JPH04267361A - Leadless chip carrier - Google Patents

Abstract

PURPOSE:To constitute a miniature memory module by connecting the external terminals on the opposite sides of an LCC(leadless chip carrier) thereby stacking a plurality of LCCs. CONSTITUTION:An element mounting part is provided in the center of an insulating substrate 4 having inner terminals 5 arranged around the element mounting part and an insulating substrate 3 having bored part corresponding to the element mounting part is then press bonded to the insulating substrate 4 and integrated therewith. An IC chip 1 is then mounted on the element mounting part of an LCC substrate having an external terminal 9 connected with an inner terminal on the side face and pads 7, 8 arranged on the upper and lower faces of the insulating substrates 3, 4 and connected with the external terminal 9. Electrode of the IC chip 1 and the inner terminal are then bonded with a thin metal wire 2 and only the bored part is sealed with sealing resin 6 thus constituting the LCC. Since the sealing resin 6 does not extend over the top face of the insulating substrate 3, the pads 7, 8 of the external terminal 9 are formed on the opposite faces of the LCC and utilized for interconnection.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leadless chip carrier (hereinafter referred to as LCC).

0002

[Prior Art] As shown in FIG. 3, in a conventional LCC, an IC chip 1 is mounted on an insulating substrate 14 having a recessed part for mounting an element in the center, and an inner part of the insulating substrate 14 is provided with thin metal wires 2. The IC chip 1 is connected to the terminal 5, mounted on the element mounting part of the LCC substrate provided with a resin frame 15 to prevent the sealing resin from flowing onto the insulating substrate 14, and sealed with the sealing resin 6. . Furthermore, external terminals 9 are provided on the side surface of the LCC board and connected to internal terminals 5 to form an LCC.

[0003] When mounting on a motherboard, a soldering pad on the bottom surface of the LCC provided at the external terminal 9 is soldered to a mounting land on the motherboard.

[0004]Although it is possible to form a pad on the top surface of the LCC, since the sealing resin surface is located higher than the pad, it is not possible to connect the LCCs in an overlapping manner.

FIG. 4 is a block diagram showing an example of a memory module using a plurality of memory ICs. IC31～
34 is an address bus 36 and a data bus 35 except for chip select terminals (CS) 37 to 40 taken out individually.
, the circuit is constructed by connecting the power supply terminals in parallel.

[0006]

[Problems to be Solved by the Invention] Conventional LCCs have been mounted flatly on a motherboard, which has led to the problem that the mounting area is large.

[0007]Although it is possible to mount the device on both sides of the motherboard, there is a problem in that the wiring on the motherboard becomes complicated.

[0008]

[Means for Solving the Problems] The LCC of the present invention includes a first insulating substrate provided with an element mounting part in the center and internal terminals arranged around the element mounting part; a second insulating substrate having a corresponding opening and integrated with the first insulating substrate; and an external insulating substrate connected to the internal terminal and provided on the side surfaces of the first and second insulating substrates. terminal and
a pad connected to the external terminal and provided on the lower surface of the first insulating substrate and the upper surface of the second insulating substrate; an IC chip mounted on the element mounting portion and electrically connected to the internal terminal; and a sealing resin that includes the IC chip and seals only the inside of the opening.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention.

As shown in FIG. 1, an insulating substrate 4 has an element mounting part in the center and an internal terminal 5 around the element mounting part, and has an opening corresponding to the element mounting part. 3 are integrated by pressure bonding and are connected to internal terminals on the side surfaces, and external terminals 9 are connected to the external terminals 9 and pads 7 and 8 are provided on the upper and lower surfaces of the insulating substrates 3 and 4. The IC chip 1 is mounted on the IC chip 1, wire bonding is performed between the electrodes of the IC chip 1 and the internal terminals using the metal wires 2, and only the inside of the opening is sealed with the sealing resin 6 to form an LCC.

Since the sealing resin 6 does not exceed the upper surface of the insulating substrate 3, the pads 7 and 8 of the external terminals 9 can be formed on both the upper and lower surfaces of the LCC and used for connection.

Note that if the thickness of the insulating substrate 3 is 0.8 mm and the thickness of the insulating substrate 4 is 0.3 mm, the total thickness of the LCC can be suppressed to a maximum of 1.2 to 1.3 mm. . Since the planar dimensions of a 256 Kbit static RAM memory IC chip are approximately 10 mm x 5 mm, the size of the LCC is approximately 15 mm x 9 mm. L
Compared to the 28 pins of the memory IC chip, the number of CC terminals can be reduced to 4 because the chip select terminals are taken out individually.For example, when configuring 4 memory modules, by adding 3 pins, It is possible to take out the two chip select terminals individually. Therefore, by preparing four types of 31-pin LCCs, an ultra-small memory module can be easily constructed.

FIG. 2 is a schematic cross-sectional view showing the mounting state of the LCC of the present invention.

As shown in FIG. 2, a module in which a plurality of LCCs are stacked and pads 7 and 8 are connected with high temperature solder 10 or conductive adhesive is mounted on a motherboard 11 on an LCC mounting land 12. Mount it on the board and connect it with solder 13.

[0016]

As described above, the present invention has the effect that by making it possible to connect the external terminals of an LCC on both upper and lower sides, a very small memory module can be constructed by stacking a plurality of LCCs.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing the mounting state of the LCC of the present invention.

FIG. 3 is a sectional view showing an example of a conventional LCC.

FIG. 4 is a block diagram showing an example of a memory module that uses a plurality of memory ICs.

[Explanation of symbols]

1 IC chip 2 Fine metal wires 3, 4, 14 Insulating substrate 5 Internal terminal 6 Sealing resin 7, 8 Pad 9 External terminal 10 High temperature solder 11 Motherboard 12 LCC mounting land 13 Solder 15 Resin frame 31, 32, 33, 34 Memory IC ,35
Data bus 36 Address bus

Claims (1)

[Claims] 1. A first insulating substrate having an element mounting part in the center and internal terminals arranged around the element mounting part; and a first insulating substrate having an opening corresponding to the element mounting part. a second insulating substrate provided on and integrated with the first insulating substrate; an external terminal connected to the internal terminal and provided on the side surface of the first and second insulating substrate; and an external terminal connected to the external terminal. Said first
pads provided on the lower surface of the insulating substrate and the upper surface of the second insulating substrate; an IC chip mounted on the element mounting portion and electrically connected to the internal terminal; and only the inside of the opening including the IC chip. A leadless chip carrier characterized by having a sealing resin sealed with.