Method of manufacturing an integrated circuit

Details Method of manufacturing an integrated circuit Method of manufacturing an integrated circuit

1999-01-08

2001-10-02

Arbes, Carl J. (Department: 3729)

Metal working

Method of mechanical manufacture

Electrical device making

C029S840000, C029S740000

Reexamination Certificate

active

06295727

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Taiwan application serial no. 87114256, filed Aug. 28, 1998, the full disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a real time clock integrated circuit (RTC IC), and more particularly to an integrated real-time clock integrated circuit device including a RTC and its related components and a method for manufacturing the same.
a device and method to integrate the RTC IC with its related components in a single package.
2. Description of the Related Art
Electrical appliances are widely used in the world. There is no exaggeration to say that these electrical appliances which provide great convenience to the human being are indispensable to the day-to-day life in this modern society.
One of the salient features of the electrical appliances is that most of them require a clocking function. For example, a clock circuit is required to automatically turn on and off a Hi-Fi or VCR. Also, commonly used personal computers are all embedded with a clock circuit, which operates to provide an accurate time even the main power of the computer is turned off. The operating system of the computer system can attach time information to a file when it is created or altered based on the clock function provided. Users can also distinguish the old files from the new ones according to the associated time stamp.
FIG. 1
is a circuit diagram of a clock circuit
100
, including a real time clock integrated circuit (RTC IC)
110
, a battery
134
and an oscillating circuit consisting of a quartz oscillator
131
and capacitors
132
,
133
. External control circuit, for example, a central processing unit (CPU) of a personal computer, can set parameters for the RTC IC
110
or read time information through a line
120
. Note that the RTC IC
110
needs to keep operating to provide timing functions when the external power source is turned off. Therefore, the battery
134
is required to provide power for the RTC IC
110
. The battery
134
can be a button-type lithium battery with a voltage of 3.0 V and a capacity of 50 mAH. The RTC IC
110
requires only a very small current to maintain operation thanks to the advancements in semiconductor technology. Therefore, the above-mentioned lithium battery can provide power to the RTC IC
100
for as long as two years. The quartz oscillator
131
provides a time base for the RTC IC
110
. The capacitors
132
and
133
together with the quartz oscillator
131
constitute an oscillating circuit.
Although semiconductor technology has made significant progress recent years, the quartz oscillator and battery are nevertheless not integrated in the RTC IC
100
. Furthermore, the capacitors
132
and
133
in the clock circuit
100
of
FIG. 1
are closely related to the oscillating circuit based on the quartz oscillator
131
, and therefore not integrated in the RTC IC
100
either. It is then inevitable to include the battery
134
, quartz oscillator
131
, and capacitors
132
and
133
in the clock circuit
100
when the RTC IC
100
is used.
In manufacturing the clock circuit
100
, all the components, including the RTC IC
110
, the battery
134
, and quartz oscillator
131
, require a manual assembly with an exception of the capacitors
132
and
133
, which can be assembled automatically by using a surface mounted device (SMD) technology. The manual assembly of these components significantly increases the manufacturing cost. In addition, the installation of the battery
134
requires a battery holder, which also increases the manufacturing cost. Furthermore, when the assembling process is completed, an examination process is required to make sure the battery voltage is normal and the oscillating frequency is correct. If there is any abnormality occurred, a fix-up process is performed until everything is in normal condition. These extra examination and fix-up processes inevitably increase the manufacturing cost.
As a summary, the above-mentioned clock circuit using the RTC IC, quartz oscillator, capacitors, and battery has the following disadvantages:
1. The battery, quartz oscillator, and capacitors are not integrated with the RTC IC. Therefore, a large layout area on a printed circuit board (PCB) is required. Also, an extra battery holder is required in addition to a manual assembly to install the battery and the quartz oscillator, which increase manufacturing cost for the clock circuit.
2. When the clock circuit is assembled, extra examination and fix-up processes are required to make sure the battery voltage is normal and the generated signal frequency is correct. If there is any abnormality found during the examination process, further adjustment or repair need to be performed by engineers until the circuit is in normal condition. The involved examination and fix-up processes increase manufacturing cost as well.
SUMMARY OF THE INVENTION
It is therefore an objective of the present invention to provide a device and method for manufacturing an integrated RTC IC package, which integrate the RTC IC and its related components in a single package. Therefore, the layout area required by the cock circuit is significantly reduced. Furthermore, only a single manual assembling process is required to manufacture the integrated RTC IC package. Also, various examination steps are built into every process to manufacture the integrated RTC IC package to make sure the completed products are in normal condition. No extra examination and fix-up processes are required for the completed products so that manufacturing cost can be significantly reduced.
It is another objective of the present invention to provide a packaging cover having an appropriate supporting mechanism and directional marks corresponding to the RTC IC both inside and outside the packaging cover to facilitate the mounting of the RTC IC in the packaging cover. Also, users can easily identify the direction of the assembled RTC IC package with the help of the directional marks. Furthermore, the packaging cover is manufactured using a material of higher durability without producing scratches on the surface of the packaging cover.
In accordance with the foregoing and other objectives of the present invention, an integrated RTC IC package is provided, which includes a printed circuit board (PCB), a first capacitor, a second capacitor, a quartz oscillator, a battery, a packaging cover, and a RTC IC. The first capacitor, the second capacitor, and the quartz oscillator are soldered on the PCB. A plurality of pins of the RTC IC are lifted and bent upward before the IC pins are rectified. The PCB soldered with related components and the rectified RTC IC are soldered together. Positive and negative electrodes of the battery are soldered respectively to produce soldering points before soldering on the PCB.
The packaging cover is filled with an appropriate amount of gluing material. Subsequently, the RTC IC is mounted in the packaging cover to produce the integrated RTC IC package.
According to a preferred embodiment of the present invention, the battery is a button-type lithium battery.
Accordingly, a method for manufacture an integrated RTC IC package is provided, comprising the steps of:
providing a printed circuit board (PCB);
providing at least one capacitor soldered on the PCB;
providing a quartz oscillator soldered on the PCB;
examining soldering points to identify defective soldering points;
reworking the defective soldering points until the defective soldering points pass the examination;
providing a real time clock integrated circuit (RTC IC), wherein a plurality of pins of the RTC IC are bent upward and pins of the RTC IC are rectified;
soldering the PCB on a surface of the RTC IC;
providing a battery soldered on the PCB;
examining soldering points and measuring a battery voltage;
re-soldering the soldering points if the soldering points fail to pass the examination;
replacing the battery if the battery voltage is abnormal;
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