DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0084] Hereunder, a semiconductor device and a semiconductor module in accordance with embodiments of the present invention will be described by using a chip size package and a ball grid array as examples.

[0085] FIG. 1 ( a ) schematically shows a plan view of the structure of a ball grid array in accordance with a first embodiment of the present invention, and FIG. 1 ( b ) shows a cross-sectional view taken along lines A-A of FIG. 1 ( a ).

[0086] Referring to FIG. 1 , wirings 2 a and 2 c are formed on both surfaces of an interposer substrate 1 , respectively, and the wirings 2 a and 2 c formed on the respective surfaces are connected to one another via through hole wirings 2 b that are formed in the interposer substrate 1 .

[0087] Further, a semiconductor chip 3 is mounted on a front surface of the interposer substrate 1 , and the semiconductor chip 3 is connected to the wirings 2 a through the bump electrodes 4 , and sealed with mold resin 5 .

[0088] Also, for example, solder balls 6 as terminal electrodes are disposed on a back surface of the interposer substrate 1 , and the solder balls 6 are connected to the wirings 2 c . Here, the solder balls 6 are disposed in a manner to avoid diagonal lines 7 of the interposer substrate 1 ′.

[0089] As a result, the solder balls 6 can be prevented from being disposed in regions where stresses that work on the interposer substrate 1 are large, and the connection reliability of the solder balls 6 can be improved by merely adjusting the disposing positions of the solder balls 6 .

[0090] For this reason, even when the ball grid array becomes to be a large size, the connection reliability of the solder balls 6 can be improved without complicating the structure of the ball grid array, and the reliability in the secondary mounting of the ball grid array can be improved while restricting an increase in the cost.

[0091] As the interposer substrate 1 , for example, a silicon substrate, a ceramics substrate, a glass epoxy substrate, or a build-up multi-layered substrate can be used. Also, as the terminal electrodes provided on the back surface of the interposer substrate 1 , for example, Au bump electrodes, or bump electrodes composed of Ni bumps covered with Au films or solder films may be used, besides the solder balls 6 .

[0092] FIG. 2 ( a ) schematically shows a plan view of the structure of a ball grid array in accordance with a second embodiment of the present invention, and FIG. 2 ( b ) shows a cross-sectional view taken along lines B-B of FIG. 2 ( a ).

[0093] In FIG. 2 , wirings 12 a and 12 c are formed on both surfaces of an interposer substrate 11 , respectively, and the wirings 12 a and 12 c formed on the respective surfaces are connected to one another via through hole wirings 12 b that are formed in the interposer substrate 11 .

[0094] Further, a semiconductor chip 13 is mounted on a front surface of the interposer substrate 11 , and the semiconductor chip 13 is connected to the wirings 12 a through bump electrodes 14 , and sealed with mold resin 15 .

[0095] Also, for example, solder balls 16 as terminal electrodes are disposed on a back surface of the interposer substrate 11 , and the solder balls 16 are connected to the wirings 12 c . Here, the solder balls 16 are disposed in a manner to avoid diagonal lines of the interposer substrate 11 , and grooves 17 are formed along the diagonal lines in the interposer substrate 11 .

[0096] For this reason, stresses that work on the interposer substrate 11 can be segmented, to thereby lower the stresses applied to the interposer substrate 11 can be lowered and; even when the size of the interposer substrate 11 is enlarged, warps of the interposer substrate 11 can be reduced, and the reliability in the secondary mounting can be improved.

[0097] It is noted that, in the embodiment described above, a method in which the grooves 17 are provided along the diagonal lines of the interposer substrate 11 is described. However, holes or slits may be provided instead of the grooves 17 . Also, grooves and holes or slits may be mixed and provided.

[0098] FIG. 3 ( a ) schematically shows a plan view of the structure of a ball grid array in accordance with a third embodiment of the present invention, and FIG. 3 ( b ) shows a cross-sectional view taken along lines C-C of FIG. 3 ( a ).

[0099] In FIG. 3 , wirings 22 a are formed on a front surface of an interposer substrate 21 , and wirings 22 c and dummy lands 22 d having dummy balls 28 disposed thereon are formed on a back surface of the interposer substrate 21 . The wirings 22 a and 22 c formed on the respective surfaces are connected to one another via through hole wirings 22 b that are formed in the interposer substrate 21 .

[0100] Further, a semiconductor chip 23 is mounted on the front surface of the interposer substrate 21 , and the semiconductor chip 23 is connected to the wirings 22 a through bump electrodes 24 , and sealed with mold resin 25 .

[0101] Also, for example, solder balls 26 and dummy balls 28 respectively as terminal electrodes and dummy terminals are disposed on the back surface of the interposer substrate 21 , and the solder balls 26 are connected to the wirings 22 c , and the dummy balls 28 are disposed on the dummy lands 22 d.

[0102] Here, the solder balls 26 are disposed in a manner to avoid diagonal lines of the interposer substrate 21 , and the dummy balls 28 are disposed at predetermined intervals on the diagonal lines 27 of the interposer substrate 21 .

[0103] As a result, the solder balls 26 are prevented from being disposed on the diagonal lines 27 where large stresses are generated, and the dummy balls 28 can be disposed in regions where the solder balls 26 are not disposed, such that the connection state of the solder balls 26 can be reinforced by the dummy balls 28 .

[0104] For this reason, even when the size of the interposer substrate 21 is enlarged, stresses that work on the interposer substrate 21 can be lowered, and poor connections of the solder balls 26 can be reduced, and the reliability in the secondary mounting can be readily improved.

[0105] It is noted that the solder balls 26 and the dummy balls 28 may be made of the same material and in the same size and shape. However, the solder balls 26 and the dummy balls 28 may be made of different material and in different sizes and shapes.

[0106] When the solder balls 26 and the dummy balls 28 are made of the same material and in the same size and shape, the solder balls 26 and the dummy balls 28 can be collectively formed, which prevents the manufacturing process from becoming complex.

[0107] On the other hand, when the solder balls 26 and the dummy balls 28 are made of different material, the solder balls 26 and the dummy balls 28 can have different bonding forces. Therefore even when the dummy balls 28 are disposed on the diagonal line 27 , the dummy balls 28 are difficult to come off, and poor connections of the solder balls 26 can be reduced.

[0108] For example, the dummy balls 28 can be composed of resin balls covered with solder.

[0109] By this, flexible deformation can readily occur in the dummy balls 28 , such that the dummy balls 28 become difficult to come off even when deforming stresses work on the dummy balls 28 . Accordingly, poor connections of the dummy balls 28 can be reduced, and poor connections of the solder balls 26 can be reduced.

[0110] Also, as the dummy balls 28 are covered with solder, the dummy balls 28 can be flexibly deformed, and the solder balls 26 and the dummy balls 28 can be collectively connected, and therefore the manufacturing process is prevented from becoming complex.

[0111] FIG. 4 ( a ) schematically shows a plan view of the structure of a ball grid array in accordance with a fourth embodiment of the present invention, and FIG. 4 ( b ) shows a cross-sectional view taken along lines C′-C′ of FIG. 4 ( a ).

[0112] In FIG. 4 , wirings 122 a are formed on a front surface of an interposer substrate 121 , and wirings 122 c and dummy lands 122 d having dummy balls 128 disposed thereon are formed on a back surface of the interposer substrate 121 . The wirings 122 a and 122 c formed on the respective surfaces are connected to one another via through hole wirings 122 b that are formed in the interposer substrate 121 .

[0113] Further, a semiconductor chip 123 is mounted on the front surface of the interposer substrate 121 , and the semiconductor chip 123 is connected to the wirings 122 a through bump electrodes 124 , and sealed with mold resin 125 .

[0114] Also, for example, solder balls 126 and dummy balls 128 as terminal electrodes and dummy terminals are disposed on the back surface of the interposer substrate 121 , and the solder balls 126 are connected to the wirings 122 c , and the dummy balls 128 are disposed on the dummy lands 122 d.

[0115] Here, the solder balls 126 are disposed in a manner to avoid diagonal lines 127 of the interposer substrate 121 , and the dummy balls 128 are continuously disposed on the diagonal lines 127 of the interposer substrate 121 so that they are in contact with one another.

[0116] As a result, the solder balls 126 are prevented from being disposed on the diagonal lines 127 where large stresses are generated, and the connection state of the solder balls 126 can be reinforced by the dummy balls 128 , and the bonding force by the dummy balls 128 can be readily increased without changing the size of the dummy balls 128 .

[0117] For this reason, the bonding force by the dummy balls 128 can be increased, and the solder balls 126 and the dummy balls 128 can be collectively formed and collectively connected, and stresses that are generated in the interposer substrate 121 can be effectively absorbed without complicating the manufacturing process.

[0118] FIG. 5 ( a ) schematically shows a plan view of the structure of a ball grid array in accordance with a fifth embodiment of the present invention, FIG. 5 ( b ) shows a cross-sectional view taken along lines D 1 -D 1 of FIG. 5 ( a ), and FIG. 5 ( c ) shows a cross-sectional view taken along lines D 2 -D 2 of FIG. 5 ( a ).

[0119] Referring to FIG. 5 , wirings 32 a are formed on a front surface of an interposer substrate 31 , and wirings 32 c and dummy lands 32 d having dummy balls 38 disposed thereon are formed on a back surface of the interposer substrate 31 . The wirings 32 a and 32 c formed on the respective surfaces are connected to one another via through hole wirings 32 b that are formed in the interposer substrate 31 .

[0120] Further, a semiconductor chip 33 is mounted on the front surface of the interposer substrate 31 , and the semiconductor chip 33 is connected to the wirings 32 a through bump electrodes 34 , and sealed with mold resin 35 .

[0121] Also, for example, solder balls 36 and dummy balls 38 respectively as terminal electrodes and dummy terminals are disposed on the back surface of the interposer substrate 31 , and the solder balls 36 are connected to the wirings 32 c , and the dummy balls 38 are disposed on the dummy lands 32 d.

[0122] Here, the solder balls 36 are disposed inside the interposer substrate 31 in a manner to avoid diagonal lines 37 of the interposer substrate 31 , and the dummy balls 38 are disposed in the four corners at the outermost circumference of the interposer substrate 31 .

[0123] Accordingly, the solder balls 36 are prevented from being disposed in regions where large stresses are generated, and the stresses generated in the interposer substrate 31 can be effectively absorbed by the dummy balls 38 , and the reliability in the secondary mounting can be readily improved.

[0124] FIG. 6 ( a ) schematically shows a plan view of the structure of a ball grid array in accordance with a sixth embodiment of the present invention, FIG. 6 ( b ) shows a cross-sectional view taken along lines E 1 -E 1 of FIG. 6 ( a ), and FIG. 6 ( c ) shows a cross-sectional view taken along lines E 2 -E 2 of FIG. 6 ( a ).

[0125] Referring to FIG. 6 , wirings 42 a are formed on a front surface of an interposer substrate 41 , and wirings 42 c and dummy lands 42 d having dummy balls 48 a - 48 c disposed thereon are formed on a back surface of the interposer substrate 41 . The wirings 42 a and 42 c formed on the respective surfaces are connected to one another via through hole wirings 42 b that are formed in the interposer substrate 41 .

[0126] Further, a semiconductor chip 43 is mounted on the front surface of the interposer substrate 41 , and the semiconductor chip 43 is connected to the wirings 42 a through bump electrodes 44 , and sealed with mold resin 45 .

[0127] Also, for example, solder balls 46 and dummy balls 48 respectively as terminal electrodes and dummy terminals are disposed on the back surface of the interposer substrate 41 , and the solder balls 46 are connected to the wirings 42 c , and the dummy balls 48 are disposed on the dummy lands 42 d.

[0128] Here, the solder balls 46 are disposed inside the interposer substrate 41 in a manner to avoid diagonal lines 47 of the interposer substrate 41 , and the dummy balls 48 a - 48 c are disposed in contact with one another in each of the four corners of the interposer substrate 41 .

[0129] By this, the bonding force by the dummy balls 48 a - 48 c can be increased by merely adjusting the disposing positions of the dummy balls 48 a - 48 c , and the size of the dummy balls 48 a - 48 c does not need to be changed for increasing the bonding force by the dummy balls 48 a - 48 c.

[0130] For this reason, the solder balls 46 and the dummy balls 48 a - 48 c can be collectively formed and collectively connected, and stresses that are generated in the interposer substrate 41 can be effectively absorbed without complicating the manufacturing process.

[0131] FIG. 7 ( a ) schematically shows a plan view of the structure of a chip size package in accordance with a seventh embodiment of the present invention, and FIG. 7 ( b ) shows a cross-sectional view taken along lines F-F of FIG. 7 ( a ).

[0132] Referring to FIG. 7 , a wiring layer 52 connected to an active region is formed on a semiconductor chip 51 , and pad electrodes 53 are formed on the wiring layer 52 . Also, a stress buffer layer 54 is formed on the active region that is formed on the semiconductor chip 51 in a manner to expose the pad electrodes 53 . Rearrangement wirings 55 extending over the stress buffer layer 54 are formed on the pad electrodes 53 .

[0133] Here, the rearrangement wiring 55 can be composed of, for example, a three-layer structure including a TiW-sputtered wiring layer, a Cu-sputtered wiring layer and a Cu-plated wiring layer.

[0134] Also, a protection layer, such as, for example, a solder resist film 56 is formed on the rearrangement wirings 55 , and opening sections 57 that expose the rearrangement wirings 55 over the stress buffer layer 54 are formed in the solder resist film 56 .

[0135] Furthermore, as bump electrodes, for example, solder balls 58 are disposed on the stress buffer layer 54 , and the solder balls 58 are connected to the rearrangement wirings 55 via the opening sections 57 formed in the solder resist film 56 . Here, the solder balls 58 are disposed in a manner to avoid diagonal lines 59 of the semiconductor chip 51 .

[0136] By this, the solder balls 58 can be disposed while avoiding regions where stresses working on the semiconductor chip 51 are large, and the connection reliability of the solder balls 58 can be improved by merely adjusting the disposing position of the solder balls 58 .

[0137] For this reason, even when the chip size package becomes large, poor connections of the solder balls 58 can be reduced without complicating the structure of the chip size package, an increase in the cost can be restricted, and the reliability in the secondary mounting of the chip size package can be improved.

[0138] It is noted that, as the bump electrodes provided on the stress buffer layer 54 , for example, Au bump electrodes, or bump electrodes composed of Ni bumps covered with Au films or solder films may be used, besides the solder balls 58 .

[0139] FIG. 8 ( a ) schematically shows a plan view of the structure of a chip size package in accordance with an eighth embodiment of the present invention, and FIG. 7 ( b ) shows a cross-sectional view taken along lines G-G of FIG. 8 ( a ).

[0140] Referring to FIG. 8 , a wiring layer 62 connected to an active region is formed on a semiconductor chip 61 , and pad electrodes 63 are formed on the wiring layer 62 . Also, a stress buffer layer 64 is formed on the active region that is formed on the semiconductor chip 61 in a manner to expose the pad electrodes 63 . Dummy lands 65 b having dummy balls 68 b disposed thereon are provided on the stress buffer layer 64 , and rearrangement wirings 65 a extending over the stress buffer layer 64 are formed on the pad electrodes 63 .

[0141] Here, the rearrangement wiring 65 a and the dummy lands 65 b can be composed of, for example, a three-layer structure including a TiW-sputtered wiring layer, a Cu-sputtered wiring layer and a Cu-plated wiring layer.

[0142] Also, as a protection layer, for example, a solder resist film 66 is formed on the rearrangement wirings 65 a and the dummy lands 65 b , and opening sections 67 a and 67 b that expose the rearrangement wirings 65 a and the dummy lands 65 b , respectively, over the stress buffer layer 64 are formed in the solder resist film 66 .

[0143] Furthermore, as bump electrodes and dummy bumps, for example, solder balls 68 a and dummy balls 68 b are disposed on the stress buffer layer 64 . The solder balls 68 a are connected to the rearrangement wirings 65 via the opening sections 67 a formed in the solder resist film 66 , and the dummy balls 68 b are disposed on the dummy lands 65 b through the opening sections 67 b formed in the solder resist film 66 .

[0144] Here, the solder balls 68 a are disposed in a manner to avoid diagonal lines 69 of the semiconductor chip 61 , and the dummy balls 68 b are disposed at predetermined intervals on the diagonal lines 69 of the semiconductor chip 61 .

[0145] As a result, the solder balls 68 a are prevented from being disposed on the diagonal lines 69 where large stresses are generated, and the connection state of the solder balls 68 a can be reinforced by the dummy balls 68 b.

[0146] For this reason, even when the size of the semiconductor chip 61 is large, stresses that work on the semiconductor chip 61 can be lowered, and poor connections of the solder balls 68 a can be reduced, and the reliability in the secondary mounting can be readily improved.

[0147] It is noted that the solder balls 68 a and the dummy balls 68 b may be made of the same material and in the same size and shape. However, the solder balls 68 a and the dummy balls 68 b may be made of different material and in different sizes and shapes.

[0148] FIG. 9 ( a ) schematically shows a plan view of the structure of a chip size package in accordance with a ninth embodiment of the present invention, and FIG. 9 ( b ) shows a cross-sectional view taken along lines H-H of FIG. 9 ( a ).

[0149] Referring to FIG. 9 , a wiring layer 72 connected to an active region is formed on a semiconductor chip 71 , and pad electrodes 73 are formed on the wiring layer 72 .

[0150] Further, stress buffer layers 74 a - 74 b formed in a manner to expose the pad electrodes 73 are divided and disposed on an active region of the semiconductor chip 71 , and rearrangement wirings 75 that extend over the stress buffer layers 74 a - 74 b are formed on the pad electrodes 73 .

[0151] Here, the rearrangement wiring 75 can be composed of, for example, a three-layer structure including a TiW-sputtered wiring layer, a Cu-sputtered wiring layer and a Cu-plated wiring layer.

[0152] Also, solder resist films 76 a - 76 d that are divided and disposed at places corresponding to the respective stress buffer layers 74 a - 74 d are formed on the rearrangement wirings 75 and the pad electrodes 73 . Opening sections 77 that expose the rearrangement wirings 75 over the respective stress buffer layers 74 a - 74 d are formed in the solder resist films 76 a - 76 d.

[0153] As bump electrodes, for example, solder balls 78 are formed on the respective stress buffer layers 74 a - 74 d , and the respective solder balls 78 are connected to the rearrangement wirings 75 via the opening sections 77 formed in the respective solder resist films 76 a - 76 d.

[0154] Here, the solder balls 78 are disposed in a manner to avoid diagonal lines of the semiconductor chip 71 , and the stress buffer layers 74 a - 74 d and the solder resist films 76 a - 76 d are divided along the diagonal lines of the semiconductor chip 71 .

[0155] By this, stresses that work on the semiconductor chip 71 can be segmented, thereby lowering the stresses that work on the semiconductor chip 71 . Therefore warps of the semiconductor chip 71 can be reduced, and the reliability in the secondary mounting can be improved even when the size of the semiconductor chip 71 is large.

[0156] FIG. 10 are cross-sectional views illustrating a method for manufacturing a chip size package in accordance with a tenth embodiment of the present invention.

[0157] As shown in FIG. 10 ( a ), a wiring layer 72 having pad electrodes 73 provided thereon is formed on a semiconductor wafer W.

[0158] Then, as shown in FIG. 10 ( b ), a resin film such as polyimide film is coated on the semiconductor wafer W where the wiring layer 72 and the pad electrodes 73 are formed; and the resin film is patterned by using photolithography technique to thereby expose the pad electrodes 73 , and form stress buffer layers 74 a - 74 d on the wiring layer 72 , which are divided along the diagonal lines.

[0159] Next, as shown in FIG. 10 ( c ), over the semiconductor wafer W having the stress buffer layers 74 a - 74 d formed thereon, a TiW-sputtered film and a Cu-sputtered film are successively deposited in layers by sputtering, and then a plating resist film is coated.

[0160] Then, by using photolithography technique, opening sections corresponding to rearrangement wirings 75 are formed in the plated resist film, and Cu-plated wiring layers are formed through the opening sections by conducting electrolytic copper plating.

[0161] Then, the plated resist film is removed, and the Cu-sputtered film and the TiW-sputtered film are successively etched using the Cu-plated wiring layers as masks, to thereby form Cu-sputtered wiring layers and TiW-sputtered wiring layers, thereby completing the rearrangement wirings 75 .

[0162] Next, as shown in FIG. 10 ( d ), solder resist is coated on the rearrangement wirings 75 ; and by using photolithography technique, solder resist films 76 a - 76 d that are divided and disposed along the diagonal lines are formed on the rearrangement wirings 75 , and opening sections 77 that expose the rearrangement wirings 75 are formed in the solder resist films 76 a - 76 d.

[0163] Then, as shown in FIG. 10 ( e ), solder balls 78 that are connected via the opening sections 77 to the rearrangement wirings 75 are formed on the solder resist films 76 a - 76 d . Reinforcing resin is coated over the entire surface depending on the necessity, and then the solder balls 78 are exposed by sputtering to thereby reinforce base sections of the solder balls 78 .

[0164] By this, when the stress buffer layers 74 a - 74 d and the solder resist films 76 a - 76 d are patterned, the stress buffer layers 74 a - 74 d and the solder resist films 76 a - 76 d can be divided, and thus stresses that work on the semiconductor chip 71 can be segmented without increasing the number of manufacturing steps.

[0165] FIG. 11 ( a ) schematically shows a plan view of the structure of a chip size package in accordance with an eleventh embodiment of the present invention, FIG. 11 ( b ) shows a cross-sectional view taken along lines I 1 -I 1 of FIG. 11 ( a ), and FIG. 11 ( c ) shows a cross-sectional view taken along lines I 2 -I 2 of FIG. 11 ( a ).

[0166] Referring to FIG. 11 , a wiring layer 82 connected to an active region is formed on a semiconductor chip 81 , and pad electrodes 83 are formed on the wiring layer 82 .

[0167] Also, a stress buffer layer 84 is formed on the active region that is formed on the semiconductor chip 81 in a manner to expose the pad electrodes 83 . Dummy lands 85 b having dummy balls 88 a disposed thereon are provided in the four corners on the stress buffer layer 84 , and rearrangement wirings 85 a that extend over the stress buffer layer 84 are formed on the pad electrodes 83 .

[0168] Here, the rearrangement wirings 85 a and the dummy lands 85 b can be composed of, for example, a three-layer structure including a TiW-sputtered wiring layer, a Cu-sputtered wiring layer and a Cu-plated wiring layer.

[0169] Also, a solder resist film 86 is formed on the rearrangement wirings 85 a and the dummy lands 85 b , and opening sections 87 a and 87 b , which expose the rearrangement wirings 85 a and the dummy lands 85 b respectively over the stress buffer layer 84 , are formed in the solder resist film 86 .

[0170] Further, dummy balls 88 b are formed on the stress buffer layer 84 in a manner to be disposed in the four corners of the stress buffer layer 84 , and the dummy balls 88 b are disposed on the dummy lands 85 b via the opening sections 87 b that are formed in the solder resist film 86 .

[0171] Further, solder balls 88 a are disposed inside the dummy balls 88 b , and the solder balls 88 a are connected to the rearrangement wirings 85 a via the opening sections 87 a formed in the solder resist film 86 .

[0172] As a result, the solder balls 88 a are prevented from being disposed in the four corners on the outermost circumference of the stress buffer layer 84 . As the semiconductor chip 81 having the solder balls 88 a formed thereon is mounted on a mother substrate, the connection state of the solder balls 88 a can be reinforce by the dummy balls 88 b.

[0173] For this reason, even when the chip size package becomes large, poor connections of the solder balls 88 a can be reduced without increasing the number of manufacturing steps, a reduction in the throughput can be suppressed, and the reliability in the secondary mounting of the chip size package can be improved.

[0174] It is noted that the package structure described above is applicable to electronic devices, such as, for example, liquid crystal display devices, portable telephones, portable information terminals, video cameras, digital cameras, MD (Mini Disc) players and the like. By using the package structure described above, the electronic devices can be made smaller and lighter, and the reliability of the electronic devices can be improved.