JPH11111914A - Three dimensional memory module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of manufacturing processes and shorten TAT by integrally connecting a plurality of semiconductor memory devices via conductive spacers with anisotropic conductive films. SOLUTION: A conductive spacer structure 3 with anisotropic conductive films is made by adhering anisotropic conductive films 1 on both faces of a conductive spacer 2. A semiconductor memory device 6 is a device, wherein a single semiconductor memory device 4 sealed in a case is mounted on one face of a substrate. A plurality of the semiconductor memory devices 6 are located on both faces of the conductive spacer structure 3 with anisotropic conductive films and then pressurized and heated to be connected electrically to form a three dimensional semiconductor memory device 9. A three dimensional memory module 12 is made by mounting a plurality of the three dimensional memory devices 9 provided with solder bumps 10 as external terminals on a memory module substrate 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone / data exchange processing control device and an information processing control device, and more particularly to a storage unit of such a device.

[0002]

2. Description of the Related Art A three-dimensional memory module of this type has conventionally been constituted by three techniques. One is a method of three-dimensionally stacking a plurality of bare semiconductor memory devices flip-chip mounted on a substrate by connecting solder bumps provided on electrodes on the substrate to each other. The other method is to stack a plurality of bare semiconductor memory devices via an insulating film and then form a columnar conductor while dropping conductive epoxy resin between the electrode pads of each chip and connect them to each other. is there. The other is a three-dimensional memory module having a two-story structure in which semiconductor memory chips sealed in a case are mounted on two memory module substrates, and the substrates are connected by an inter-plate connector.

[0003]

First, a plurality of bare semiconductor memory devices flip-chip mounted on a substrate are
The method of connecting the solder bumps provided on the electrodes on the substrate to each other and stacking them three-dimensionally involves manufacturing TAT.
(Turn around time) is long. Next, a method in which a plurality of bare semiconductor memory devices are laminated via an insulating film, and a columnar conductor is formed while the conductive epoxy resin is dropped between the electrode pads of each chip to connect to each other, the columnar method is used. There are drawbacks in that the production yield and cost of the conductor are high. In addition, both are technologies targeting bare chips, and guarantee chips with a known good quality.
e) had a problem. Finally, in a three-dimensional memory module having a two-story structure in which a semiconductor memory chip sealed in a case is mounted on two memory module substrates and the substrates are connected by a board-to-board connector, the shape of the memory module is Therefore, there is a disadvantage that the memory cannot be driven due to an increase in the wiring length, or a large-capacity drive circuit is required.

An object of the present invention is to provide a three-dimensional memory module which can stack semiconductor memory devices at a high density, has a small number of manufacturing steps, has a good yield, and can be stacked three-dimensionally.

[0005]

A three-dimensional memory module according to the present invention comprises an anisotropic conductive film and a plurality of pairs of electrodes electrically connected to each other on the front and back surfaces of a hollow substrate. A conductive spacer structure having an anisotropic conductive film, comprising a conductive spacer, wherein an anisotropic conductive film is adhered to electrodes on the front and back surfaces of the conductive spacer, respectively, and a single semiconductor memory sealed in a case. And a semiconductor memory device having a device mounted on one side of a substrate, wherein a conductive spacer structure is interposed between the two semiconductor memory devices, and the semiconductor memory device is electrically connected by pressing and heating. A three-dimensional semiconductor memory device, comprising:
A two-dimensional memory device is mounted on a memory module substrate via a plurality of connection terminals formed on a bottom surface thereof.

[0006] A semiconductor memory device in which a single semiconductor memory device sealed in a case is mounted on both sides of a substrate can be used, or a semiconductor device in which a single bare semiconductor memory device is mounted on a substrate can be used. A memory device can be used, and a plurality of the above-described three-dimensional memory modules can be stacked three-dimensionally.

According to the present invention, (1) a plurality of semiconductor memory devices are collectively and integrally connected via a conductive spacer with an anisotropic conductive film, so that the number of manufacturing steps is small. (2) In the outer shape of the conductive spacer, since the inside is hollow, semiconductor memory devices can be stacked without any gap in the Z-axis direction. (3) The manufacturing conditions such as heating and pressurizing are relatively loose, and the number of manufacturing steps is small, so that the yield is good. (4) The present invention can be easily applied not only to a bare memory chip but also to a semiconductor memory device sealed in a commercially available case. (5) Since memory chips are three-dimensionally stacked as compared with general SIMM or DIMM type memory modules, a large capacity memory module can be easily realized. In addition, high-density mounting enables driving with a small drive circuit, and power consumption can be reduced.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a rectangular anisotropic conductive film 1 which is a component of the present invention and has a hollow inside. The anisotropic conductive film 1 is a very thin film having a thickness of about 40 μm and a film including conductive particles 101 made of metal particles or plastic particles with a metal film inside an adhesive insulating tape. The inside of the anisotropic conductive film 1 shown in FIG. 1 is hollow and rectangular,
This shape is obtained by arbitrarily selecting and processing a solid or slender tape inside.

FIG. 2 shows a conductive spacer 2 which is a component of the present invention. At the plate end of the conductive spacer 2, a plurality of electrodes 201 that are electrically connected to the front and back surfaces through through holes 202 are arranged and formed. Gold is usually used as the surface material of the electrode. The inside of the conductive spacer 2 in this figure is hollow, which is selected for efficiently stacking semiconductor devices at high density as described later. Can be selected. The material of the conductive spacer 2 is usually an organic substrate, and the plate thickness is 2 mm or less, but can be arbitrarily selected.

FIG. 3 shows a component of the present invention, in which a conductive spacer structure 3 with an anisotropic conductive film 1 is formed by bonding the anisotropic conductive film 1 to both surfaces of the conductive spacer 2.
It is. Since the anisotropic conductive film originally has an adhesive property, the conductive spacer structure 3 with the anisotropic conductive film can be formed by a simple process of simply mounting. At this stage, the anisotropic conductive film 1 does not need to be particularly aligned with the electrodes of the conductive spacer 2.

FIG. 4 shows a semiconductor memory device 6 which is a component of the present invention and in which one semiconductor memory device 4 sealed in a case is mounted on an organic single substrate 5. The single substrate 5 has this name because it is a substrate on which one semiconductor memory device 4 is mounted. Since a single substrate simply mounts only one memory device, an organic substrate having an outer size close to the device size and a two-layer thickness of about 0.4 mm is sufficient. The external electrodes A7 and B8 of the present semiconductor memory device 6 are located at the edge of the single substrate 5 and are electrically connected to both surfaces of the single substrate via through holes 401. The assembly of the semiconductor memory device 6 is performed by a normal reflow soldering device.

FIG. 5 illustrates a process of forming a three-dimensional semiconductor memory device 9 by combining the components of the invention. After a plurality of semiconductor memory devices 6 are positioned on both sides of the conductive spacer structure 3 with an anisotropic conductive film, alignment is performed. The alignment is performed by identifying the recognition mark by the component mounting machine or by using a specific positioning jig. The external electrode pitch of the semiconductor memory device 6 is usually 0.5 mm to 1.27 mm in order to use the case-sealed semiconductor memory device 4. Therefore, the accuracy required for alignment is at most about ± 0.1 mm.

The three-dimensional semiconductor memory device 9 positioned as described above is subjected to pressurization and heating by using a special thermocompression bonding device to apply the pressure to the conductive spacer structure 3 with the anisotropic conductive film.
Are applied in directions opposite to each other from the semiconductor memory devices 6 located on both sides of the semiconductor memory device. The manufacturing conditions at this time are heating at 200 ° C. for 20 seconds and pressurization of 50 g per unit external electrode of the semiconductor memory device 6, for example, 2500 g per side in the case of the semiconductor memory device 4 having 50 terminals. The anisotropically conductive film 1 that has been thermocompression-bonded is crushed by crushing the anisotropically conductive film 1 located on the external electrode of the semiconductor memory device 6 that is opposed to the electrode of the spacer structure 3 with the anisotropically conductive film. The metal particles or metal coated plastic particles inside the film bite into and contact the opposing electrodes, resulting in an electrical connection.

On the other hand, in the portion where there is no electrode facing each other, the anisotropic conductive film 1 is not crushed, or even if crushed, there is no electrode portion into which the conductive particles bite, so that electrical conduction does not occur. FIG. 6 shows the three-dimensional semiconductor memory device 9 manufactured as described above. The electrical conduction part 601 between the semiconductor memory devices is indicated by an arrow in the figure.

FIG. 7 shows a state in which solder bumps 10 are formed on electrodes at the bottom of the three-dimensional semiconductor memory device 9 as external connection terminals. The bump-shaped external terminal has the advantage that a large number of terminals can be provided at a higher density than the lead-shaped terminal, and the connection yield of the solder bump 10 is at least 10 times better than the lead-shaped terminal due to the self-alignment function of the solder. have. The solder bumps 10 can be replaced with connection terminals of other shapes, for example, clip-shaped terminals or brazed pillar-shaped pin-type terminals.

FIG. 8 shows a three-dimensional memory module 1 in which a plurality of three-dimensional semiconductor memory devices 9 having solder bumps 10 as external terminals are mounted on a memory module substrate 11.
2 is shown. It will be apparent that the three-dimensional memory module thus configured can easily realize a memory capacity twice or more that of a normal SIMM or DIMM module.

In this embodiment, the case where semiconductor memory devices are stacked in two stages has been described as an example. However, it goes without saying that it is easy to increase the memory capacity by stacking in more stages. Although the semiconductor memory device 6 is a semiconductor device sealed in a case in the present embodiment, the effect of the present invention is also achieved in a semiconductor memory device 6 configured by flip-chip connection of a bare semiconductor device. It is clear that nothing has changed.

[0018]

As described above, the present invention has the following effects. (1) Since a plurality of semiconductor memory devices are collectively and integrally connected via a conductive spacer with an anisotropic conductive film, the number of manufacturing steps is small and the TAT is fast. (2) In the outer shape of the conductive spacer, since the inside is hollow, the semiconductor memory devices can be stacked without any gap in the Z-axis direction, and there is an effect that the density can be increased. (3) In addition, the manufacturing conditions such as heating and pressurizing are relatively loose, and the number of manufacturing steps is small, so that the yield is good, so that a low-cost memory module can be easily realized. (4) Since the present invention can be easily applied not only to a bare memory chip but also to a semiconductor memory device sealed in a commercially available case, there is an effect of avoiding a cost increase problem due to poor yield related to KGD. . (5) General SIMM (single in memory module)
Alternatively, since memory chips are three-dimensionally stacked as compared with a DIMM (double in memory module) type memory module, there is an effect that a large capacity memory module can be easily realized. (6) The memory drive power can be reduced by high-density mounting, which has the effect of reducing power consumption.

[Brief description of the drawings]

FIG. 1 is a perspective view of an anisotropic conductive film which is one component of the present invention.

FIG. 2 is a perspective view of a conductive spacer which is one component of the present invention.

FIG. 3 is a longitudinal sectional view of a conductive spacer structure with an anisotropic conductive film which is one component of the present invention.

FIG. 4 is a longitudinal sectional view of a semiconductor memory device which is one component of the present invention.

FIG. 5 is an explanatory diagram of a process of forming a three-dimensional semiconductor memory device which is one component of the present invention.

FIG. 6 is a longitudinal sectional view of a three-dimensional semiconductor memory device which is one component of the present invention.

FIG. 7 is an explanatory diagram of a process of forming external connection terminals of a three-dimensional semiconductor memory device which is a component of the present invention.

FIG. 8 is a longitudinal sectional view of the three-dimensional memory module of the present invention.

[Explanation of symbols]

 Reference Signs List 1 anisotropic conductive film 2 conductive spacer 3 conductive spacer structure with anisotropic conductive film 4 semiconductor memory device 5 single substrate 6 semiconductor memory device 7 external electrode A 8 external electrode B 9 three-dimensional semiconductor memory device 10 solder bump 11 memory module Substrate 12 Three-dimensional memory module 101 Conductive particles 201 Electrode 202 Through hole 401 Through hole 601 Conducting part

Claims (5)

[Claims] An anisotropic conductive film (1), and a conductive spacer (2) provided with a plurality of pairs of electrodes electrically connected to each other on both sides of a substrate having a hollow inside, A conductive spacer structure (3) with an anisotropic conductive film formed by bonding the anisotropic conductive film (1) to electrodes on the front and back surfaces of the conductive spacer (2); A semiconductor memory device (6) in which one semiconductor memory device is mounted on one surface of a substrate, wherein the conductive spacer structure (3) is interposed between the two semiconductor memory devices (6). A three-dimensional semiconductor memory device (9) electrically connected to said semiconductor memory device (6) by pressure and heating, wherein said three-dimensional memory device (9) has a plurality of connections formed on a bottom surface thereof; Memory module via terminal Board (11)
A three-dimensional memory module characterized by being mounted thereon. 2. The three-dimensional memory module according to claim 1, comprising a semiconductor memory device in which a single semiconductor memory device sealed in a case is mounted on both sides of a substrate. 3. The three-dimensional memory module according to claim 1, comprising a semiconductor memory device in which a single bare semiconductor memory device is mounted on a substrate. 4. A three-dimensional memory module comprising a plurality of the three-dimensional memory devices according to claim 1 stacked three-dimensionally. 5. An anisotropic conductive film is disposed on both sides of a conductive spacer in which a plurality of pairs of electrodes are electrically connected to each other on both sides of a hollow substrate and disposed on both sides of the substrate. Forming a conductive spacer structure with an anisotropic conductive film; and forming a single semiconductor memory device having a plurality of external electrode pairs on both surfaces of the conductive spacer structure and sealed in a case. Arranging the electrode of the conductive spacer and the external electrode so as to face each other with the anisotropic conductive film interposed therebetween; heating the conductive spacer structure and the semiconductor memory device interposed therebetween; And a step of electrically connecting the semiconductor devices to each other by applying pressure in a direction facing each other from the outside of the semiconductor devices.