Semiconductor memory device and method of fabricating the same

A case for holding a memory device comprising:

• a first cover including a first upper portion, a first lower portion and a first inner wall separating the first upper portion and the first lower portion, the first lower portion including a plurality of ribs on an inner surface of the first cover;
• and
• a second cover including a second upper portion and a second lower portion,
• wherein the first upper portion and the second upper portion are configured to hold the memory device in an inner accommodating room formed by coupling the first cover and the second cover,
• each of the first upper portion and the second upper portion includes a first recessed portion at a first side edge, a contour of the first recessed portion of the first upper portion having a mirror image to that of the first recessed portion of the second upper portion such that the first recessed portion of the first upper portion and the first recessed portion of the second upper portion are coupled to each other, the first recessed portion of the first upper portion being not extended to the first lower portion, the first recessed portion of the second upper portion being not extended to the second lower portion,
• at least one of the first cover and the second cover includes a plurality of openings in at least one corresponding upper portion from among the first upper portion and in the second upper portion, the plurality of openings including a first opening, a second opening, and a third opening, sizes of the first to third openings being different to one another in a width direction, the second and the third openings aligned in a row, while the first opening arranged off-axis from a center of the row in an arrangement direction,
• the case is configured to accommodate only one memory device, and
• the plurality of ribs include a plurality of first-type ribs, the plurality of first-type ribs being perpendicular to the inner wall of the first cover,
• the plurality of first-type ribs are arranged such that distances between two adjacent ones of the plurality of first-type ribs are substantially equal, and
• the plurality of first-type ribs are separate from a bottom edge of the first cover, the bottom edge of the first cover at the first lower portion running substantially parallel with the inner wall, wherein the plurality of first-type ribs are arranged such that a distance between an outermost one of the plurality of first-type ribs and an adjacent side edge of the first cover, the adjacent side edge running parallel with the plurality of first-type ribs, is shorter than a distance between the two adjacent ones of the plurality of first-type ribs.

A semiconductor memory assembly comprising:

• a first cover including a first upper portion, a first lower portion and an inner wall separating the first upper portion and the first lower portion, the first lower portion including a plurality of ribs on an inner surface of the first cover;
• a second cover including a second upper portion and a second lower portion;
• and
• a memory module including a substrate and a semiconductor memory device mounted on the substrate,
• wherein a contour of the first cover has a mirror image to a contour of the second cover such that the first cover and the second cover are coupled to each other to form a case for holding the memory device,
• the first upper portion and the second upper portion defines an accommodating room to hold the memory device therein by the coupling of the first cover to the second cover,
• each of the first upper portion and the second upper portion includes a first recessed portion at a first side edge and a second recessed portion at a second side edge, a contour of the first recessed portion of the first upper portion having a mirror image to that of the first recessed portion of the second upper portion such that the first recessed portion of the first upper portion and the first recessed portion of the second upper portion are coupled to each other, the first recessed portion of the first upper portion being not extended to the first lower portion, the first recessed portion of the second upper portion being not extended to the second lower portion, a contour of the second recessed portion of the first upper portion having a mirror image to that of the second recessed portion of the second upper portion such that the second recessed portion of the first upper portion and the second recessed portion of the second upper portion are coupled to each other, the second recessed portion of the first upper portion being not extended to the first lower portion, the second recessed portion of the second upper portion being not extended to the second lower portion, a size of the first recessed portion being different from a size of the second recessed portion,
• at least one of the first cover and the second cover includes a plurality of openings in at least one corresponding upper portion from among the first upper portion and the second upper portion, the plurality of openings including a first opening, a second opening, and a third opening, sizes of the first to third openings being different to one another in a width direction, the second and the third openings aligned in a row, while the first opening arranged off-axis from a center of the second opening and the third opening in an arrangement direction,
• the accommodating room is configured to accommodate only one memory module,
• the plurality of ribs include a plurality of first-type ribs, the plurality of first-type ribs being substantially perpendicular to the inner wall of the first cover and being connected to the inner wall of the first cover, wherein the plurality of first-type ribs are arranged such that a distance between an outermost one of the plurality of first-type ribs and an adjacent side edge of the first cover, the adjacent side edge running in parallel with the plurality of first-type ribs, is shorter than a distance between two adjacent ones among the plurality of first-type ribs.