JP3713034B2 - Memory module - Google Patents

Description

  The present invention relates to an IC mounting technique, and more particularly to a technique that is particularly effective when applied to a semiconductor mounting insulating substrate having a connector terminal array. Related to effective technology.

  In recent years, a memory module in which a plurality of memory ICs are mounted at a high density on an insulating substrate having a connection terminal row on one side has been developed for small electronic devices such as notebook computers. In the conventional plug terminal array in the memory module, the front and back surfaces of the mounting insulating substrate 10 are subjected to copper plating, and then etched to have the same shape of the plug terminals 11a and 11b along one side of the substrate as shown in FIG. ... and 11a ', 11b' ......... are formed on the front and back sides of the substrate, respectively, and a through hole 15 is formed by drilling so as to penetrate the base end of each plug terminal 11 and the substrate. Copper plating was applied from the surface of the plug terminal 11 to the inner surface of the through hole 15 so that the corresponding plug terminals 11 on the front and back of the substrate were electrically connected.

However, the present inventors have revealed that the above-described technique has the following problems.
That is, in the conventional socket mounting type memory module, since the pitch of the plug terminals provided on the mounting insulating substrate is standardized at 2.54 mm or 1.27 mm, the plug can be provided on a certain size of the board. There were restrictions on the number of terminals. In other words, there has been a problem that, when trying to secure the necessary number of plug terminals, the outer dimensions of the substrate are limited by the number of plug terminals.

SUMMARY OF THE INVENTION An object of the present invention is to provide a module using a substrate having a structure in which a double number of plug terminals can be provided on an insulating substrate having the same size as the conventional one without changing the pitch. Alternatively, an object of the present invention is to provide a substrate structure in which the size of an insulating substrate can be approximately halved if the number of connecting terminals is the same, and a module using the substrate having such a structure.
The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

Outlines of representative ones of the inventions disclosed in the present application will be described as follows.
That is, the plug terminals provided on the front and back of the insulating substrate are formed to be separate plug terminals that are electrically insulated from each other.
Specifically, a rectangular insulating substrate having first and third sides facing each other and second and fourth sides facing each other, and a surface of the insulating substrate along the first side A plurality of semiconductor terminals including a plurality of plug terminals electrically insulated from each other on the side and the back side, a plurality of memories provided on the insulating substrate, and a driver for transmitting a common signal to the plurality of memories The semiconductor mounting apparatus includes a device and a wiring provided on the insulating substrate and electrically connecting the semiconductor device and the plug terminal.

  According to the above means, it is possible to provide twice the number of plug terminals without changing the pitch on the same size insulating substrate as before, or if the number of plug terminals is the same, The size can be halved.

  Further, in the insulating substrate, it is preferable that notches for preventing erroneous insertion are provided on the first side, and notches for retaining are respectively provided on the second and fourth sides. As a result, it is possible to prevent erroneous insertion when the insulating substrate is mounted on the socket, and to prevent the substrate from coming off after the substrate is mounted.

  Also, a rectangular insulating substrate, a plurality of plug terminals provided on both surfaces of the insulating substrate along one long side of the insulating substrate, and a plurality of plug terminals provided on the insulating substrate And a wiring board that is provided on the insulating substrate and electrically connects the semiconductor device and the plug terminal, and the plug terminal includes a terminal for identifying the substrate. Good. This makes it possible to standardize substrates for a plurality of types of modules with different specifications, thereby reducing the total cost.

  Further, also in the case of the insulating substrate, it is preferable to provide a notch for preventing erroneous insertion on the long side of the insulating substrate, and a notch for preventing the slipping on the two short sides of the insulating substrate. Accordingly, it is possible to prevent erroneous insertion when the insulating substrate is attached to the socket, and it is possible to prevent the substrate from being detached after the substrate is attached.

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
That is, it is possible to provide twice the number of conventional plug terminals on the insulating substrate on which the IC is mounted without changing the pitch, or if the number of plug terminals is the same, the size of the insulating substrate is approximately the same. Can be halved.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

  1 to 3 show an embodiment of a memory module to which the present invention is applied. In the memory module of this embodiment, eight memory ICs 20 and one driver IC 30 are mounted on the front and back surfaces of the insulating substrate 10 respectively, and the same shape is formed on the front and back of the insulating substrate 10 along one side of the substrate. Are formed at an equal pitch P. The plug terminals 11a, 11b, 11c,. The front-side plug terminals 11a, 11b, 11c,... Of the insulating substrate 10 and the back-side plug terminals 11a ', 11b', 11c ', ... are electrically insulated from each other. Moreover, in this embodiment, although not particularly limited, the front side plug terminals 11a, 11b, 11c,... And the back side plug terminals 11a ′, 11b ′, 11c ′,. As shown in FIG. 2, the positions are shifted from each other by a half pitch P / 2.

  The insulating substrate 10 has a multilayer structure in which a plurality of (for example, six) insulating substrates each having a wiring pattern formed of a conductive layer on the surface are laminated. In this embodiment, as the material of the insulating substrate 10, a high TG material (glass with a high softening temperature) called FR-5 having a thermal expansion coefficient of about 10 ppm is used. As a result, the memory IC 20 having a TSOP (thin small outline package) structure can be mounted.

  That is, since the thermal expansion coefficient of a substrate made of glass epoxy or the like called FR-4, which has been generally used in the past, is about 16 ppm, the thermal expansion coefficient of the solder joint is about 5 ppm. If a memory IC with a thin small outline package) structure is used, the solder joint may peel off due to thermal cycling, etc., so a memory IC with an SOJ structure with a solder joint thermal expansion coefficient of about 10 ppm is mounted. I had to do it.

  However, in this embodiment, since a high TG material having a thermal expansion coefficient of about 10 ppm is used as the material of the substrate 10, the TSOP having a thermal expansion coefficient of about 5 ppm bent so that the lead terminal expands to the outside is used. A memory IC having a thin small outline package) structure can be used. As a result, the height of the IC when mounted on the substrate is lowered, and the module can be miniaturized.

  Furthermore, in this embodiment, a memory IC 20 in which lead terminals are bent in opposite directions is soldered to a predetermined position of the insulating substrate 10. That is, the memory IC 20 mounted on the front side of the insulating substrate 10 has the lead terminals 21 bent toward the antinode side of the IC, as shown in FIG. 3, and the memory IC 20 mounted on the back side of the insulating substrate 10. The lead terminal 21 'is bent toward the back side of the IC. As a result, the signal terminals of the IC on the front surface and the IC on the back surface come to the same position, so that it is possible to share the wiring pattern to be formed on the surface of the substrate 10 and to easily form the wiring with the shortest distance. Become. Therefore, the design of the wiring pattern is facilitated, the number of intersections between the wirings can be reduced, the wiring is simplified, and the characteristics and quality of the module are improved.

  As shown in FIG. 1, notches 12a, 12b and 13a, 13b are respectively formed on the side of the insulating substrate 10 where the plug terminal 11 is formed and on two sides orthogonal thereto. Of these, notches 12a and 12b on the side where the contact terminal is formed are mechanical key-in notches (recesses) for preventing erroneous insertion, and 13a and 13b are notches for retaining.

  That is, the insulating substrate 10 of this embodiment has a suitable structure to be mounted on the socket 40 as shown in FIG.

Next, an embodiment of the socket 40 will be described.
The socket 40 to which the insulating substrate 10 is attached is a terminal corresponding to the number of the plug terminals 11a, 11b, 11c... And 11a, 11b, 11c... And 11a ′, 11b ′, 11c ′. Pins 41a, 41b, 41c,... Are provided on the outer side, and projections 42a, 42b that can be engaged with the notches are provided on the inner side at positions corresponding to the notches 12a, 12b.

  Each of the terminal pins 41a, 41b, 41c,... Is integrally formed with a lead 43 made of an elastic piece that can come into contact with each of the plug terminals 11, as shown in FIG. Is held in the socket housing 44 at a pitch P / 2 which is half the pitch P of the plug terminal. The leads 43 are spaced apart from each other, and the lead 43 has a slightly downward lead as shown by a solid line A and a slightly upward lead as shown by a two-dot chain line B in FIG. By disposing, the engaging portions are opposed to each other with a slightly narrower distance from the thickness of the substrate 10. The insulating substrate 10 is mounted by inserting the plug terminal portion into the engaging portion constituted by the lead 43 from the direction of arrow C and rotating it in the direction of arrow D.

  As shown in FIG. 4, a pair of holding arms 45a and 45b having protrusions 47a and 47b at the tip end portions are attached to both ends of the socket 40 so as to be rotatable about the pins 46a and 46b. After attaching the insulating substrate 10 to the substrate 10, the holding arms 45 a and 45 b are rotated inward, and the protrusions 47 a and 47 b are engaged with the notches 13 a and 13 b on the side surface of the substrate 10, thereby preventing the substrate from coming off. It has become so.

  Furthermore, operating pieces 48a and 48b are formed inwardly on the holding arms 45a and 45b, and the operating pieces 48a and 48b are mounted when the pins 46a and 46b are rotated outward with the pins 46a and 46b as fulcrums, respectively. The substrate 10 is pushed out and separated. As a result, the connection between the board 10 and the socket 40, which has become difficult to remove due to an increase in the terminal density, can be easily removed based on this principle by operating the holding arms 45a and 45b.

  Further, the insulating substrate 10 of this embodiment includes substrate identification PD terminals 17a, 17b, 17c and 17d, jumper chip connection terminals 18a, 18b, 18c and 18d, and ground terminals (or Vcc terminals) 19a and 19b. , 19c, 19d on the surface of the substrate, and a wiring pattern 50 for connecting the PD terminals 17a, 17b, 17c, 17d to the jumper chip connection terminals 18a, 18b, 18c, 18d is shown by broken lines in FIG. A conductor (0Ω resistance) for short-circuiting between the PD terminals 17a, 17b, 17c, 17d and the ground terminals (or Vcc terminals) 19a, 19b, 19c, 19d. Jumper chips 50a, 50c,. The jumper chips 50a, 50c,... Are used to generate codes for identifying modules having different specifications.

  That is, as shown in FIG. 6, the PD terminals 17a and 17c to which the jumper chips 50a and 50c are connected are fixed to the ground potential (or Vcc potential), and the PD terminals 17b and 17d to which the jumper chips are not connected are NC terminals (noon). A connection terminal), the microprocessor reads the state of the PD terminals 17a to 17d to determine what type of module it is, that is, the table of its own storage capacity and electrical characteristics, for example. This can be known by referring to (memory). If there are four PD terminals, 16 types of modules can be identified, and if n, 2 n types of modules can be identified.

  FIG. 7 shows a block configuration example of the memory module. The module of this embodiment is composed of 16 dynamic RAMs D0 to D15 (memory IC 20) and drivers B0 to B26. Each of the drivers B0 to B26 is formed on one semiconductor chip by half and formed into an IC, and mounted on the substrate 10 (IC30 in FIG. 1). The drivers B0 to B26 are used to transmit signals (OE, WE, CAS, etc.) common to a plurality of dynamic RAMs to each chip.

  As described above, since the driver is provided on the module side, a driver on the CPU side that drives the driver is unnecessary, and the user does not need to design a driver for each type of module. In other words, if there is no driver on the module side, the driving force required to drive the module changes when the module to be used changes. Therefore, it is necessary to redesign the optimum driver. Since it is provided on the module side, a driver on the CPU side becomes unnecessary.

  As described above, in the above embodiment, the plug terminals provided on the front and back of the insulating substrate are formed so as to be separate plug terminals that are electrically insulated from each other. It is possible to provide twice as many plug terminals on the insulating substrate without changing the pitch. Alternatively, if the number of plug terminals is the same, there is an effect that the size of the insulating substrate can be halved.

  In addition, a low thermal expansion material was used as the insulating substrate material, and it was mounted as an IC with a TSOP (thin small outline package) structure, so it was mounted on an insulating substrate compared to an SOJ structure IC. There is an effect that the module is miniaturized by reducing the height of the IC in the state.

  In addition, since the plug terminal row on the front surface side and the plug terminal row on the back surface side of the insulating substrate are formed so as to be shifted from each other by a half pitch, leads (connectors) that come into contact with the respective plug terminal rows are formed. There is an effect that it is easy to make a socket having.

  Furthermore, since a notch is provided on the end surface of the insulating substrate on the side of the terminal block, and a protrusion that can be engaged with the notch is provided at a corresponding position of the socket, the system is inserted into an incorrect substrate (module). Can be prevented from malfunctioning, and the IC in the module can be prevented from being damaged.

  In addition, a plurality of board identification terminals (PD terminals) are provided in a part of the plug terminal array of the insulating board, and a jumper chip for selectively short-circuiting between these terminals and the power supply terminals can be mounted. Since the terminals are provided, it is possible to standardize the board for a plurality of types of modules having different specifications, and to reduce the total cost.

  The invention made by the present inventor has been specifically described on the basis of the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Nor. For example, in the above embodiment, a plurality of memory ICs are mounted on the front and back surfaces of the insulating substrate, respectively, but a plurality of ICs may be mounted only on one of the front and back surfaces of the insulating substrate.

  In the above description, the case where the invention made mainly by the present inventor is applied to the memory module which is the field of use as the background has been described. However, the present invention is not limited to this, and the memory card or other single insulation is used. It can be widely used for a semiconductor mounting substrate in which a plurality of ICs are mounted on a substrate.

It is a top view which shows one Example of the memory module to which this invention is applied. FIG. 2 is an enlarged explanatory view of a plug terminal portion of the memory module of FIG. 1. FIG. 2 is an enlarged explanatory view showing an IC mounting state of the memory module of FIG. 1. FIG. 3 is a side view showing an embodiment of a socket in which the memory module of FIG. 1 is mounted. It is an expanded sectional view which shows the structure of the socket of FIG. It is an equalization circuit diagram which shows the relationship between PD terminal and a jumper chip. FIG. 2 is a block diagram illustrating a configuration example of a memory module in FIG. 1. It is an expansion explanatory view of the connection terminal part of the conventional memory module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Insulation board | substrate 11a, 11b, 11c Plug terminal 12a, 12b Notch 13a, 13b for mechanical key-in Notch 17a-17d for retaining prevention PD terminal 20 Memory IC
30 Driver IC
40 Socket 50a, 50c Jumper chip

Claims (2)

A rectangular insulating substrate having first and third sides facing each other and second and fourth sides facing each other;
A plurality of plug terminals provided to be electrically insulated from each other on the front side and the back side of the insulating substrate along the first side;
A plurality of semiconductor devices including a plurality of memory ICs provided on the front surface and the back surface of the insulating substrate , respectively, and a driver IC that transmits a common signal to the plurality of memory ICs;
A mechanical key-in notch for preventing erroneous insertion provided in the approximate center of the first side of the insulating substrate ;
Corresponding external terminals of the memory IC provided on the surface of the insulating substrate and the memory IC provided on the back surface of the insulating substrate are connected to the surface of the insulating substrate via a common wiring pattern formed on the insulating substrate. A memory module characterized by being connected to any one of the plug terminals on the side or back side . The insulating substrate includes notches for preventing erroneous insertion provided on the first side and retaining notches provided on the second and fourth sides, respectively. The memory module according to claim 1.

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