Manufacturing method for cavity-down plastic ball grid array package substrate

Manufacturing method of plastic ball grid array packaging substrate with downward opening

The present invention provides a method for manufacturing a package substrate, especially a method for manufacturing a cavity-down (CD) plastic ball grid array (PBGA) package substrate.

With the development of IC technology, the integration of semiconductor chips has gradually increased, and the number of input and output pins (signal, power, ground) of the package chip has also increased, resulting in the continuous development of various high-density package substrates , CD-PBGA package substrate is an example. The CD-PBGA package substrate currently on the market is applied to a ball grid array (BGA) package with high heat dissipation quality. Generally, the number of output and input terminals of the CD-PBGA package substrate is between 300 and 800, and the operating power range is between 5-10 watts or even higher. The heat dissipation of the CD-PBGA package substrate can be improved by forced air convection, such as installing a cooling fan on the top of the CD-PBGA package substrate.

At present, in the field of cavity down ball grid array (CD-BGA) packaging technology, several inventions have been proposed and patented. For example: US Patent No. 5,027, 191 proposes an opening-down wafer carrying structure with an array of pads, while US Patent No. 5,420,460 proposes an application for gold wire ( Wirebonding) technology thin CD-BGA package structure.

Please refer to FIGS. 1 and 2. FIG. 1 is a schematic diagram of a conventional plastic ball grid array package substrate 10 with an opening downward, and FIG. 2 is a schematic cross-sectional view of the package substrate 10 in FIG. The CD-PBGA package substrate 10 (as shown in FIG. 1) completed by the conventional method includes an organic substrate 12 and a Cu heat spreader 14. A square cavity 16 is provided in the center of the plastic substrate 12 for accommodating an IC die 18. The "opening downward" mentioned here means that the CD-PBGA package substrate 10 will be combined with the circuit board (PCB) with the opening downward, and the heat dissipating copper sheet 14 will be located above to facilitate heat dissipation.

As shown in Figures 1 and 2, the surface of the plastic substrate 12 is provided with a plurality of bonding fingers 20 and ball pads 22, and a plurality of conductive circuits 23 (only shown in Figure 1 Part of the conductive circuit) is used to connect the wire bonding gold finger 20 and the solder ball bonding pad 22. A copper wire layer 24 is provided on the other side of the plastic substrate 12. The plastic substrate 12 includes a plurality of circuit vias 26 for connecting the bonding gold fingers 20, the solder ball bonding pads 22, the conductive circuit 23 and the copper wire layer 24. The surface of the plastic substrate 12 is coated with a green paint layer (solder mask) 28 to protect the package substrate 10, isolate the contacts 20 and 22, and cover the conductive circuit 23. The surface of each contact 20 and 22 is plated with a nickel (Ni) metal layer 30 and a pure gold (Au) metal layer 32 successively. The plastic substrate 12 and the heat dissipation copper sheet 14 are bonded with an adhesive film 34, and the surface of the heat dissipation copper sheet 14 is additionally plated with a nickel-plated finish 36 to protect the heat dissipation copper sheet 14 and prevent the heat dissipation copper sheet 14 Oxidation. The generally used adhesive film 34 is epoxy-based prepreg, and other adhesive tapes or adhesive films can also be used.

After the IC chip 18 is attached to the opening 16 of the package substrate 10 with epoxy compound, then the IC chip 18 is electrically connected to the bonding wire through a plurality of metal wires 38 by means of wire bonding. On the golden finger 20, globtop (not shown) is then injected into the area of the opening 16 to encapsulate the IC chip 18. Then, Pb/Sn solder balls (Pb/Sn solder balls) 40 are planted on each of the solder ball pads 22 to connect with the circuit board (not shown) below. The current output by the IC chip 18 is transmitted to the wire bonding gold finger 20 of the package substrate 10 via the metal wire 38, and then via the conductive circuit 23 (or via the conductive circuit 23-circuit conduction 26-copper wire layer 24- circuit conduction 26-conductive line 23 ) Is transmitted to the solder ball pad 22, and finally the current output by the IC chip 18 is transmitted to the circuit board via the lead solder ball 40. Similarly, the circuit board can input current into the IC chip 18 through the same route and in the opposite direction.

The conventional manufacturing method of the package substrate 10 is to first manufacture the plastic substrate 12 and the heat dissipation copper sheet 14 respectively, and finally press the plastic substrate 12 and the heat dissipation copper sheet 14 together. In the conventional method, the wire bonding gold finger 20, the solder ball bonding pad 22, the conductive circuit 23, the copper wire layer 24, and the circuit conduction 26 are first fabricated on the plastic substrate 12 where the opening 16 has not been formed, and then the plastic substrate 12 and the contacts 20, 22 The green paint layer 28 is coated on the entire surface on the same side, and then a developing and etching process is used to form a pattern of the green paint layer 28.

After the green paint layer 28 is formed, a tape or dry film (not shown) is attached to the other side of the plastic substrate 12 (the same side as the copper wire layer 24) to perform a single-sided (and The nickel/gold plating process on the same side of the conductive circuit 23). In the nickel/gold plating process, a nickel metal layer 30 with a thickness of about 5 microns (micron, μm) is plated on the surface of each contact 20, 22 of the plastic substrate 12, and then a pure gold metal layer with a thickness of about 0.5 microns is plated on the surface of the nickel metal layer 30. Layer 32. After the nickel/gold plating process is completed, the tape or dry film on the back of the plastic substrate 12 is removed, and then a milling cutter, etc. are used to form a square opening 16 in the center of the plastic substrate 12 and clean it.

After the opening 16 is formed, a single-side Cu surface pre-treatment process is then performed to form an oxide layer 42 on the copper wire layer 24 on one side of the plastic substrate 12, using The rougher oxide layer 42 increases the adhesion on the surface of the plastic substrate 12. The oxide layer 42 may be composed of black oxide or brown oxide.

While making the plastic substrate 12, first stick a tape or dry film (not shown) on one side of the heat sink copper sheet 14 to perform a nickel plating process on the other side. A nickel plating layer 36 is plated on the surface of the side. After the nickel plating process is completed, the tape or dry film on the back of the heat sink copper sheet 14 is removed, and then a single-sided copper surface roughening process is performed on one side of the heat sink copper sheet 14 (the other side opposite to the nickel plating layer 36) An oxide layer 44 is formed on the surface to increase the adhesion on the surface of the heat dissipation copper sheet 14. The oxide layer 44 may also be composed of a black oxide layer or a brown oxide layer.

Please refer to FIGS. 3 and 4. FIG. 3 is a schematic diagram of the high-temperature pressing process of the conventional manufacturing method of the package substrate 10, and FIG. 4 is a schematic diagram of removing the release film 48 and the filling layer 46 after the conventional high-temperature pressing process. After the plastic substrate 12 and the heat dissipation copper sheet 14 have completed the aforementioned manufacturing process, a high-temperature lamination process is then prepared to press the opened plastic substrate 12 and the heat dissipation copper sheet 14 into the package substrate 10.

As shown in FIG. 3, during the high temperature pressing process, the adhesive film 34 may flow into the opening 16 of the plastic substrate 12. Therefore, a filler film 46 must be placed on the plastic substrate 14 in advance. The packing layer 46 can be made of polyethylene or silicone resin. During the high-temperature pressing process, the filling layer 46 first flows into the opening 16 of the plastic substrate 12 to prevent the adhesive film from flowing into the opening 16. After the high-temperature pressing process is completed, the filling layer 46 must be completely removed. Therefore, before placing the filling layer 46, a release film 48 is placed on the plastic substrate 12 first. The release film 48 can be easily torn off from the plastic substrate 12 to assist in the complete removal of the packing layer 46.

Before the high-temperature pressing process, in addition to placing the release film 48 and the packing layer 46 on the plastic substrate 12, the adhesive film 34 must also form an opening 50 in the center. The opening 50 and the opening 16 of the plastic substrate 12 correspond to each other, so as to prevent the adhesive film 34 from remaining in the opening 16 after the packaging substrate 10 is completed.

After the foregoing process is completed, a high-temperature pressing process can be performed to align the plugging layer 40 with the release film 48, the opened plastic substrate 12, and the opened adhesive film 34 and the heat sink 14 They are stacked in series, and then pressed together at high temperature to form the package substrate 10. As shown in FIG. 4, the release film 48 is then torn off from the packaging substrate 10, and the filling layer 46 can be removed at the same time. Subsequently, a thermal treatment process is performed on the package substrate 10 to control the warpage of the package substrate 10 and to make the adhesive film 34 more cured, so that the plastic substrate 12 and the heat sink 14 Closely integrated.

At present, in the manufacture of package substrate 10 in the industry, many CD-PBGA package substrates are manufactured on a substrate (not shown) at the same time, and then a piece singulation process is used to produce the finished substrate. Cut into individual package substrates 10. Before the monolithic cutting process, according to the requirements of the process, a plurality of tooling holes (tooling holes) may be formed in the unused part of the original substrate and then cut, or each package substrate 10 may be cut directly. After the monolithic cutting process is completed, each package substrate 10 is inspected to ensure that each package substrate 10 meets the industry standard specifications.

In the current method of manufacturing the CD-PBGA package substrate 10, there are the following shortcomings:

First, when performing a single-sided nickel plating process on the heat sink copper sheet 14, tape or dry film must be pasted on the other side of the heat sink copper sheet 14, and then after the nickel plating process is completed, the tape or dry film Remove. Regardless of whether the adhesive tape (or dry film) is attached or removed, the process is quite complicated, which causes the production cost of the package substrate 10 to be high and increases the complexity of the manufacturing process.

Second, the nickel-plated layer 36 on the heat dissipation copper sheet 14 will cause the heat dissipation copper sheet 14 to withstand higher stress, which in turn affects the bending of the package substrate 10 and makes the package substrate 10 more likely to be uneven. .

Third, the coefficient of thermal expansion (CTE) of epoxy compound (used to bond IC chip 18) is between 50~60 ppm/°C, and the coefficient of thermal expansion of heat sink 14 is about 17 ppm/ °C, the two do not match. Due to the high temperature experienced in the subsequent substrate packaging process and the substrate soldering process to the printed circuit board, the IC chip 18 will also generate high temperature during operation, and the epoxy resin and the heat dissipation copper sheet 14 will have different thermal expansions, thus making the epoxy resin (Below the IC chip 18) bear high stress, and it is not easy to closely adhere to the heat dissipation copper sheet 14.

Fourth, in the conventional method for manufacturing the package substrate 10, the nickel metal layer 30 and the pure gold metal layer 32 on the wire bonding gold finger 20 and the solder ball pad 22 are completed before the high temperature pressing process, and the surface of the pure gold metal layer 32 The chance of being contaminated or damaged by other processes has increased significantly.

Fifth, in the conventional method, the open-hole adhesive film 34 is used to bond the plastic substrate 12 and the heat dissipation copper sheet 14, but the process of forming the precise opening 50 on the adhesive film 34 is difficult and expensive. It is also quite difficult to accurately align and stack the holed plastic substrate 12, the holed adhesive film 34, and the heat dissipation copper sheet 14 together. In addition, the use of the release film 48 and the packing layer 46 in the high temperature pressing process is very inconvenient and very uneconomical.

Therefore, the main purpose of the present invention is to provide a manufacturing process (Manufacturing Process) of a CD-PBGA package substrate to solve the above-mentioned conventional problems and further reduce the production cost.

Please refer to FIG. 5 and FIG. 6. FIG. 5 is a schematic diagram of a plastic ball grid array package substrate 60 with downward opening according to the present invention, and FIG. 6 is a cross-section of the package substrate 60 in FIG. Schematic. The present invention is a method for manufacturing a two-layer or multi-layer plastic ball grid array package substrate with an opening downward. In this article, the manufacturing method of a two-layer CD-PBGA package substrate 60 is mainly described. , But the same production method can be applied to the production of four-layer or other multi-layer CD-PBGA package substrates.

As shown in FIG. 5, the double-layer CD-PBGA package substrate 60 completed by the method of the present invention includes a plastic substrate 62 and a heat dissipation copper sheet 64. The central part of the plastic substrate 62 is provided with a square or rectangular opening 66 for accommodating an IC chip 68. The material of the plastic substrate 62 may have a high glass transformation temperature (high T_g) Plastic substrate (organic substrate) organic materials, such as FR-4.8, FR-5, BT, Driclad, Hitachi 679F... etc. The heat dissipating copper sheet 64 can be made of copper alloys such as C151 or C194, and the thickness is usually between 0.25 mm and 0.5 mm.

As shown in Figure 6, the surface of the two-layer plastic substrate 62 is provided with a plurality of bonding fingers 70 and ball pads 72, and a plurality of conductive lines 73 (only the part is drawn in Figure 5). The conductive circuit) is used to connect the wire bonding gold finger 70 and the solder ball pad 72. A copper wire layer 74 is provided on the other side of the plastic substrate 62. The plastic substrate 62 includes a plurality of circuit vias 76 for connecting the wire bonding gold fingers 70, the solder ball pad 72, the conductive circuit 73 and the copper wire layer 74. The surface of the plastic substrate 62 is coated with a green paint layer (solder mask) 78 to protect the package substrate 60, isolate the wire bonding gold finger 70 and the solder ball pad 72, and cover the conductive circuit 73. The surface of each contact 70 and 72 is plated with a nickel metal layer 80 and a pure gold metal layer 82 successively.

Two sides of the heat dissipating copper sheet 64 are respectively defined as a lamination side 84 and a heat dissipating surface 86. The plastic substrate 62 and the pressing surface 84 of the heat dissipating copper sheet 64 are bonded by a partially cured liquid adhesive layer 88, and the heat dissipating surface 86 of the heat dissipating copper sheet 64 is painted with a layer of black ink. 90. It is used to protect the heat dissipation copper sheet 64 and prevent the heat dissipation surface 86 of the heat dissipation copper sheet 64 from being continuously oxidized, corroded, or plated with a nickel metal layer and a pure gold metal layer. The thickness of the black ink layer 90 may be between 4 and 8 μm, and the thickness of the liquid glue layer 88 may be between 20 and 60 μm.

The material of the black ink layer 90 has high thermal conductivity and high product reliability requirements, such as the S-500 series black ink produced by Taiyo Ink. The thermal conductivity (generally represented by the letter "κ") of the black ink layer 90 itself is approximately in the range of 1 W/mK.

The material of the liquid glue layer 88 has a high conversion temperature (T_g), such as polyolefin, suitable T_gEpoxy resin, acrylic resin, Bismaleimide Triazine resin or BT resin and other viscous compounds. In order to avoid affecting the warpage of the package substrate 60, the elastic modulus of the viscous compound must be taken into consideration.

A black ink layer 92 is provided on the surface of the heat dissipating copper sheet 64 in the opening 66, and the thickness of the black ink layer 92 can be between 4 and 8 μm. The black ink layer 92 is used as a buffer layer between the epoxy resin (used to bond the IC chip 18) and the heat-dissipating copper 64, so that the IC chip 68 can be tightly attached to the heat-dissipating copper at high temperatures and after temperature cycles. On the sheet 64, a plurality of heat dissipation points 94 are provided in the black ink layer 92. The area ratio of the heat dissipation points 94 in the opening 66 can be between 0% and 90%, which is used to dissipate the heat generated by the IC chip 68. Conducted to the heat-dissipating copper sheet 64. The thermal conductivity of the black ink layer 92 itself is approximately in the range of 1 W/mK, and the heat generated by the IC chip 68 can also be quickly transferred to the heat sink 64. The heat sink 94, the wire gold finger 70 and the solder ball pad 72 are all formed at the same time to complete the formation of the nickel/pure gold layer, that is, the nickel metal layer 80 is formed on their surface first, and then the pure gold metal layer 82 is formed on the nickel metal layer 80 .

The manufacturing method of the package substrate 60 of the present invention is to first manufacture the plastic substrate 62 and the heat dissipation copper sheet 64 respectively, then apply the liquid glue layer 88 on the heat dissipation copper sheet 64 and subsequent heat treatment, and finally press the plastic substrate 62 and the heat dissipation copper sheet 64 combine together.

Please refer to FIGS. 7-9. FIGS. 7-9 are schematic diagrams of the manufacturing process of the plastic substrate 62 of the package substrate 60 of the present invention. As shown in Figure 7 (only a two-layer board is taken as an example), the present invention first uses two-layer or multi-layer PCB processes (two-layer or multi-layer PCB processes) on the plastic substrate 62 where the opening 66 has not yet been formed. The wire bonding gold finger 70, the solder ball bonding pad 72, the conductive circuit 73, the copper wire layer 74 and the circuit conduction 76 are fabricated. As shown in Fig. 8, a green paint layer 78 is then coated on the entire surface of the plastic substrate 62 on the same side as the wire gold finger 70 and the solder ball pad 72, and then a developing and etching process is used to form the green paint layer 78 picture of. Subsequently, an opening 66 is formed in the central portion of the plastic substrate 62 by means of a punching machine or mechanical routing (routing).

As shown in FIG. 9, after the opening 66 is formed, a single-sided or double-sided surface roughening process is performed to make the copper surface of the plastic substrate 62 rougher, so as to increase the adhesion between the plastic substrate 62 and the heat dissipation copper sheet 64. In the present invention, the surface drawing process forms an oxide layer 96 on the surface of the copper wire layer 74 of the plastic substrate 62, and the oxide layer 96 is composed of a black oxide layer or a brown oxide layer. After the surface roughening process, it is possible to choose whether to perform a heat treatment process on the plastic substrate 62. This selective heat treatment process is used to remove moisture in the plastic substrate 62 and slightly shrink the plastic substrate 62 so that after the subsequent high-temperature lamination process, the board of the package substrate 60 is warped (warpage). ) Get good control. This heat treatment process can also be omitted depending on the material of the plastic substrate, the subsequent manufacturing process and other factors.

Please refer to FIG. 10 to FIG. 13. FIG. 10 to FIG. 13 are schematic diagrams of the manufacturing process of the heat dissipating copper sheet 64 of the package substrate 60 of the present invention. When manufacturing the plastic substrate 62, the manufacturing work before pressing the heat dissipation copper sheet 64 can be performed at the same time. In order to facilitate the production of the heat-dissipating copper sheet 64, the present invention first drills a copper alloy sheet such as C151 or C194 to form a plurality of alignment holes (not shown) to provide alignment during subsequent printing or pressing. As shown in Fig. 10 and Fig. 11, the present invention uses the copper alloy sheet produced by the alignment hole to make the heat dissipation copper sheet 64. First, a double-sided surface roughening process is performed on the pressing surface of the heat dissipation copper sheet 64 An oxide layer 98 is formed on 84, and an oxide layer 100 is formed on the heat dissipation surface 86 of the heat dissipation copper sheet 64 at the same time. Both the oxide layer 98 and the oxide layer 100 are composed of a black oxide layer or a brown oxide layer, which are used to increase the adhesion on the surface of the heat-dissipating copper sheet 64.

As shown in FIG. 12, after the oxide layers 98 and 100 are formed, a double-sided black ink stencil printing process is performed to form a black ink layer 90 on the heat dissipation surface 86 of the heat dissipation copper sheet 64, respectively. , And a black ink layer 92 is formed in a predetermined area 102 of the pressing surface 84. The predetermined area 102 is predetermined for placing the IC chip 68, so the predetermined area 102 and the size and position of the opening 66 of the plastic substrate 62 correspond to each other. The black ink layer 92 may leave a plurality of cavities (that is, the cavities exposing the copper oxide layer) 104 in the predetermined area 102, which are prepared to form heat dissipation spots 94.

The black ink screen printing process uses a blank printing screen (not shown) to print the black ink layer 90. The mesh number of the printing screen is about 120~150/cm, while the black ink is printed. For the layer 92, another printing screen is used, and the position of the pattern on it is appropriately designed to ensure that the black ink layer 92 is only printed within the predetermined area 102. After the black ink screen printing process, a baking and curing process is performed, and the black ink layers 90 and 92 are cured by using an appropriate baking temperature and heating time.

As shown in Figure 13, after the black ink layers 90 and 92 are formed, a liquid glue layer printing process is then performed to print a viscous compound on the oxide layer 98 outside the predetermined area 102 of the heat sinking copper sheet 64 to form a liquidGlue layer88. Glue layer 88. If the thickness formed by only one printing is insufficient, a pre-baking can be performed and then the viscous compound can be printed again (or even the above steps are repeated several times) to make the liquid glue layer 88 reach an appropriate thickness. After that, another part of the curing process is carried out, using appropriate baking temperature and time to reduce the fluidity of the liquid glue layer 88 on the heat sinking copper sheet 64, so that the liquid glue layer 88 will not flow to heat dissipation during pressing. Within the predetermined area 102 of the copper sheet 64. After passing the inspection, the heat-dissipating copper sheet 64 is ready to be bonded to the plastic wire 62.

Please refer to FIG. 14, which is a schematic diagram of the high-temperature pressing process of the present invention. After the plastic substrate 62 shown in FIG. 9 and the heat dissipation copper sheet 64 shown in FIG. 13 are separately fabricated, a high-temperature pressing process is performed immediately, and the oxide layer 96 of the plastic substrate 62 is bonded to the heat dissipation copper sheet 64 by the liquid glue layer 88Pressing surface84on. The pressing surface 84. The pressure used in the high temperature pressing process is usually between 20~30 Kg/cm²The temperature used is usually between 150~200°C. After the high-temperature pressing process, a heat treatment process can be followed to make the liquid glue layer 88 more solidified and adjust the warpage of the package substrate 60. This heat treatment process can also be omitted, depending on the high temperature pressing process and other factors.

After the above-mentioned heat treatment process, a nickel/gold plating process is carried out. Each contact 70, 72 of the plastic substrate 62 and the cavity 104 of the heat dissipation copper sheet 64 are simultaneously plated with a nickel metal layer 80, and then the plastic substrate 62 A pure gold metal layer 82 is plated on the nickel metal layer 80 of the heat dissipating copper sheet 64 at the same time. The nickel/gold plating process can use the general electro-plating method or the chemical emersion method to form the nickel metal layer 80 and the pure gold metal layer 82, thus completing the package substrate shown in Figure 6 The production of 60.

In mass production of the package substrate 60, many CD-PBGA package substrates are produced on a substrate (not shown) at the same time. After the above process is completed on the substrate, a plurality of alignment holes can be formed in the unused part of the original substrate. The process of alignment holes can use X-ray tooling hole driller or general mechanical drilling machine. The drilling process of this alignment hole can also be omitted, depending on the original alignment hole design of the plastic substrate 62 and the heat sink 64 and other factors.

Then, a singulation process is used to cut the finished substrate into individual package substrates 60. In the present invention, it is also possible to directly cut out each package substrate 60 without having to drill the alignment hole first. The monolithic cutting process can use a general mechanical cutter (cutter), a mechanical router (router) or a saw (saw) capable of precise cutting. After the monolithic cutting process is completed, each package substrate 60 is cleaned and inspected to ensure that each package substrate 60 meets the industry standard specifications.

Please refer to FIG. 15, which is a schematic cross-sectional view of the present invention applied to a four-layer CD-PBGA package substrate. The appearance of the present invention applied to a four-layer CD-PBGA package substrate is shown in Figure 5, but the plastic substrate 62 also contains at least one copper wire layer 106 (in Figure 15 there are two inner copper wire layers 106). The structure of the heat-dissipating copper fins 64 has not changed. The copper wire layer 74, the copper wire layer 106 and the circuit conduction 76 of the plastic substrate 62 are properly connected, and can be used to connect the gold finger 70 of the plastic substrate 62 and the solder ball pad 72. When the manufacturing method of the present invention is applied to a four-layer CD-PBGA package substrate, the manufacturing process is the same except that the manufacturing process of the middle inner layer of the four-layer board needs to be increased.

The manufacturing method of the present invention is characterized in that a liquid glue layer 88 is used to bond the plastic substrate 62 and the heat dissipation copper sheet 64, and the black ink layer 90 and the black ink layer 92 are respectively used as the protective layer and buffer layer of the heat dissipation copper sheet 64, and The nickel/gold plating process of the contacts 70 and 72 is moved to after the high temperature pressing process. Therefore, the manufacturing method of the present invention has the following advantages:

First, after the nickel/gold plating process of the contacts 70 and 72 is moved to the high temperature pressing process, the contamination or damage of the surface of the pure gold metal layer 82 by other processes can be reduced or avoided.

Second, the thickness of the black ink layer 90 on the heat dissipation surface 86 of the heat dissipation copper sheet 64 is very thin (4~8μm), and the thermal conductivity (κ~1 W/mK) is also quite good, so the heat dissipation efficiency of the heat dissipation copper sheet 64 can be maintained . In addition, the black ink layer 92 on the pressing surface 84 of the heat dissipation copper sheet 64 acts as a buffer layer between the IC chip 68 and the heat dissipation copper sheet 64 to alleviate the problem of uneven thermal expansion between the two. Therefore, even at high temperatures and after temperature cycles , The IC chip 68 can still be tightly attached to the heat-dissipating copper sheet 64. The black ink layer 92 itself has excellent thermal conductivity, and is provided with many heat dissipation points 94, which can assist in transferring the high temperature generated by the IC chip 68 to the heat dissipation copper sheet 64.

Third, the production method of the present invention uses a printing method to form a protective black ink layer 90 on the heat dissipation copper sheet 64, instead of sticking tape or dry film on the other side of the heat dissipation copper sheet 64 (for single-sided nickel plating) , Can save production time and materials. In addition, the liquid glue layer 88 is also formed by printing, which can ensure that the adhesive compound is accurately coated in the area where the heat dissipation copper sheet 64 is joined.

Fourth, the manufacturing method of the present invention uses the liquid adhesive layer 88 to bond the plastic substrate 62 and the heat dissipation copper sheet 64, instead of using an adhesive film, and therefore does not need to form corresponding openings on the adhesive film, and the present invention completely saves The process of forming the precise opening 50 on the adhesive film 34 is difficult and expensive. In addition, the present invention utilizes a partial curing process to well control the amount of glue flowing in the liquid glue layer 88. During the high-temperature pressing process, the liquid glue layer 88 will not flow into the predetermined area 102 of the heat dissipation copper sheet 64. Therefore, there is no need to use any release film and packing layer in the high temperature pressing process. In other words, the use of the liquid glue layer 88 will greatly simplify the complexity and cost of the manufacturing process.

Fifth, to summarize the above four points, the greatest advantage of the present invention is that it can greatly simplify the complexity of the manufacturing process, greatly reduce the cost, and can maintain the efficacy and reliability of the product.

Compared with the conventional manufacturing method of the package substrate 10, the manufacturing method of the present invention uses a black ink layer 90 to be printed as a protective layer for the heat dissipation copper sheet 64. Therefore, the stress problem caused by the conventional nickel-plated protective layer 36, as well as the lengthy tape bonding and tearing problems in the manufacturing process, can be easily solved. In the present invention, a black ink layer 90 is formed in the opening 66 of the packaging substrate 60, which can improve the conventional epoxy resin (used to bond the IC chip 18) and the heat dissipation copper sheet 14 to withstand higher stress at high temperatures, and is not easy to be tightly bonded. Shortcomings. In addition, the present invention moves the nickel/gold plating process of the contacts 70 and 72 to the high temperature pressing process before proceeding, which reduces the chance of contamination or damage to the surface of the pure gold metal layer 82. Finally, the present invention uses the liquid glue layer 88 to bond the plastic substrate 62 and the heat dissipation copper sheet 64, without the conventional adhesive film 34, the release film 48, and the plugging layer 46, thereby greatly reducing the complexity of the process and reducing the production cost. .

The above are only the preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the scope of the patent application of the present invention shall fall within the scope of the patent of the present invention.

<p>60 Package substrate 62 Plastic substrate</p><p>64 Heat sink 66 openings</p><p>68 IC chip 70 wire gold finger</p><p>72 Solder ball pad 73 conductive circuit</p><p>74 Copper conductor layer 76 circuit conduction</p><p>78 Green paint layer 80 nickel metal layer</p><p>82 Pure gold metal layer 84 pressing surface</p><p>86 Cooling surface 88 liquid glue layer</p><p>90 Black ink layer 92 Black ink layer</p><p>94 Heat dissipation point 96 oxide layer</p><p>98 Oxide layer 100 Oxide layer</p><p>102 Scheduled area 104 void</p><p>106 Copper conductor layer</p>

FIG. 1 is a schematic diagram of a conventional downwardly opening plastic ball grid array package substrate.

FIG. 2 is a schematic cross-sectional view of the package substrate in FIG. 1 (a two-layer package substrate is taken as an example).

FIG. 3 is a schematic diagram of stacking in the high-temperature pressing process of the manufacturing method of the conventional packaging substrate.

FIG. 4 is a schematic diagram of removing the release film and the packing layer after the conventional high-temperature pressing process.

FIG. 5 is a schematic diagram of a plastic ball grid array package substrate opening downward in the present invention.

FIG. 6 is a schematic cross-sectional view of the package substrate in FIG. 5 (a two-layer board package substrate is taken as an example).

Figures 7-9 are schematic diagrams of the manufacturing process of the plastic substrate of the packaging substrate of the present invention.

FIG. 10 to FIG. 13 are schematic diagrams of the manufacturing process of the heat sink copper sheet of the package substrate of the present invention.

Figure 14 is a schematic diagram of the high-temperature pressing process in the present invention.

15 is a schematic cross-sectional view of the application of the present invention to a four-layer CD-PBGA package substrate.