Packaging substrate, method for manufacturing same, and chip packaging body having same

1. Technical Field

The present disclosure relates to chip packaging technology, and particularly to a packaging substrate, a method for manufacturing the packaging substrate, and a chip packaging body having the packaging substrate.

2. Description of Related Art

Chip packaging structure may include a packaging substrate and a chip. The PCB is configured to form a connecting pad. A typical packaging substrate includes a dielectric layer, two wiring layers arranged on opposite sides of the dielectric layer and a plurality of conductive vias formed in the dielectric layer, the vias being electrically connected to the two wiring layers. However, the conductive vias are formed through an electroplating method, which is complex and consumes too much time.

What is needed therefore is a packaging substrate, a method for manufacturing the packaging substrate, and a chip packaging body having the packaging substrate, to overcome the described limitations.

Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, all the views are schematic, and like reference numerals designate corresponding parts throughout the several views.

FIG. 1 shows a first double-sided copper clad laminate (CCL), a second double-sided copper clad laminate, a first copper foil, a second copper foil, a first adhesive sheet, a second adhesive sheet, a third adhesive sheet, a first copper foil substrate, and a second copper foil substrate according to a first exemplary embodiment.

FIG. 2 is a schematic, cross-sectional view of a supporting substrate obtained by laminating the first copper foil substrate, the second adhesive sheet, the first double-sided copper clad laminate, the first copper foil, the first adhesive sheet, the second copper foil, the second double-sided copper clad laminate, the third adhesive sheet, and the second copper foil substrate of FIG. 1 onto each other in that order.

FIG. 3 shows a photo-resist layer formed on each of the first and second copper foil substrates.

FIG. 4 shows connecting pads formed on the first copper foil substrate and the second copper foil substrate based on the photo-resist layers in FIG. 3 .

FIG. 5 shows the photo-resist layers in FIG. 4 removed.

FIG. 6 shows solder balls formed on the connecting pads in FIG. 5 .

FIG. 7 shows resin coated copper coil formed on the connecting pads and each of the first and second copper foil substrates in FIG. 6 .

FIG. 8 shows copper foil layers of the resin coated copper in FIG. 7 partly removed to form wiring layers.

FIG. 9 shows solder mask layers covering the wiring layers in FIG. 8 and exposing contact pads.

FIG. 10 shows surface plating layers formed on the contact pads in FIG. 9 .

FIG. 11 shows the multilayer structure of FIG. 10 separated, obtaining a first packaging substrate and a second packaging substrate.

FIG. 12 shows a chip attached on the first packaging substrate in FIG. 11 .

FIG. 13 shows a molding compound layer formed on the first packaging substrate and the chip in FIG. 12 .

FIG. 14 shows the first copper clad laminate, the second adhesive sheet, and a fourth copper foil of the first copper foil substrate in FIG. 13 removed.

FIG. 15 shows a third copper foil attached on a first insulating layer of the resin coated copper foil in FIG. 14 removed.

FIG. 16 shows solder balls formed on a side of the connecting pads facing away from the contact pads.

FIG. 17 shows a first double-sided copper clad laminate (CCL), a second double-sided copper clad laminate, a first copper foil, a second copper foil, a first adhesive sheet, a second adhesive sheet, a third adhesive sheet, a third copper foil, and a fifth copper foil according to a second exemplary embodiment.

FIG. 18 is a schematic, cross-sectional view of a supporting substrate obtained by laminating the third copper foil, the second adhesive sheet, the first double-sided copper clad laminate, the first copper foil, the first adhesive sheet, the second copper foil, the second double-sided copper clad laminate, the third adhesive sheet, and the fifth copper foil of FIG. 17 onto each other in that order.

FIG. 19 shows a photo-resist layer formed on each of the third copper foil and the fifth copper foil in FIG. 18 .

FIG. 20 shows connecting pads formed by partly etching the third and fifth copper foil in FIG. 19 , and the photo-resist layers in FIG. 19 removed.

FIG. 21 shows solder balls formed on the connecting pads in FIG. 20 .

FIG. 22 shows a resin coated copper coil formed on each of the first and second copper foil substrates and the connecting pads in FIG. 21 .

FIG. 23 shows copper foil layers of the resin coated copper in FIG. 22 partly removed to form wiring layers.

FIG. 24 shows solder mask layers covering the wiring layers in FIG. 23 and exposing contact pads.

FIG. 25 shows surface plating layers formed on the contact pads in FIG. 24 .

FIG. 26 shows the multilayer structure of FIG. 25 separated, obtaining a first packaging substrate and a second packaging substrate.

FIG. 27 shows a chip attached on the first packaging substrate in FIG. 26 .

FIG. 28 shows a molding compound layer formed on the first packaging substrate and the chip in FIG. 27 .

FIG. 29 shows the first copper clad laminate and the second adhesive sheet in FIG. 28 removed.

FIG. 30 shows a first copper layer attached on a first insulating layer in FIG. 29 removed.

FIG. 31 shows solder balls formed on a side of the connecting pads in FIG. 30 facing away from the contact pads.

FIGS. 1-16 show a method for manufacturing a packaging structure according to a first exemplary embodiment which includes the following steps.

FIG. 1 , shows that in step 1 , a first double-sided copper clad laminate 11 is provided, together with a second double-sided copper clad laminate 12 , a first copper foil 13 , a second copper foil 14 , a first adhesive sheet 15 , a second adhesive sheet 16 , a third adhesive sheet 17 , a first copper foil substrate 18 and a second copper foil substrate 19 .

The first double-sided copper clad laminate 11 , the second double-sided copper clad laminate 12 , the first adhesive sheet 15 , the second adhesive sheet 16 and the third adhesive sheet 17 have a same shape and area. The first copper foil 13 and the second copper foil 14 have a same shape as the first copper clad laminate 11 , and have an area smaller than that of the first copper clad laminate 11 . The first adhesive sheet 15 includes a central portion 151 and a peripheral portion 152 surrounding the central portion 151 . The central portion 151 has a shape same as that of the first and second copper foils 13 and 14 . The central portion 151 has an area slightly smaller than that of the first and second copper foils 13 and 14 .

The first copper foil substrate 18 includes a third copper foil 181 , a fourth copper foil 182 and a first adhesive layer 183 sandwiched between the third copper foil 181 and the fourth copper foil 182 . The fourth copper foil 182 is thicker than the third copper foil 181 . Preferably, the third copper foil 181 has a thickness of about 5 micrometers, and the fourth copper foil 182 has a thickness of about 18 micrometers. A thickness of the first adhesive layer 183 is in the range from about 2 micrometers to about 5 micrometers. In this embodiment, the first adhesive layer 183 is comprised of a peelable adhesive, such as a PET release film. The second copper foil substrate 19 is identical to the first copper foil substrate 18 . The second copper foil substrate 19 includes a fifth copper foil 191 corresponding to the third copper foil 181 , a sixth copper foil 192 corresponding to the fourth copper foil 182 , and a second adhesive layer 193 corresponding to the first adhesive layer 183 .

FIG. 2 shows that in step 2 , the first copper foil substrate 18 , the second adhesive sheet 16 , the first double-sided copper clad laminate 11 , the first copper foil 13 , the first adhesive sheet 15 , the second copper foil 14 , the second double-sided copper clad laminate 12 , the third adhesive sheet 17 , and the second copper foil substrate 19 are laminated together to form a supporting substrate 10 . The fourth copper foil 182 of the first copper foil substrate 18 is adjacent to the second adhesive sheet 16 . The sixth copper foil 192 of the second copper foil substrate 19 is adjacent to the third adhesive sheet 17 .

In the laminating process of step 1 , the first copper foil substrate 18 , the second adhesive sheet 16 , the first double-sided copper clad laminate 11 , the first copper foil 13 , the first adhesive sheet 15 , the second copper foil 14 , the second double-sided copper clad laminate 12 , the third adhesive sheet 17 , and the second copper foil substrate 19 are aligned with each other. The first copper foil 13 contacts the first double-sided copper clad laminate 11 , and covers and bonds the entire central portion 151 of the first adhesive sheet 15 and a portion of the peripheral portion 152 surrounding the central portion 151 . The second copper foil 14 contacts the second double-sided copper clad laminate 12 , and covers and bonds the entire central portion 151 of the first adhesive sheet 15 and a portion of the peripheral portion 152 surrounding the central portion 151 . That is, the central portion 151 of the first adhesive sheet 15 and the first doubled-sided copper clad laminate 11 are spaced by the first copper foil 13 , and the central portion 151 and the second double-sided copper clad laminate 12 are spaced by the second copper foil 14 . A portion of the peripheral portion 152 which is not covered by the first copper foil 13 and the second copper foil 14 directly bonds the first copper clad laminate 11 and the second copper clad laminate 12 .

The supporting substrate 10 includes a first surface 101 and an opposite second surface 102 . A surface of the third copper foil 181 serves as the first surface 101 . A surface of the fifth copper foil 191 serves as the second surface 102 .

The supporting substrate 10 includes a product portion 103 and an unwanted portion 104 surrounding the product portion 103 . An orthogonal projection of the product portion 103 on the first adhesive sheet 15 has a same shape as the central portion 151 and an area equal to the central portion 151 . The orthogonal projection of the product portion 103 on the first adhesive sheet 15 is aligned with the central portion 151 .

In an alternative embodiment, the first and second copper foils 13 and 14 can be omitted. That is, opposite sides of the first adhesive 15 bond the first double-sided copper clad laminate 11 and the second double-sided copper clad laminate 12 with no space between. Correspondingly, the first adhesive sheet 15 is a peelable adhesive, such as a PET release film.

FIGS. 3-5 show that in step 3 , a plurality of first connecting pads 31 is formed on the first surface 101 , and a plurality of second connecting pads 32 is formed on the second surface 102 . The first and second connecting pads 31 and 32 are located in the product portion 103 of the supporting substrate 10 .

A method for manufacturing the first connecting pads 31 and the second connecting pads 32 is described as follows. FIG. 3 shows a first photo-resist layer 41 formed on the first surface 101 , and a second photo-resist layer 42 formed on the second surface 102 . In this embodiment, the first and second photo-resist layers 41 and 42 are dry-film photo-resist. The first photo-resist layer 41 defines a plurality of first openings 411 , which expose portions of the third copper foil 181 . The second photo-resist layer 42 defines a plurality of second openings 421 , which expose portions of the fifth copper foil 191 . FIG. 4 shows the first openings 411 and the second openings 421 filled with copper by an electroplating method, thereby obtaining the first and second connecting pads 31 and 32 . FIG. 5 shows that the first and second photo-resist layers 41 and 42 are removed.

FIG. 6 shows that in step 4 , a first solder ball 21 is implanted on each of the first connecting pads 31 , and a second solder ball 22 is implanted on each of the second connecting pads 32 , using a method known in the art. The first and second solder balls 21 and 22 can be tin.

FIG. 7 shows that in step 5 , a first resin coated copper foil 23 is laminated on the first solder balls 21 , and a second resin coated copper foil 24 is laminated on the second solder balls 22 . The first resin coated copper foil 23 includes a seventh copper foil 231 and a first resin layer 232 coated on a surface of the seventh copper foil 231 . The second resin coated copper foil 24 includes an eighth copper foil 241 and a second resin layer 242 coated on a surface of the eighth copper foil 241 . The first resin layer 232 covers surfaces of the first solder balls 21 and infills the gap between the first solder balls 21 . The second resin layer 242 covers surfaces of the second solder balls 22 and infills the gap between the second solder balls 22 . Terminal portions of the first solder balls 21 facing away from the first connecting pads 31 contact and are electrically connected to the seventh copper foil 231 . Terminal portions of the second solder balls 22 facing away from the second connecting pads 32 contact and are electrically connected to the eighth copper foil 241 .

FIG. 8 shows that in step 6 , the seventh copper foil 231 is selectively etched to form a patterned first wiring layer 233 , and the eighth copper foil 241 is selectively etched to form a patterned second wiring layer 243 .

FIG. 9 shows that in step 7 , a first solder mask layer 25 is formed on the first wiring layer 233 , and a second solder mask layer 26 is formed on the second wiring layer 243 . Thus, a multi-layer structure 30 is obtained.

The first solder mask layer 25 defines a plurality of third openings 251 to expose portions of the first wiring layer 233 . The second solder mask layer 26 defines a plurality of fourth openings 261 to expose portions of the second wiring layer 243 . The portions of the first wiring layer 233 exposed through the third openings 251 serve as first contact pads 234 . The portions of the second wiring layer 243 exposed through the fourth openings 261 serve as second contact pads 244 . The first and second solder mask layers 25 and 26 can be formed by coating and then drying solder resist ink on the first wiring layer 233 and the second wiring layer 243 .

FIG. 10 shows that in step 8 , a first surface plating layer 235 is formed on each of the first contact pads 234 , and a second surface plating layer 245 is formed on each of the second contact pads 244 .

The first surface plating layer 235 and the second surface plating layer 245 can be formed by a plating of gold, of nickel-gold, of nickel-palladium-gold or of tin. The first and second surface plating layers 235 and 245 protect the first and second contacts 234 and 245 from oxidation, and is beneficial for the connection to gold wires of a chip in a later step.

FIG. 11 shows that in step 9 , a portion of the multi-layer structure 30 aligned with the unwanted portion 104 is removed. Thus, a first packaging substrate 100 and a second packaging substrate 200 are separated from each other and are respectively obtained.

The portion of the multi-layer structure 30 aligned with the unwanted portion 104 is removed by cutting or punching the multi-layer structure 30 along a borderline between the product portion 103 and the unwanted portion 104 .

Because the first copper foil 13 and the second copper foil 14 cover the entire central portion 151 of the first adhesive sheet 15 , the first adhesive sheet 15 does not adhere to the first double-sided copper clad laminate 11 and the second double-sided copper clad laminate 12 in the product portion 103 after the unwanted portion 104 is removed. The first copper foil 13 and the first double-sided copper clad laminate 11 are easily separated from each other because there is no bonding between the first copper foil 13 and the first double-sided copper clad laminate 11 . Similarly, the second copper foil 14 and the second double-sided copper clad laminate 12 are easily separated from each other. Thus, the first double-sided copper clad laminate 11 and the second double-sided copper clad laminate 12 are separated from each other.

When the first and second copper foils 13 and 14 are omitted, the first packaging substrate 100 and the second packaging substrate 200 are separated from each other by removing the first adhesive sheet 15 , such as by peeling the first adhesive sheet 15 .

The first packaging substrate 100 is identical to the second packaging substrate 200 . Thus, the first packaging substrate 100 is taken as an example for describing how a chip is mounted on the first packaging substrate 100 in the following steps.

The first and second double-sided copper clad laminate 11 and 12 reinforce and protect the layers of the first and second packaging substrates 100 and 200 in the process of manufacturing the first and second packaging substrates 100 and 200 . The first and second double-sided copper clad laminates 11 and 12 can be used instead of a polyimide (PI) sheet, a glass fiber laminate or a copper sheet.

FIGS. 12 and 13 show that in step 10 , a chip 40 is mounted on the first packaging substrate 100 and is electrically connected to the first packaging substrate 100 .

In detail, FIG. 12 shows that the chip 40 is fixed on the first solder mask layer 25 through an adhesive layer 403 . The chip 40 includes a plurality of electrodes (not shown) and a plurality of bonding wires 401 in connection with the electrodes. A terminal portion of the bonding wires 401 is soldered to the surface plating layers 235 on the first contact pads 234 , thereby electrically connecting the chip 40 to the first wiring layer 233 . The bonding wires 401 can be gold. FIG. 13 shows a molding compound layer 402 applied on the chip 40 and the packaging substrate 100 to entirely cover the bonding wires 401 , the chip 40 , an exposed portion of the first solder mask layer 25 and the surface plating layers 235 on the first contact pads 234 . In this embodiment, the molding compound layer 402 can be thermosetting resin, for example, polyimide resin, epoxy resin, or silicone resin, for example.

FIG. 14 shows that in step 11 , the first double-sided copper clad laminate 11 , the second adhesive sheet 16 , the fourth copper foil 182 and the first adhesive layer 183 are removed. Because the third copper foil 181 adjacent to the first adhesive layer 183 is thinner than the fourth copper foil 182 , the first double-sided copper clad laminate 11 , the second adhesive sheet 16 , the fourth copper foil 182 and the first adhesive layer 183 can be removed by peeling the first adhesive layer 183 from the third copper foil 181 .

FIG. 15 shows that in step 12 , the third copper foil 181 is removed. The third copper foil 181 can be removed by a micro-etching method. Thus, the first contact pads 31 are exposed.

FIG. 16 shows that in step 13 , a third solder ball 27 are implanted on each of the first contact pads 31 , thereby obtaining a chip packaging body 300 .

The chip packaging body 300 of this embodiment includes a first resin layer 232 , a plurality of first connecting pads 31 , a first wiring layer 233 , a plurality of first solder balls 21 , a first solder mask layer 25 , a chip 40 , a molding compound layer 402 and a plurality of third solder balls 27 . The first connecting pads 31 are embedded in a surface of the first resin layer 232 . The first wiring layer 233 is arranged on another surface of the first resin layer 232 facing away from the first connecting pads 31 . The first wiring layer 233 is electrically connected to the first connecting pads 31 through the first solder balls 21 located in the first resin layer 232 . Each of the connecting pads 31 is electrically connected to a first solder ball 21 . The first solder mask layer 25 is formed on the first wiring layer 233 . The first solder mask layer 25 defines a plurality of third openings 251 to expose portions of the first wiring layer 233 . The portions of the first wiring layer 233 exposed through the third openings 251 serve as first contact pads 234 . The chip 40 includes a plurality of bonding wires 401 electrically connecting the chip and the first contact pads 234 . The molding compound layer 402 entirely covers the bonding wires 401 , the chip 40 , an exposed portion of the first solder mask layer 25 and the first contact pads 234 . The third solder balls 27 are formed on a side of the first connecting pads 31 facing away from the first solder balls 21 .

In this embodiment, the first wiring layer 233 is electrically connected to the first connecting pads 31 through the first solder balls 21 instead of through conductive vias. The method of forming the first solder balls 21 is easier than the method of forming the conductive vias. In addition, the electroplating method for making the conductive vias of the related art consumes much water and needs a liquid waste treatment process. The method of forming the first solder balls 21 does not require water and the liquid waste treatment process, which is more environmentally friendly.

FIGS. 17-31 show a method for manufacturing a packaging structure according to a second exemplary embodiment includes the following steps.

FIG. 17 shows that in step ( 1 ), a first double-sided copper clad laminate 11 a is provided, together with a second double-sided copper clad laminate 12 a , a first copper foil 13 a , a second copper foil 14 a , a first adhesive sheet 15 a , a second adhesive sheet 16 a , a third adhesive sheet 17 a , a third copper foil 18 a and a fifth copper foil 19 a.

In this embodiment, the first double-sided copper clad laminate 11 a , the second double-sided copper clad laminate 12 a , the first copper foil 13 a , the second copper foil 14 a , the first adhesive sheet 15 a , and the second adhesive sheet 16 a are respectively identical to the first double-sided copper clad laminate 11 , the second double-sided copper clad laminate 12 , the first copper foil 13 , the second copper foil 14 , the first adhesive sheet 15 , and the second adhesive sheet 16 of the first exemplary embodiment. A thickness of the third copper foil 18 a and the fifth copper foil 19 a is preferably equal to or greater than about 18 micrometers.

The third copper foil 18 a is a single body of material comprising an outer first copper layer 181 a and an underlying second copper layer 182 a . The fifth copper foil 19 a is single body of material comprising an outer third copper layer 191 a and an underlying fourth copper layer 192 a . As shown in FIG. 17 , the first copper layer 181 a and the second copper layer 182 a are partitioned by an imaginary line 183 a , and the third copper foil 191 a and the fourth copper layer 192 a are partitioned by an imaginary line 193 a . In this embodiment, the first copper layer 181 a has a thickness equal to the second copper layer 182 a , and the third copper layer 191 a has a thickness equal to the fourth copper layer 192 a.

FIG. 18 shows that in step ( 2 ), the third copper foil 18 a , the second adhesive sheet 16 a , the first double-sided copper clad laminate 11 a , the first copper foil 13 , the first adhesive sheet 15 , the second copper foil 14 , the second double-sided copper clad laminate 12 , the third adhesive sheet 17 , and the fifth copper foil 19 a are laminated together to form a supporting substrate 10 a.

In the laminating process of step ( 2 ), the third copper foil 18 a , the second adhesive sheet 16 a , the first double-sided copper clad laminate 11 a , the first copper foil 13 a , the first adhesive sheet 15 a , the second copper foil 14 a , the second double-sided copper clad laminate 12 a , the third adhesive sheet 17 a , and the fifth copper foil 19 are aligned with each other. The first copper foil 13 a contacts the first double-sided copper clad laminate 11 a , and covers and bonds the entire central portion 151 a of the first adhesive sheet 15 a and a portion of the peripheral portion 152 a of the first adhesive sheet 15 a surrounding the central portion 151 a . The second copper foil 14 a contacts the second double-sided copper clad laminate 12 a , and covers and bonds the entire central portion 151 a of the first adhesive sheet 15 a and a portion of the peripheral portion 152 a surrounding the central portion 151 a . That is, the central portion 151 a of the first adhesive sheet 15 a and the first doubled-sided copper clad laminate 11 a are spaced by the first copper foil 13 a , and the central portion 151 a and the second double-sided copper clad laminate 12 a are spaced by the second copper foil 14 a . A portion of the peripheral portion 152 a which is not covered by the first copper foil 13 a and the second copper foil 14 a directly bonds the first copper clad laminate 11 a and the second copper clad laminate 12 a.

The supporting substrate 10 a includes a first surface 101 a and an opposite second surface 102 a . A surface of the first copper layer 181 a of the third copper foil 18 a serves as the first surface 101 a . A surface of the third copper layer 191 a of the fifth copper foil 19 a serves as the second surface 102 a.

The supporting substrate 10 a includes a product portion 103 a and an unwanted portion 104 a surrounding the product portion 103 a . An orthogonal projection of the product portion 103 a on the first adhesive sheet 15 a has a same shape as the central portion 151 a and an area equal to the central portion 151 a . The orthogonal projection of the product portion 103 a on the first adhesive sheet 15 a is aligned with the central portion 151 a.

In an alternative embodiment, the first and second copper foils 13 a and 14 a can be omitted. That is, opposite sides of the first adhesive 15 a bond the first double-sided copper clad laminate 11 a and the second double-sided copper clad laminate 12 a with no space between. Correspondingly, the first adhesive sheet 15 a is a peelable adhesive, such as a PET release film.

FIGS. 19-20 show that in step ( 3 ), a plurality of first connecting pads 31 a is formed at the first surface 101 a side, and a plurality of second connecting pads 32 a is formed on the second surface 102 a side. The first and second connecting pads 31 a and 32 a are located in the product portion 103 a of the supporting substrate 10 a.

A method for manufacturing the first connecting pads 31 a and the second connecting pads 32 a is described as follows. FIG. 19 shows that a first photo-resist layer 41 a is formed on the first surface 101 a , and a second photo-resist layer 42 a is formed on the second surface 102 a . The first photo-resist layer 41 a defines a plurality of first openings 411 a , which expose portions of the first copper layer 181 a of the third copper foil 18 a . The second photo-resist layer 42 a defines a plurality of second openings 421 a , which expose portions of the third copper layer 191 a of the fifth copper foil 19 a . FIG. 20 shows that the first copper layer 181 a and the third copper layer 191 a are etched based on the first and second photo-resist layers 41 a and 42 a , thereby forming the first connecting pads 31 a and the second connecting pads 32 a . Then the first and the second photo-resist layers 41 a and 42 a are removed. The etching depth of the third copper foil 18 a is equal to the thickness of the first copper layer 181 a . The etching depth of the fifth copper foil 19 a is equal to the thickness of the third copper layer 191 a . That is to say, the second copper layer 182 a and the fourth copper layer 192 a are not etched, and are respectively exposed through the gaps between the first connecting pads 31 a and between the second connecting pads 32 a.

FIG. 21 shows that in step ( 4 ), a first solder ball 21 a is implanted on each of the first connecting pads 31 a , and a second solder ball 22 a is implanted on each of the second connecting pads 32 a , using a method known in the art. The first and second solder balls 21 a and 22 a can be tin.

FIG. 22 shows that in step ( 5 ), a first resin coated copper foil 23 a is laminated on the first solder balls 21 a , and a second resin coated copper foil 24 a is laminated on the second solder balls 22 a . The first resin coated copper foil 23 a includes a seventh copper foil 231 a and a first resin layer 232 a coated on a surface of the seventh copper foil 231 a . The second resin coated copper foil 24 a includes an eighth copper foil 241 a and a second resin layer 242 a coated on a surface of the eighth copper foil 241 a . The first resin layer 232 a covers surfaces of the first solder balls 21 a and infills the gap between the first solder balls 21 a . The second resin layer 242 a covers surfaces of the second solder balls 22 a and infills the gap between the second solder balls 22 a . Terminal portions of the first solder balls 21 a facing away from the first connecting pads 31 a contact and are electrically connected to the seventh copper foil 231 a . Terminal portions of the second solder balls 22 a facing away from the second connecting pads 32 a contact and are electrically connected to the eighth copper foil 241 a.

FIG. 23 shows that in step ( 6 ), the seventh copper foil 231 a is selectively etched to form a patterned first wiring layer 233 a , and the eighth copper foil 241 a is selectively etched to form a patterned second wiring layer 243 a.

FIG. 24 shows that in step ( 7 ), a first solder mask layer 25 a is formed on the first wiring layer 233 a , and a second solder mask layer 26 a is formed on the second wiring layer 243 a . Thus, a multi-layer structure 30 a is obtained.

The first solder mask layer 25 a defines a plurality of third openings 251 a to expose portions of the first wiring layer 233 a . The second solder mask layer 26 a defines a plurality of fourth openings 261 a to expose portions of the second wiring layer 243 a . The portions of the first wiring layer 233 a exposed through the third openings 251 a serve as first contact pads 234 a . The portions of the second wiring layer 243 a exposed through the fourth openings 261 a serve as second contact pads 244 a . The first and second solder mask layers 25 a and 26 a can be formed by coating and then drying solder resist ink on the first wiring layer 233 a and the second wiring layer 243 a.

FIG. 25 shows that in step ( 8 ), a first surface plating layer 235 a is formed on each of the first contact pads 234 a , and a second surface plating layer 245 a is formed on each of the second contact pads 244 a.

The first surface plating layer 235 a and the second surface plating layer 245 a can be formed by a plating of gold, of nickel-gold, of nickel-palladium-gold or of tin. The first and second surface plating layers 235 a and 245 a protect the first and second contacts 234 a and 245 a from oxidation, and is beneficial for the connection to gold wires of a chip in a later step.

FIG. 26 shows that in step ( 9 ), a portion of the multi-layer structure 30 a aligned with the unwanted portion 104 a is removed. Thus, a first packaging substrate 100 a and a second packaging substrate 200 a are separated from each other are respectively obtained.

The portion of the multi-layer structure 30 a aligned with the unwanted portion 104 a is removed by cutting or punching the multi-layer structure 30 a along a borderline between the product portion 103 a and the unwanted portion 104 a.

Because the first copper foil 13 a and the second copper foil 14 a cover the entire central portion 151 a of the first adhesive sheet 15 a , the first adhesive sheet 15 a does not adhere to the first double-sided copper clad laminate 11 a and the second double-sided copper clad laminate 12 a in the product portion 103 a after the unwanted portion 104 a is removed. The first copper foil 13 a and the first double-sided copper clad laminate 11 a are easily separated from each other because there is no bonding between the first copper foil 13 a and the first double-sided copper clad laminate 11 a . Similarly, the second copper foil 14 a and the second double-sided copper clad laminate 12 a are easily separated from each other. Thus, the first double-sided copper clad laminate 11 a and the second double-sided copper clad laminate 12 a are separated from each other.

When the first and second copper foils 13 a and 14 a are omitted, the first packaging substrate 100 a and the second packaging substrate 200 a are separated from each other by removing the first adhesive sheet 15 a , such as by peeling the first adhesive sheet.

The first packaging substrate 100 a is identical to the second packaging substrate 200 a . Thus, the first packaging substrate 100 a is taken as an example for describing how a chip is mounted on the first packaging substrate 100 a in the following steps.

FIGS. 27 and 28 show that in step ( 10 ), a chip 40 a is mounted on the first packaging substrate 100 a and is electrically connected to the first packaging substrate 100 .

In detail, FIG. 27 shows that the chip 40 a is fixed on the first solder mask layer 25 a through an adhesive layer 403 a . The chip 40 a includes a plurality of electrodes (not shown) and a plurality of bonding wires 401 a connecting with the electrodes. A terminal portion of the bonding wires 401 a is soldered to the surface plating layers 235 a on the first contact pads 234 a , thereby electrically connecting the chip 40 a to the first wiring layer 233 a . The bonding wires 401 a can be gold. FIG. 13 shows that a molding compound layer 402 a is applied on the chip 40 a and the packaging substrate 100 a to entirely cover the bonding wires 401 a , the chip 40 a , an exposed portion of the first solder mask layer 25 a and the surface plating layers 235 a on the first contact pads 234 a . In this embodiment, the molding compound layer 402 a can be thermosetting resin, for example, polyimide resin, epoxy resin, or silicone resin, for example.

FIG. 29 shows that in step ( 11 ), the first double-sided copper clad laminate 11 a , and the second adhesive sheet 16 a are removed. The first double-sided copper clad laminate 11 a and the second adhesive sheet 16 a can be removed by peeling the second adhesive sheet 16 a from the second copper layer 182 a of the third copper foil 18 a.

FIG. 30 shows that in step ( 12 ), the second copper layer 182 a of the third copper foil 18 a is removed. The second copper layer 182 a can be removed through a micro-etching method. Thus, the first contact pads 31 are exposed.

FIG. 31 shows that in step 13 , a third solder ball 27 a is implanted on each of the first contact pads 31 a , thereby obtaining a chip packaging body 300 a . The chip packaging body 300 a is similar to the chip packaging body 300 , the differences being that the connecting pads 31 a are made by etching a copper foil.

While certain embodiments have been described and exemplified above, various other embodiments will be apparent from the foregoing disclosure to those skilled in the art. The disclosure is not limited to the particular embodiments described and exemplified but is capable of considerable variation and modification without departure from the scope and spirit of the appended claims.