Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2001-04-25
2004-04-20
Pert, Evan (Department: 2827)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S764000
Reexamination Certificate
active
06724638
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a printed board for mounting thereon electronic components such as an IC chip and armethod of manufacturing the printed board. More particularly, the present invention relates to a printed circuit board including therein a capacitor or the like and a method of manufacturing the printed circuit board.
BACKGROUND ART
At present, for the purpose of smoothly supplying electric power to an IC chip, a chip capacitor is often mounted on the surface of a printed circuit board used as a package substrate.
The reactance of a wiring from the chip capacitor to the IC chip depends on frequency. Due to this, as IC chip driving frequency increases, the chip capacitor cannot exhibit sufficient effect even if the chip capacitor is mounted on the surface of the printed circuit board. Considering this, the applicant of the present invention proposed a technique, identified as Japanese Patent Application No. 11-248311, for forming a concave portion on a core substrate so as to contain therein a chip capacitor. Techniques for embedding a capacitor in a substrate are disclosed in Japanese Patent Unexarnined Application Publication (to be referred to as “Publication” hereinafter) Nos. 6-326472, 7-263619, 10-256429, 11-45955, 11-126978, 11-312868 and the like.
Publication No. 6-326472 discloses a technique for embedding a capacitor in a resin substrate made of glass epoxy. With this constitution, it is possible to reduce power supply noise and to dispense with a space for mounting the chip capacitor, thereby making an insulating substrate small in size. Publication No.7-263619 discloses a technique for embedding a capacitor in a substrate made of ceramic, alumina or the like. With this constitution, the capacitor is connected between a power supply layer and a ground layer to thereby shorten wiring length and reduce wiring inductance.
However, according to the Publication Nos. 6-326472 and 7-263619 stated above, the distance from the IC chip to the capacitor cannot be set too short and the wiring inductance cannot be reduced as currently desired in the higher frequency region of the IC chip. In case of a multi-layer buildup wiring board made of resin, in particular, due to the difference in the coefficient of thermal expansion and a capacitor made of ceramic and a core substrate as well as interlayer resin insulating layers made of resin, disconnection occurs between the terminal of the chip capacitor and a via, separation occurs between the chip capacitor and the interlayer resin insulating layers and cracks occur to the interlayer resin insulating layers. Thus, the multi-layer buildup wiring board could not realize high reliability for a long time.
On the other hand, according to the invention of Publication No. 11-248311, if the position at which a capacitor is arranged is deviated, the connection between the terminal of the capacitor and a via cannot be accurately established and power cannot be possibly supplied from the capacitor to the IC chip.
The present invention has been made to solve the above-stated problems. It is, therefore, an object of the present invention to provide a printed circuit board including therein a capacitor and having enhanced connection reliability and to provide a method of manufacturing the printed circuit board.
DISCLOSURE OF THE INVENTION
In order to achieve the above purpose, according to claim
1
, aprinted circuit board constituted by alternately laminating interlayer resin insulating layers and conductive circuits in a multilayer manner on a core substrate containing a capacitor, characterized in that
the core substrate containing said capacitor is constituted by providing a first resin substrate, a second resin substrate having an opening for containing the capacitor and a third resin substrate in a multilayer manner while interposing bonding plates.
According to claim
16
, a printed circuit board manufacturing method characterized by comprising at least the following steps (a) to (d):
(a) formingaconductor pad section ona first resin substrate;
(b) connecting a capacitor to said conductor pad section of said first resin substrate through a conductive bonding agent;
(c) providing a third resin substrate, a second resin substrate having an opening for containing said capacitor and said first resin substrate in a multilayer manner while interposing bonding plates so that said capacitor of said first resin substrate is contained in said opening of said second resin substrate and that said opening of said second resin substrate is closed by the third resin substrate; and
(d) heating and pressurizing said first resin substrate, said second resin substrate and said third resin substrate, to thereby provide a core substrate.
According to a printed circuit board recited in claim
1
and a printed circuit board manufacturing method recited in claim
16
, the capacitor can be contained in the core substrate and the distance between the IC chip and the capacitor is shortened. Therefore, it is possible to reduce the loop inductance of the printed circuit board. Further, since the core substrate is constituted by providing resin substrates in a multilayer manner, it can obtain sufficient strength. Besides, since the core substrate is constituted smoothly by providing the first resin substrate and the third resin substrate on the both sides of the core substrate, respectively, it is possible to appropriately form interlayer resin insulating layers and conductor circuits on the core substrate and to thereby decrease the probability of the occurrence of defective printed circuit boards.
Interlayer resin insulating layers are provided on the core substrate, via holes or through holes are provided in the interlayer resin insulating layers, and conductor circuits serving as conductive layers are formed, which means the circuit is formed by a buildup method. As the buildup method, either a semi-additive method, a full additive method can be employed.
It is preferable that a gap is filled with a resin. By removing the gap between the capacitor and the core substrate, the capacitor included in the core substrate behaves less frequently. Even if a stress resulting from the capacitor occurs, the stress can be eased by the filled resin. Also, the resin can advantageously bond the capacitor to the core substrate and prevent migration.
According to claim
2
, each of the bonding plates has a core impregnated with a thermosetting resin. Due to this, the core substrate can obtain high strength.
According to claim
3
, each of the first, second and third resin substrates has a core impregnated with a resin. Due to this, the core substrate can obtain high strength.
According to claim
4
, a plurality of capacitors are contained in the core substrate. Due to this, it is possible to highly integrate the capacitors.
According to claim
5
, the conductor circuits are formed on the second resin substrate. Due to this, it is possible to increase the wiring density of the substrate and to reduce the number of interlayer resin insulating layers.
According to claim
6
, the capacitor is contained in the substrate and, at the same time, a capacitor is provided on the surface of the printed circuit board. Since the capacitor is contained in the printed circuit board, the distance between the IC chip and the capacitor is shortened, loop inductance is reduced and power can be supplied momentarily. Since the capacitor is also provided on the surface of the printed circuit board, a mass storage capacitor can be attached and high power can be easily supplied to the IC chip.
According to claim
7
, the capacitance of the capacitor on the surface is equal to or higher than that of a capacitor on an inner layer. Due to this, it is possible to ensure the desired operation of the IC chip without lack of power supply in a high frequency region.
According to claim
8
, the inductance of the capacitor on the surface is equal to or higher than that of the capacitor on an inner layer. Due to this, it is possible to ensure the desired operation of the IC chip without
Asai Motoo
Inagaki Yasushi
Shirai Seiji
Wang Dongdong
Yabashi Hideo
Dinh Tuan
Ibiden Co. Ltd.
Pert Evan
Pillsbury & Winthrop LLP
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