RESCUE STRUCTURE AND METHOD FOR LASER WELDING
A rescue structure to repair an open wire includes a first metal layer having at least a rescue line, an isolation layer formed on the first metal layer, and a second metal layer formed on the isolation layer. The second metal layer has at least a signal line crossing the rescue line to form an enlarged intersection node. The intersection node is particularly arranged far from the side where the rescue line is used for signal transmission.
This application is a Divisional of co-pending application Ser. No. 11/607,874, filed on Dec. 4, 2006, the entire contents of which are hereby incorporated by reference and for which priority is claimed under 35 U.S.C. §120. This nonprovisional application also claims priority under 35 U.S.C. §119(a) on Patent Application No. 095116460 filed in Taiwan on May 9, 2006, the entirety of which is herein incorporated by reference.
BACKGROUND OF THE INVENTION(1) Field of the Invention
The invention relates to a rescue structure and a method for laser welding, and more particularly to the one that can improve the rescue quality by simplifying the needed rescue process.
(2) Description of the Prior Art
It is well known that the display area of the liquid crystal display (LCD) is formed by crossing a plurality of data lines with a plurality of gate lines. A pixel of the display area is the square area defined by two adjacent data lines and two adjacent gate lines. By providing transistors internally to the pixels and by controlling illumination of the transistors, a predetermined image can thus be displayed.
Referring now to
Empirically, in the manufacturing process of the signal lines 2, possible particle contamination to break the line is also possible, as area C shown in
In the art, to repair contamination in the signal lines, some rescue lines are usually included in the LCD 1, such as rescue lines R1 and R2 in
For example, in the case that point P of the signal line 2 is a broken point and needs to be repaired, a typical repair is to engage by laser welding (1) the signal line 2 at area A with the rescue line R1 and (2) the signal line 2 of area B with the rescue line R1, and then signals of the driver IC 3 can be transmitted to the lower-P area of the line 2 via the rescue line R1. Upon such an arrangement, the display at pixels in the lower-P area of the line 2 can be resolved and thus the display quality of the LCD can be greatly improved. Note that the only defect pixel now is the pixel at point P.
Referring now to
As noted in the art, laser welding and laser cutting are repeated again and again to process the conventional laser rescue. In addition, while in manual laser welding, the welding pad is made broader to ease the manual laser operation. Yet, the increase of the RC value is the trade-off. As a consequence of the aforesaid laser rescue, the signal realization is substantially lowered and the yield of the rescue is also reduced.
Therefore, an improved laser rescue method to increase the rescue yield without sacrificing the RC value is needed.
SUMMARY OF THE INVENTIONAccordingly, it is an object of the present invention to provide a laser rescue structure that won't increase its RC value after a laser rescue welding.
It is an another objective of the present invention to provide a laser rescue method that can simplify the laser rescue process.
In the present invention, the laser rescue structure includes a first metal layer having at least a rescue line, an isolation layer laminated upon the first metal layer, a second metal layer laminated upon the isolation layer. The second metal layer includes at least a signal line crossing spatially with the rescue line of the first metal layer. In the crossing area, an enlarged intersection node is formed at one side of the rescue line, in which the side does not transmit any signals.
The laser rescue structure of the present invention is constructed in the LCD having at least a driver IC connected electrically with one end of the signal line, while another end of the signal line is connected to an electrostatic discharge (ESD) device. In the present invention, the signal line can be a data line connected electrically to a drain of a thin film transistor (TFT) of the LCD. In the present invention, the signal line can also be a gate line connected electrically to a gate of the TFT.
In the present invention, the laser rescue method comprises a step of forming a first metal layer having at least a rescue line, a step of laminating an isolation layer on the first metal layer, a step of laminating a second metal layer on the isolation layer on which at least a signal line is formed by crossing spatially with the rescue line and further in which an enlarged intersection node is formed aside an intersection area of the signal line and the rescue line, and a step of laser welding to cut the rescue line at the intersection node and to connect metally the intersection node with the rescue line at the intersection area. In the present invention, the aforesaid side of the intersection area does not bear any signal transmission.
In the present invention, the intersection node of the laser rescue structure is formed to one side of the signal line. Compared to the conventional welding pad, the intersection node can be made smaller, the RC value thereof can be less affected by the laser welding, and thus the signal realization can be substantially maintained.
Further, the laser rescue method of the present invention is featured in processing the laser welding and cutting only at the intersection node of the signal line, such that one laser step can complete the rescue operation. Therefore, the laser rescue method of the present invention can be successfully simplified.
All these objects are achieved by the rescue structure and method for laser welding described below.
The present invention will now be specified with reference to its preferred embodiment illustrated in the drawings, in which:
The invention disclosed herein is directed to a rescue structure and a rescue method for laser welding. In the following description, numerous details are set forth in order to provide a thorough understanding of the present invention. It will be appreciated by one skilled in the art that variations of these specific details are possible while still achieving the results of the present invention. In other instance, well-known components are not described in detail in order not to unnecessarily obscure the present invention.
Referring now to
As shown in
As shown in
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The rescue structure in
Referring now to
Similarly, the laser welding available for the aforesaid rescue method can be performed by firstly removing the isolation layer with a low-power laser and secondly welding the intersection node and the rescue line with a high-power laser. Alternatively, the laser welding can be properly arranged to remove the isolation layer and weld the intersection node and the rescue line at a single operation by a proper-power laser.
In the foregoing description, the rescue line and the signal line are crossed spatially. To a structure that the rescue line and the signal line are parallel and overlapping, the rescue structure and method can be modified as follows.
Referring now to
Referring now to
While the present invention has been particularly shown and described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be without departing from the spirit and scope of the present invention.
Claims
1. A laser rescue method, comprising steps of:
- forming a first metal layer on a substrate;
- laminating an isolation layer on said first metal layer;
- laminating a second metal layer on said isolation layer;
- laser welding to form a through slit in said second metal layer, said isolation layer and said first metal layer to expose a part of upper surface of said substrate, wherein said second metal layer, said isolation layer and said first metal layer all be divided into only two separated parts respectively; and
- laser welding a portion of said second metal layer to let the melting portion of said second metal layer flow along a sidewall of the through slit to contact with said first metal layer.
2. The laser rescue method according to claim 1, wherein the step of forming said first metal layer on said substrate is forming said first metal layer on a glass substrate.
3. The laser rescue method according to claim 1, wherein the step of laser welding to form said through slit in said second metal layer, said isolation layer and said first metal layer is performed with a low-power laser.
4. The laser rescue method according to claim 1, wherein after the step of forming said through slit in said second metal layer, said isolation layer and said first metal layer, there is no signal transmission between said two separated parts of said second metal layer and said first metal layer respectively.
Type: Application
Filed: Sep 29, 2009
Publication Date: Jan 21, 2010
Inventors: Chu-Yu LIU (Hsin-Chu), Shyh-Feng CHEN (Hsin-Chu), Wen-Bin CHEN (Hsin-Chu)
Application Number: 12/569,029
International Classification: H01L 21/82 (20060101);