TW516352B - Manufacturing method for printed circuit board - Google Patents

Abstract

A manufacturing method for printed circuit board comprises mainly fixing and electrically connecting a first substrate to a second substrate having an opening by solder balls, stud solder bumps, or anisotropic conductive adhesive films such that a multi-layered printed circuit board having trough or three dimensional structure is obtained. The surface of the first substrate is provided with a first set of bonding pads to electrically connect a semiconductor chip and a second set of bonding pads. The bottom surface of the first substrate is provided with a third set of bonding pads to electrically connect an external printed circuit board. The third set of bonding pads are connected electrically to the first and the second bonding pads. The bottom surface of the second substrate contains a set of bonding pads.

Description

516352 V. Description of the invention (l) [Field of the Invention_ This invention relates to a method for manufacturing a multilayer printed circuit board. [Previous technology]: The circuit board is usually made of a layer of conductive material (usually copper or solder-plated = i) carried on a core layer made of an insulating material (usually a glass fiber reinforced ring η). A printed circuit board has two Layer conductive circuit board. In order to accommodate more circuits on both sides of the electrical layer, it is called double-layer electricity. The conductive circuit is clamped in the previous circuit board. Generally, a number of circuit clamps δ are placed between the dielectric layers to make a multilayer circuit. The printed circuit board of the evening layer-generally the inner core layer described later (for example, FR-4 f) ^ / Cheng. Baixian, edge for one side. After that, _ engraved = to be attached; f two layers above and below (for example Prepreg conductors (dielectrics) are staggered on the circuit with a lightning conductor and a conductive circuit (made of copper foil-stacked, with phases: both sides to form a body. Then, the multilayer printing is formed. There is a pre-dip etched between ^ and ^ to form the desired conductive electrode, and then connect the 片 piece. Finally, change the ；; 70 pieces of electronics (such as the resin material of the semiconductor ^ body) to make the stack Pressed to cure the total number of layers of the prepreg impregnated body and the copper foil 13 people 113 7 6). The pre- and each silver carved into the required electricity = two 3 copper layers on the upper and lower sides of the copper box layer generally use four or four layers (,, ;; poise layer) as required , But the electrical properties between the circuit layers are: "::: In general, different through-holes, and / drilled through holes in the layer wish, coated in this through-hole conductive metal And up to P01-003.ptd 516352 5. Description of the invention (2). However, as far as multilayer printed circuit boards are concerned, through holes and their hole pads are one of the main factors limiting the density of circuits. Hole pads are usually larger than the hole diameter. 〇 · 2mm 'to compensate for drill misregistration,% expansion and contraction of the laminate (1 a in nateexpas 丨 0 n / shrinkage) and exposure equipment white, J% expansion and contraction (photo ί〇〇) · Expasion / shrinkage). In addition, the inner layer through-hole pads in a multilayer structure are more difficult to control the positional relationship because they cannot be seen from the outside, so the hole pads are larger than the aperture by about 0.5-0.8 mm. Circuit design is not easy to achieve true high density. [Summary of the invention] u = this' The main object of the invention to provide a method for manufacturing a multilayer printed circuit board 'which may be overcome or at least ameliorate the aforementioned problems of the prior art. The method of manufacturing a multilayer printed circuit board according to the present invention, which mainly comprises

A first substrate is fixed and electrically connected to a second substrate having an opening by using a solder ball, a columnar solder bump, or an anisotropic conductive adhesive film (ACF), thereby preparing a groove or 3D structured multilayer printed circuit board. The first surface of the first substrate is provided with a first group of pads for electrically connecting to a semiconductor wafer and the second group of pads, and the lower surface of the first substrate is provided with a third group of pads for electrically connecting to a For an external printed circuit board, the third group of pads in # is electrically connected to the first group of pads and the second group of pads. The second substrate has a set of connection pads disposed on a lower surface thereof. It is worth knowing that the first substrate and the second substrate are not laminated and bonded to each other by using a conventional Prepreg and a hot pressing method. this

Page 5 516352 V. Description of the invention (4) A core layer made of fiberglass reinforced epoxy resin is formed, thereby increasing the mechanical strength of the multilayer printed circuit board. In addition, the substrate used in the present invention may include a through-hole and the through-hole is coated with a conductive metal to form an electrical connection between different conductive circuit layers in the same substrate. In addition, the surface of the substrate used in the present invention preferably has a layer of solder resist (not shown) covered thereon, and the solder resist layer corresponds to a pad (for example, a pad 1 l0a) , UOb, 1 10c or connection pad 1210)) is provided with an opening so that the pad is exposed on the solder resist layer. Then, a plurality of solder balls 1 30 are set on the connection pads 1 2 b of the substrate 1 2 Q or the second group of pads 11 0 b of the substrate 1 10. In detail, it can be achieved by the following steps: (a) the solder ball 130 is mounted on a fixture, the fixture has a plurality of holes, the arrangement of which corresponds to the desired ball grid array; (b) a total of Eutectic tin is printed on the connection pad i20b or the second set of pads ii〇b; (c) using a vacuum nozzle 'to suck the solder balls arranged on the fixed parts to the metal Solder paste on the pad; then (d) re-solder (melt the tin only). ~ Next 'Place the substrate 120 on the top surface of the substrate 110, so that the first group of pads 110a are exposed at the opening i20a and the connection pads 120b of the substrate 120 are aligned with the second group of substrates 110 Pad noob. At this time, the solder balls on one substrate are aligned with the corresponding pads on the other substrate, and the solder paste has been printed on the pads first. Then, in another re-soldering process, the solder paste will melt to form a solder bond between the pads corresponding to the substrate Π 0 and 120. P01-003.ptd V. Description of the invention (5) Referring to the second figure, the method for manufacturing a multilayer printed circuit board 200 according to the second preferred embodiment of the present invention is characterized in that the base 200 bumps: 5. It is fixed and electrically connected to the substrate n. . The columnar solder 150 is firstly formed by stencil printing on the connection pad 1201 of the base = 120 or the second set of pad u0b of the substrate 11, and then the solder bump is re-soldered. Block 150, whereby the substrate 120 is fixed and the board 110 is electrically connected. It is assumed that the method for manufacturing a multilayer printed circuit board according to the first and second preferred embodiments of the present invention preferably further includes an adhesive filling process. In detail, the underfill 140 uses an automated underfill (/ dispense system) to place the underfill material on the edges of the gap between the substrates 110 and 120. The glue filling material is then sucked into the space by capillary action to complete the glue filling process. Next, the product of the filling process is moved to an underfill curing oven, and the filling ho is then cured. First, a plurality of metal bumps 160 are formed on the substrate 120. Referring to the third figure, a method for manufacturing a multilayer printed circuit board 300 according to a third preferred embodiment of the present invention includes the following steps:

Si 120b. It can be understood that the plurality of metal bumps 6o can also be formed on the second group of pads 11b of the substrate 110. The metal bump 1 60 is preferably a stud bump formed by a conventional wire bonding technique (wiir b ο n d i n g t e c h n i q u e). In addition, the metal bump i60 can be formed by using a conventional bumping technology, which includes step (A) forming an under bump metallurgy (UBM) on a plurality of pads of the substrate, E.g. electroless nickel / gold (eiectf〇iess

516352 V. Description of Invention (6)

Ni / Au) forms UBM; and (B) forms metal bumps on UBM, and the methods of planting balls include steaming, electroplating, and printing. Then, the substrate 1 2 0 is placed on the upper surface of the substrate 110 using an anisotropic conductive adhesive layer (ac F) 1 70 so that the first group of pads 丨 丨 〇a is exposed at the opening 120a and the substrate The connecting pads of 2o 2b are aligned with the second set of pads 1 1 0 b of the substrate 11 {). An anisotropic adhesive suitable for forming the anisotropic conductive adhesive layer 170 is known as a "z-axis anisotropic adhesive", which is filled with conductive particles 170a at a low concentration and placed on the xy plane. Will not touch each other. Therefore, compressing the substance in the z direction will establish a conductive path. Next, after performing a thermocompression process (thermoccmpressio), the substrate 120 is bonded to the substrate 1 through the anisotropic conductive adhesive layer 17o, and the metal bump 16 on the connection pad 12013 is made. 〇 is electrically connected to the corresponding second group of pads 11 through conductive particles I 7 0 a. It can be understood that the anisotropic | green conductive adhesive layer can be thermoplastic or thermosetting. The thermoplastic anisotropic rubber is first heated and softened and then cooled and solidified. Thermosetting anisotropic adhesive Heat 100 to 300. . It can be cured for several minutes to one hour or more. According to the manufacturing method of the multilayer printed circuit board of the present invention, since the substrates II 0 and 120 are independently made and tested, the solder balls, columnar solder bumps, or anisotropic conductive adhesive layers are used to fix and electrically connect each other. Because of the electrical connection, the electrical connection between the substrates 110 and 120 does not require the use of a via. Please refer to the fourth figure, which discloses the use of the multilayer printed circuit board 100 of the present invention.

516352 V. Description of the invention (7) 20%, the semiconductor wafer # assembly & mainly includes a wafer 180 which is carried on a child-layer printed circuit board 100. The wafer 1 800 is provided with a die attach material on the concave portion of the multi-layer printed circuit board, and then a wire bonding machine (such as a gold wire) is bonded to the wafer. 8 Wafer pads and a first set of pads 110a. Then, the transfer molding method seals the wafer 180 in a colloid 182. It can be understood that the sealant 182 can also be formed by a glOb process. Although the semiconductor chip package structure according to the fourth figure of the present invention takes a multi-layer printed circuit board 1000 as a preferred embodiment, the multi-chip package structure according to the present invention can also utilize a multilayer printed circuit board 2000 or 300. . Please refer to the fifth figure, which discloses a multi-chip package structure formed by using the multilayer printed circuit board of the present invention, which is further characterized by including a wafer ΐ9θ recessed in a multilayer printed circuit board 400, wherein the multilayer The printed circuit board 400 is fixed with a solder ball and electrically connected to the multilayer printed circuit board 100. It can be understood that the multilayer printed circuit board 400 can also be fixed and electrically connected to the printed circuit board 100 with a columnar solder bump or an anisotropic conductive adhesive layer (ACF). Preferably, the chips 180 and 190 can be individually packaged and tested, and then the multilayer printed circuit board 400 is mounted on the multilayer printed circuit board 100. The chip package structure according to the present invention can be mounted on an external substrate, such as a printed circuit board, using solder balls. It can be understood that the pads at the bottom of the package structure can also be printed with solder paste before being mounted on the external substrate. Although the present invention has been disclosed in the foregoing preferred embodiments, it is not limited thereto

P01-003.ptd Page 10 516352 V. Description of the invention (8) Anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

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Claims (1)

516352 VI. Application for Patent Scope 1. A printed circuit board manufacturing method, which includes the following steps: Provide a first substrate with an upper surface and a lower surface, and a first set of pads on the upper surface of the board for electrical properties Connected to the half conductor = and the second set of pads, * 玄 筮 _ I 丁生士 you one-day, day and month connection 5 flute & bottle connection, the first substrate table has a third set of pads electrically connected to the first And a pad and a second set of pads; providing a second substrate having an opening therein and a set of connection pads provided on its lower surface; placing a plurality of solder balls on the second pad's connection pad or Group pads of the first substrate; ^ Place the first substrate on the upper surface of the first substrate so that the first group of pads are exposed at the opening and the connection pads of the second substrate are aligned with the first of the first substrate Assembling the substrate; and performing a re-soldering step, thereby fixing and electrically connecting the second substrate to the first substrate. ^, _ The method for manufacturing a printed circuit board according to item i in the scope of the patent application, wherein: {The third group of pads is used to electrically connect to an external printed circuit board. 8. The method for manufacturing a printed circuit board according to item 1 of the scope of patent application, which further includes forming a first underfill between the first substrate and the second substrate. ^ A printed circuit board manufacturing method including the following steps: Provide-a first substrate has an upper surface and a lower surface, and a first set of pads is provided on the first base surface for electrically connecting to a semiconductor wafer 516352 6. Scope of patent application · And a second set of pads, the lower surface of the first substrate is provided with a third set of pads electrically connected to the first set of pads and the second set of pads; a second substrate is provided with / opening It is set in it and a set of connection pads 嗖 on its lower surface; stencil printing a plurality of columnar solder bumps on the connection pads of the second substrate or the second set of connection pads of the first substrate; An upper surface of a substrate such that the first group of pads are exposed at the opening and the connection pads of the second substrate are aligned with the second group of pads of the first substrate; and the solder bump is re-soldered, thereby The two substrates are fixed and electrically connected to the first substrate. ^ The method for manufacturing a printed circuit board according to item 4 of the scope of patent application, wherein the third group of pads is used to be electrically connected to an external printed circuit board. / Other reasons I. 5. A method for manufacturing a printed circuit board according to item 4 of the scope of patent application, including forming an underfill on the first substrate and the second substrate 7. A method for manufacturing a printed circuit board, including the following: Steps: Provide a first substrate with an upper surface and a lower surface, the first surface of the first substrate is provided with a first set of pads for electrically connecting to a semiconductor wafer and the first set of pads under the first substrate A third set of pads is electrically connected to the first set of pads and the second set of pads on the surface; a second substrate is provided with an opening therein and a set of connection pads P01-003.ptd Page 15 516352 On its lower surface; the connection pads of the two substrates or the first substrate form a plurality of metal bumps on the second group of pads; the second substrate uses an anisotropy ^ j-a. ^ 11 conductive knee layer (ACF ) Placed on the first substrate * <-^ clothing surface to make the first set of twists a, "Every New Year's Eve, hit the M batch / M ten Λ connection is exposed on the opening and the second substrate connection pad Is the first set of pads aligned with the first base ^ — Φ pole; and performing the hot-pressing step, by way of praise _, S / * ρ η X m ^, the younger substrate is hunted by the anisotropic conduction The adhesive layer UCF) is fixed and electrically connected to the first substrate. I according to SH patent | & 7th printed circuit board manufacturing method The third group of pads is used to electrically connect to an external printed circuit board A method for manufacturing a board, wherein the genus and dog block are stud bumps formed by a conventional wire bonding technique.