.
The ceramic lid for the semiconductor package described in
Upon kick providing the recesses in the solder layer, the main
Of a ceramic lid substrate provided with a
A solder layer is formed flat on the metallized layer, and then
A part of the solder layer is provided with the recess by cutting.
It is characterized by that. Further, according to claim 4 of the present invention.
Method of manufacturing ceramic lid for semiconductor package
Is a ceramic for a semiconductor package according to claim 1.
To provide the recess in the solder layer of the lid made of
Or a ceramic resource provided with the metallized layer.
A solder layer is formed flat on the metallized layer of a printed circuit board.
Then, a part of the solder layer is pressed to
It is characterized in that the concave portion is provided. Further, the contract of the present invention
A ceramic package for a semiconductor package according to claim 5.
The method for manufacturing a semiconductor package according to claim 1, wherein
The recess in the solder layer in the ceramic lid of
In providing the ceramic, the ceramic having the metallized layer is provided.
A solder layer on the metallized layer of the lid substrate made by Mick
Form flat, then put a bar on the solder layer
Reflow and insert the bar into the solder
It is characterized by providing a concave portion. Such a contract of the present invention
6. A ceramic package for a semiconductor package according to claim 2.
According to the method for manufacturing a lid,
Easy production of ceramic lids for semiconductor packages
it can.

[0008]

Next, a first embodiment of the present invention will be described in detail with reference to FIGS. The ceramic lid 1 of this example is a ceramic substrate 2 (one side: about 20 mm, thickness: about 1 mm) formed in a substantially square shape .
A predetermined metallized layer 3 is provided in an annular shape along the outer peripheral edge of one surface of the flat plate ), a solder layer 4 is formed thereon, and a central portion along each side of the lid of the solder layer 4 is formed. On the other hand, recesses 5 and 5 each having a rectangular cross section are formed in four notches so as to cross the inside and outside. Here, the depth of the groove of the concave portion 5 in the solder layer 4 up to the groove bottom 5a is
The depth D and the width W need to be large enough not to fill the recess 5 at least in a semi-molten state near the solidus temperature. In this example, they are set as follows. .
That is, the solder layer 4 has a thickness T of 150 μm, a groove depth D of 50 to 75 μm, and a width W of 1 mm. The width of the solder layer 4 is about 1.5 mm. Further, the lid 1 of this example is press-formed by a known means.
0% alumina is fired, and the metallized layer 3
Screen-prints the Ag-Pd paste and then
It is formed by firing.

On the other hand, the solder layer 4 is formed by immersing the substrate 2 in molten solder, selectively forming a solder base layer only on the metallized layer 3, and providing recesses 5 and 5 on the base layer. , Screen printing of the solder paste several times (two times) excluding that part, passing this through a reflow furnace controlled to a predetermined temperature, and reflowing while maintaining the concave shape,
The solder layer 4 having the concave portions 5 and 5 is solidified (solidified) as it is. Incidentally, the reflow temperature is preferably in the range from the liquidus temperature to the same temperature plus 10 ° C. or less. However, the solder used in this example has a composition of 85% by weight of Pb, 5% by weight of Sn, 7% by weight of Bi, and the balance of Ag and In.
° C and the liquidus temperature is 280 ° C.

Next, the lid 1 according to the present embodiment having the above configuration will be described.
The operation and the like will be described. As shown in FIG. 2, the solder layer 4 is brought into a predetermined temperature (300 ° C. in this example) in a reflow furnace (not shown) while the solder layer 4 is positioned and closely contacted so as to match the metallized layer 12 formed on the package body 11. In this case, when the lid 1 is set on the package main body 11, in this case, between the solder layer 4 and the metallized layer 12 of the package main body 11 (joining surface portion),
The recess 5 forms a tunnel through which gas inside and outside the package flows. As a result, the gas expanding in the package exits through the recess 5 as shown by an arrow in FIG. In this example, this state is maintained until the liquidus temperature is reached, though the communication hole of the concave portion, that is, the gas flow path area gradually narrows. In other words, the concave portion 5 provided in the solder layer 4 is set so as to be almost at the liquidus temperature and to be flowed and flattened. The released gas is released to the outside.

Thus, when the temperature exceeds the liquidus temperature, the solder is completely melted and closes the concave portions 5 and 5, so that the sealing temperature (30 ° C.)
At 0 ° C.), the internal pressure rise can be kept low. Thereafter, after cooling and solidification of the solder, a desired semiconductor package can be obtained. in this way,
In this example, there is no abnormal increase in internal pressure due to the start of sealing almost simultaneously with the start of melting of the solder as in the conventional lid, and the scattering of the solder is prevented. In addition, solder
The layer 4 is provided continuously in a ring shape, and the solder layer 4
Since the solder is also continuous in the recess 5, the recess 5 is filled.
Since the molten solder easily flows back in,
The occurrence of solder inflow failure at the formation point is prevented.
Moreover, the metallized layer 3 of the lid substrate 2 is provided.
The surface of the solder layer 4 is formed flat, and the thickness of the solder layer 4 partially differs.
The recess 5 is formed by providing
Reference numeral 2 may be a substantially square flat plate having a certain thickness made of ceramic.
That is, the manufacturing process of the ceramic lid substrate 2 is duplicated.
For example, a concave portion is provided in this substrate because it does not cause complication.
Therefore, compared to the technology of providing recesses in the solder layer,
Dramatic cost reduction as no process of providing recesses is required
It is planned. Also, a metallized layer 3 of the lid substrate 2 is provided.
Is flat, so that the lid substrate has a concave
Lid 1 sealed in a semiconductor package
It is also effective for improving the airtightness later.

Table 1 shows the specific effects of preventing the scattering of solder in this embodiment. Table 1 shows the results of tests on the relationship between the depth D of the groove and the scattering of the solder, using a sample in which the size of the cross-sectional shape of the concave portion 5 was changed. However, the solder had the same composition, the thickness T of the solder layer 4 was 150 μm, and the width W of the groove of the concave portion was 1 mm (constant) (see FIG. 3). As shown in Table 1, the concave portions (concave portions)
In the comparative example without the groove , the solder was scattered in 60% of the samples. However , in the case of the concave portion, the scattering could be reduced to 0 to 20%. These things demonstrate the effects of the present invention.

[Table 1]

Further, the concave portion 5, the thickness T of the solder layer 4 and 150 [mu] m, the depth D of the groove under which the 50～75Myuemu, testing the relationship between the solder scattering by changing the width W of the recess I tried. Table 2 shows the results.

[Table 2] From this result, it can be seen that there is no scattering when the groove width W is in the range of 1.0 mm or more. However, when the groove width W is 10.0 mm, the appearance defect in which the meniscus becomes small was observed. It seems to be due to the relative lack of solder volume. From Tables 1 and 2, it can be seen that in the solder layer of this example ,
It is understood that the depth should be 50 to 75 μm and the width should be in the range of 1.0 to 5 mm.

In the present invention, the groove width of the concave portion may be appropriately set according to the type of the lid (package body) and the composition of the solder. In the case of solder composition difference solidus temperature and the liquidus temperature is high, while a <br/> and effective as large as possible a recess, the solder of small composition of the temperature difference
The depth and width of the concave portion can be set smaller as the concave portion becomes smaller, but it is set so that the sealing is generated as close to the liquidus temperature as possible. In addition,
As the solder layer formed on the lid, the above-mentioned Pb-Sn
In addition to the system solder, an appropriate solder may be used according to the type of the lid (package body), such as an Au-Sn system gold solder (gold system low-temperature brazing material).

Further, in the present invention, the cross-sectional shape and the number of the concave portions , or the locations of the concave portions can be appropriately set. On the other hand, the cross-sectional shape of the recess (groove) provided in the solder layer
However, the present invention is not limited to the above-described rectangular cross-section, such as an arc-shaped cross-section or a V-shaped cross-section . In addition,
The lid according to the present invention can of course be used in various packages.
Page.

A technique for providing a concave portion in the solder layer of the lid is provided.
Te, in addition to those described above, and a variety of techniques.
For example, a part of the flat solder layer can be provided by cutting (groove) processing or pressing in the next step. Alternatively, a stainless steel or ceramic rod may be placed on a solder layer provided flat by dip or printing and reflowed, and the rod may be cut into the solder, or the top and bottom may be reversed. It is also possible to reflow in the state. Alternatively, it can be provided by dissolving a part of the solder layer with a hot knife .

[0017]

As is apparent from the above description, when the package body is sealed with the lid according to the present invention , the conventional structure is provided by the concave portion provided in the solder layer .
As described above, the solder is heated to the solidus temperature and becomes a semi-molten state, and at the same time, the inside of the package is not sealed, and the temperature at which the gas inside and outside is flowing can be closer to the liquidus temperature. . Therefore, it is effective to prevent the internal pressure from being increased, and is effective to prevent the scattering of the molten solder and the occurrence of defects due to the scattering. In addition, in the present invention, the concave portion is also provided with a solder layer at the bottom of the groove.
Is present and the solder layer is provided continuously in a ring.
And easily flows to fill back the recess after melting
And prevents inflow of solder at the recess
Is stopped. That is, according to the lid of the present invention, occurrence of poor appearance of the package and poor electrical insulation is reduced,
It is possible to improve quality and reduce manufacturing cost. Because of such an effect, ceramicization is also suitable for a lid of a large package that has been unsuitable in the past, so that a significant reduction in manufacturing cost is expected.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a ceramic lid for a semiconductor package according to the present invention, as viewed from a solder layer (bottom surface) side.

FIG. 2 is a partially broken sectional view showing a state where the lid of the first embodiment is put on a package body.

FIG. 3 is a partial front view of a concave portion of the lid of the first embodiment.

4A and 4B are views illustrating a conventional lid, in which FIG. 4A is a partially broken cross-sectional view showing a state in which the lid is placed on a package body, and FIG. 4B is a view after the package is sealed by soldering. FIG. 3 is a partially broken cross-sectional view illustrating a state in which solder is scattered.

[Explanation of symbols]

1, 21 lid 2, 22 lid ceramic substrate 3, 23 metallization layer 4, 24 solder layer 5 solder layer recess 5a recess groove bottom 11 package body 25 solder layer protrusion

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukihiro Aoyama 14-18 Takatsuji-cho, Mizuho-ku, Nagoya Japan Special Ceramic Industry Co., Ltd. (56) References JP-A-61-156842 (JP, A) 3-145747 (JP, A) JP-A-6-132413 (JP, A) JP-A-63-15052 (JP, U) JP-A-63-84956 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 23/02-23/10

Claims (5)

(57) [Claims] 1. A lid made of ceramic for sealing a package body containing a semiconductor by soldering , the lid substrate facing the package body.
Metallized layer provided annularly on the surface of
In made integrally includes a solder layer formed on the layer, surface on which the metallized layer is provided in the lid substrate flat
And a recess for holding a gas flow inside and outside the package when the lid is placed on the package body with respect to the solder layer, and the recess is formed at the bottom of the groove.
There is also a solder layer, and this solder layer is provided continuously in an annular
It is characterized in that is, ceramic lid for a semiconductor package. 2. The semiconductor package according to claim 1, wherein
The concave portion is formed in the solder layer of the ceramic lid.
In providing, the ceramic lid base provided with the metallized layer is provided.
Selectively form a solder base layer only on the metallized layer of the plate
And forming the recess on the base layer.
Screen printing of solder paste except for parts that make up
Then, the solder paste is removed while maintaining the concave shape.
The concave portion is provided by allowing it to flow and solidifying as it is.
Ceramic for semiconductor packages characterized by the following:
Method of manufacturing lid made of. 3. The semiconductor package according to claim 1, wherein
The concave portion is formed in the solder layer of the ceramic lid.
In providing, the ceramic lid base provided with the metallized layer is provided.
Forming a solder layer flat on the metallized layer of the plate,
Thereafter, a part of the solder layer is cut to form the concave portion.
Characterized by providing a ceramic package for a semiconductor package.
Method of manufacturing Mick lid. 4. The semiconductor package according to claim 1, wherein
The concave portion is formed in the solder layer of the ceramic lid.
In providing, the ceramic lid base provided with the metallized layer is provided.
Forming a solder layer flat on the metallized layer of the plate,
Then, the recess is formed by pressing a part of the solder layer.
A ceramic for a semiconductor package characterized by being provided.
Method of manufacturing a lid made of a plastic lid . 5. The semiconductor package according to claim 1, wherein
The concave portion is formed in the solder layer of the ceramic lid.
In providing, the ceramic lid base provided with the metallized layer is provided.
Forming a solder layer flat on the metallized layer of the plate,
After that, a bar is placed on the solder layer and reflowed.
That the recesses are provided by making the solder bite into the solder.
Characteristic ceramic lid for semiconductor package
Manufacturing method.