JPH069508Y2 - Package for multiple power supply devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a semiconductor package for a multi-power semiconductor device that is small and can simplify power wiring.

(A) Prior art Semiconductor device packages are (1) plastic mold, (2) sardip, sir quad, and (3) multi-layer ceramic package MLC.
P) and the like.

(3) has a three-dimensional structure in which a plurality of ceramic plates are laminated and has a high degree of freedom in wiring. Good heat dissipation and airtightness. But it is expensive.

(1) is the most inexpensive and most frequently used package.
This is not suitable as a package for an element that handles high-speed signals or an element that generates a lot of heat.

(2) uses a ceramic plate, but does not have a laminated structure and has only a substrate and a lid. A lead frame or semiconductor element is attached on the substrate, and the lid is glass-sealed. Since it is mainly made of ceramic, it has good heat dissipation. It is cheaper than (3).

The present invention relates to improvement of packages included in the category (2).

FIG. 3 shows a glass-sealed hermetically sealed package structure according to a conventional example.

This hermetically sealed semiconductor device is a cerquad
Is called. It has been widely used with the progress of microcomputers and the like that are required to be thin.

Since the substrate and lid are ceramic, ceramic Cer
Is taking. Quad means attaching a lead frame to all four sides. Together called Cerquad.
Those with leads on two sides are called Cerdip.

If you want to get as many leads as possible, Cerquad with leads on all sides is suitable.

As the name suggests, ceramics such as alumina are predominantly used as the substrate for Squard. It has a track record of use. However, if high heat dissipation is required, the use of CuW, aluminum nitride (AlN), etc. as the substrate is being considered.

Sour quad packages are not called ceramic packages, even if they use ceramics.

Now, a manufacturing method for a mainstream ceramic substrate will be described.

The sealing glass 4 (low melting point glass) is applied to the four sides of the fired Al ₂ O ₃ plate, and the lead frame 2 is placed thereon. It is heated to melt the glass and bring it into a semi-molten state. The tip of the lead frame 2 sinks into the glass melt under its own weight. When this is cooled, the lead frame 2 is fixed in the sealing glass 4.

At this time, the upper surface of the tip portion of the lead frame 2 is almost flush with the glass surface.

In this way, the package is completed. Substrate 3 '
The semiconductor element 1'is placed and fixed in the center of the. The electrode portion on the upper surface of the element 1 ′ and the tip of the lead frame 2 are connected by the aluminum wire 5.

The lead frame 2 is radially fixed to the sealing glass 4 (low melting point glass) portion of the substrate 3 '. They are independent of each other and there is no special relationship between the lead frames.

Therefore, the connection between the electrode portion of the element 1'and the lead frame is arbitrary. The input signal line, output signal line, and power supply line may correspond to any lead frame.

All four sides have the same lead frame structure.

After mounting the element 1'and wire bonding, put a lid made of alumina with sealing glass on all four sides,
Apply to substrate 3 '. The sealing glass hits the tip portion of the lead frame 2 of the substrate 3 '. Heat in this state. The sealing glass melts and seals the lid and the substrate.

Since such a Cerquad package has an independent lead frame, it can be used for any device. It is a versatile package.

FIG. 3 shows a state in which only one lower side is wire-bonded. The other three sides are in a state before wire bonding, and the lead frame is simply attached radially.

(C) Problems to be solved by the invention Although the ECL element (Emitter Coupled Logic) is a Si semiconductor, it can be operated at high speed.

When operating at high speed, heat generation is remarkable. Therefore, heat dissipation becomes a problem. Therefore, Cerquad, Cerdip or ceramic laminated packages are used. The former two are more advantageous in terms of price.

There are various other problems when operating at high speed. You must also devise the signal line. It is also necessary to consider the power line.

The ECL device requires 3 power supplies. This is V _CC , V
_BB, written as _{V EE.} It does not mean that it is sufficient to use three electrodes for this.

When trying to operate at high speed, the impedance of the power supply line becomes a problem. This must effectively approach zero. For this reason, it is desired that the power line be thick and short.

In order to do this, pads for power supply are made in many places even for the ECL element, and a large number of leads for power supply are also provided for the package.

Then, the power supply line can be configured with a short wire and a short pattern. The effective impedance of the power line can be reduced.

Further, in order to stabilize the power supply potential and prevent noise from entering from the power supply line, it is necessary to insert a capacitor having a large capacity between the power supplies.

To provide many leads for power supply, for example, 3 on each side
Provide each power supply lead. In FIG. 3, V _CC , V
The leads for _BB and _VEE are written as C, B and E. Since there are three power sources, there are three C, B, and E leads on each side. If there are 9 leads for the input signal and the output signal, there are 9 + 9 = 18 leads, of which 9 are the leads for the power supply.

Too many leads for power supply. Since the spacing between leads is limited, the number of leads that can be attached is also determined when the size of the element is determined. I cannot attach many leads for input and output signals.

An external capacitor is connected between the power leads, but if the power leads are scattered in this way, it becomes difficult to attach the capacitors.

The larger the device size, the larger the package and the number of leadframes. Then,
It seems that the ratio of the number of leads for power supply can be reduced.

But not so. As the element size increases, the number of power supply pads on the element side also increases. Also on the package side
There must be four or five power leads instead of three on the sides.

After all, the ratio of the number of power supply leads to the total number of leads remains unchanged.

In the case of a ceramic laminated package (MLCP), a power supply surface is provided for each ceramic layer to reduce the number of power supply leads. This power supply surface is present on all four sides and can be reached by a short wire from any pad on the device. This is shown in FIG.

Such a thing is disclosed in Japanese Patent Application No. Sho 62-193 by the present applicant.
No. 80 (S.62.1.29 application), Japanese Patent Application No. 62-19
No. 811 (S.62.1.30 application) and the like.

In the case of a ceramic package, since a plurality of ceramic thin plates are stacked, a three-dimensional structure can be obtained, and such a thing becomes possible.

However, in the case of the circ quad, since it has a planar structure, it is not possible to provide a circulating power supply surface for each such layer.

The above problems are especially important for packages with many leads over 100.

(D) Structure In the package of the present invention, the loop-shaped metallized power supply lines corresponding to the required number of power supplies are formed on four sides around the element mounting part of the sirquad package substrate, and the lead frame
The device and the power supply pad of the device are connected by a wire.

Sealing glass is applied to the four edges of the substrate. A square ceramic frame is attached to a portion between the lead frame and the element mounting portion inside the sealing glass, and a looped metallized power supply line is formed on the ceramic frame.

The loop shape means that it is a closed curve. Metallizing is providing a metal layer on an insulator. Many are W layers coated with Au layers. Sometimes a Ni layer is added between them. This can be formed by a thick film printing method or a vapor deposition method. In the case of vapor deposition, Al, Ag, Au may be used.

Each of the lead frames is located outside the loop-shaped power supply metallization line, and the necessary lead frame and the loop-shaped power supply metallization line are connected by wires. Therefore, the power supply lead frame per side is
One for V _EE , V _CC , and V _BB .

Embodiments will be described below with reference to the drawings. FIG. 1 is a plan view of a package according to an embodiment of the present invention, and FIG. 2 is a vertical sectional view with a lid closed.

The substrate 3 is a square thin plate having an upper surface insulated.
This is often a ceramic (eg alumina Al)
₂ O ₃ ). Cu when heat dissipation is required
-W, AlN, etc. are also used. Since Cu-W is a conductor, in this case, an insulating film made of Al ₂ O ₃ , AlN, SiO ₂ or the like is provided on the upper surface to insulate the upper surface.

The central portion of the substrate 3 is the element mounting portion 7. The ECL element 1 is mounted later here. In this figure, the ELC element 1 is shown, but in the case of a package, the ECL element 1
Etc. are not installed yet.

A sealing glass, which is a low melting point glass, is applied in a square shape up to the outer edge so as to surround the element mounting portion 7. A thin, narrow ceramic frame 20 having a square shape is attached to the inner end. On the ceramic frame 20, a loop-shaped power supply metallized line 6 is formed in the number of power supplies in the shape of a square loop. In this example, since there are three power supplies V _EE , V _CC , and V _BB , the number of loops is three.

The tip of the lead frame 2 is fixed by the action of the sealing glass 4. This is the same as the conventional one. When the tip of the lead frame is put on the sealing glass 4 and heated, the glass becomes a semi-molten state, the tip of the lead frame sinks in the melt, and when cooled, it is fixed in this state. It is.

The supporting length of the lead frame 2 is shorter than that of FIG. The inner end of the lead frame 2 is not bent radially.

However, if the package substrate 3 is large, the sealing glass 4
The coating width of can be expanded more. In this case, the inner end of the lead frame 2 should be bent radially.

By the way, there are many lead frames around the edges. Of these, the lead frames close to both ends are selected by the number N of power supplies.
This lead frame is used as a lead frame for each power supply. If the number of lead frames on one side is M, (M-
N) is a lead frame for signals.

The leadframes for these signals are located inside.

In this example, since there are 3 power sources (N = 3), 3 out of 1 side
One lead frame is applied to V _EE , V _CC and V _BB .

These lead frames are written as E, C and B.

These lead frames are
Each loop-shaped power supply metallized wire 6c, 6b, 6e
Connected to.

The order inside the loop-shaped power supply metallized lines 6c, 6b, 6e is arbitrary.

By doing so, only one power supply lead frame is required per side.

The one shown in FIG. 3 required three lead frames per side. That is, it is possible to save two lead frames per side for each power source.

Further, in the present invention, each power source V _EE ,
1 lead frame connected to V _CC and V _BB
It can also be a book. In other words, choose 3 out of 4 sides,
A lead frame connected to V _EE , V _BB , or V _CC is designated for each of these sides.
In this way, the number of power supply lead frames in the entire package is only the number of power supply types. Select the outermost lead frame for the power supply.

FIG. 5 shows a schematic plan view of such a package.

(E) Function The ECL element 1 is die-bonded on the metallized layer 9 of the element mounting portion 7.

The electrode pads on the four sides of the device 1 are connected to the lead frame 2 and the loop-shaped power supply metallized line 6 by wire bonding.

In the case of an input signal and an output signal, the corresponding lead frame 2 and the pad 10 of the element are connected.

In the case of a power supply line, the power supply electrode pad 10 of the element and the corresponding loop-shaped power supply metallization line 6 are connected by wire bonding. Since the loop-shaped power supply metallized line 6 is provided on the four circumferences, any power supply electrode pad can be connected with a short wire.

Since the wire is thin, the value of the induction L is large. The shorter the wire, the lower the impedance.

The package of the present invention can reduce the number of leads, and reduce the ratio of the number of leads for power supply to the total number of leads.

This point will be described in more detail by comparing the examples shown in FIG. 3 and FIG.

This device has electrode pads 10 equally on four sides, and each side has 18 device pads for input / output signal, 9 V _EE electrodes, 3 V _BB electrodes, 3 V _CC electrodes, and 3 V _CC electrodes. To do.

In the conventional example shown in FIG. 3, the number of electrodes of the device is equal to the number of lead frames of the package. Therefore, the total number of lead frames is 72. Of these, 36 are lead frames for power supply. Half will be the lead frame for the power supply.

On the contrary, in the package of the present invention shown in FIG.
Power supply leadframes can be grouped together, one per side. Therefore, the number of lead frames for the power supply per side is reduced to three. If the number of signal lead frames is 9, the number of lead frames per side is reduced to 12. The total number is 48, of which only 12 are lead frames for power supply.

The total number of lead frames is reduced to 48/72 = 2/3 or 67%.

Since the number of lead frames can be reduced, if lead frames of the same width are provided at the same intervals,
The package can be made smaller.

Further, since the lead frame for the power supply is gathered in the corner of the package, it becomes easy to connect the external capacitor between the power supplies.

In the previous example, there were three power supply electrodes per side of the device. Two or more is effective in reducing leads.

Generally, it is assumed that the number of power supply electrodes per side of the device is n. It is assumed that the number of input / output signal electrodes per side is s. It is assumed that the required power source type is N.

In the conventional package, the total number of required leads Σ ₁ is Σ ₁ = 4nN + 4s (1).

In the present invention, the total number of leads Σ ₀ is Σ ₀ = 4N + 4s (2). The ratio of total leads is Is. The previous example is the case of s = 9, N = 3, and n = 3. It can be seen that this ratio becomes smaller than 1 when n is 2 or more.

Furthermore, as mentioned earlier, if there is only one lead frame for each power supply throughout the power supply (5th
Figure), the total lead number Σ _'0 is a N + 4s.

Therefore, the number of leads can be further reduced.

(F) Example I An alumina substrate was prepared by forming and firing by a conventional powder metallurgy method. Gold paste was printed and fired on the central portion of this alumina substrate to form the metallized layer 9 of the element mounting portion.

After that, the sealing glass 4 having a thickness of about 100 μm was applied onto the peripheral edges of the four sides of the substrate 3.

An alumina sintered body to be the ceramic frame 20 was attached to the inner edge of the sealing glass. On the alumina sintered body, what was to be the triple loop power source metallized wire 6 was formed by Al vapor deposition.

The lead frame 2 having Al vapor-deposited on the surface of the portion to be the connection portion was placed at a predetermined position. However, at this time, the lead frames 2 are all connected to each other on the outer side, and after the inner end of the lead frame is fixed, the outer frame portion is cut off.
This is well known.

The substrate 3 and the glass 4 were heated to bring the sealing glass 4 into a semi-molten state. The inner end of the lead sinks into the glass by its own weight, and the upper surface of the inner end of the lead becomes substantially flush with the glass surface.
As it cools, the glass solidifies again. The inner end of the lead frame was fixed on the substrate 3 by the sealing glass 4.

After this, the rear frame portion of the lead frame was cut off to separate the lead frame.

This completes the package. ECL
The element 1 was die-bonded to the element mounting portion 7 in the center of the alumina substrate 3. The electrodes of the three types of power sources of the ECL element 1 were connected to the corresponding loop-shaped power source metallizing lines 6 with the aluminum wires 5.

Furthermore, each loop-shaped power supply metallization line 6
As shown in the figure, each piece was connected to the outermost lead frame with an aluminum wire 5.

The signal electrodes on the ECL element were connected to other corresponding lead frames by aluminum wires.

Finally, a ceramic cap 8 having the same dimensions as the alumina substrate 3 and having a recess inside was pressed against the ceramic substrate 3 and heat-sealed.

The sealing glass 4 is also applied to the periphery of the ceramic cap 8. Since the sealing glasses are pressed against each other and heated,
Both become molten. When this is cooled, the ceramic cap 8 and the substrate 3 are firmly bonded. The joint is hermetically sealed with no air flow.

Thus, it was possible to accommodate the ECL element 1 having many power supply electrodes on the four sides in spite of the small number of leads.

This ECL element has 168 electrodes. 138 for signal
30 for power supply and 30 for power supply. In the case of FIG. 3, 168 lead frames are required, but 141 lead frames are sufficient in the present invention.

After confirming the initial operation with this package, a pressure cooker test (121 ° C, 2.3atm, 100H) was performed. When the operation test was conducted again, the defective rate was 0 for 30 packages.

(G) Example II A package of the present invention was made by using a substrate formed by forming an alumina thin film having a thickness of about 10 μm on a CuW plate instead of the alumina substrate. Since CuW is a conductor, an alumina thin film is attached to make the upper surface an insulator.

Since CuW has good thermal conductivity, it has better heat dissipation than ceramics.

A low melting point sealing glass 4 was applied to the four sides of the substrate. A ceramic frame (Al ₂ O ₃ ) 20 was attached.

The metallization layer 9 and the loop-shaped power supply metallization line 6 were formed by Al vapor deposition.

Thereafter, by performing the same steps as in Example I, it was possible to manufacture a hermetically sealed quad having a high heat dissipation characteristic.

(H) Effect Requires three or more types of power sources like the ECL element (N ≧
3) Moreover, when each type of power source has two or more power source electrodes on one side of the device (n ≧ 2), the package of the present invention is extremely effective.

According to this package, wiring can be simplified and the number of lead frames can be reduced. Then the package can be made smaller. In particular, the configuration shown in FIG. 5 is extremely effective.

The smaller the package, the more convenient and easy to implement. Further, since the package is small, the signal line can be shortened and the high speed characteristic is improved.

In addition, this package is an improvement of Sir Quad,
It is cheaper than a ceramic package (MLCP).

[Brief description of drawings]

FIG. 1 is a plan view of a package according to an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view in a state of being sealed with a cap. FIG. 3 is a plan view of a conventional circular quad package. FIG. 4 is a vertical sectional view showing an example of a multilayer ceramic package in which a power supply surface is provided for each layer. FIG. 5 is a plan view of a package according to another embodiment of the present invention. 1 ... ECL element 2 ... Lead frame 3 ... Substrate 4 ... Sealing glass 5 ... Aluminum wire 6 ... Loop-shaped power supply metallized wire 7 ... Element mounting part 8 ... Ceramic cap 9 ... Metallized layer 20 …… Ceramic frame V _EE , V _BB , V _CC …… Power supply E, B, C …… Lead frame connected to each power supply

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takatoshi Takigawa 1-1-1, Kunyokita, Itami City, Hyogo Prefecture Sumitomo Electric Industries, Ltd. Itami Works (72) Masaharu Yasuhara 1-chome, Koyokita, Itami City, Hyogo Prefecture No. 1 in Sumitomo Electric Industries Itami Works

Claims (1)

[Scope of utility model registration request] 1. A package for accommodating a square element in which N is an integer of 3 or more, n is an integer of 2 or more, N kinds of power supplies are required, and one power supply has n or more electrodes on each side. In addition, a square substrate 3 having an insulating layer formed on a ceramic or metal plate, sealing glass 4 applied to the outer edges of the four sides of the substrate 3, and a device 1 at the center of the substrate 3 are mounted. A square ceramic frame 20 which is attached to the inner end of the sealing glass 4 on the four sides of the element mounting portion 7
And N number of loop-shaped power source metallized wires 6 provided on the frame 20 and a large number of lead frames 2 whose inner ends are fixed by the sealing glass 4.
A suitable number of outermost lead frames are connected by the N loop-shaped power supply merizing wires 6 and wires 5,
A multi-power-source device package characterized in that n power supply electrodes on each side of the device 1 are connected by a loop-shaped power supply melatized wire 6 and a wire 5 in the immediate vicinity thereof.