The present invention relates to a method for forming a slot on a substrate and a structure thereof, and more particularly to a method for forming a slot on a substrate and a structure of the substrate having the slot formed by a two-step process.
Traditionally, a substrate, such as a substrate of a BOC (Board-On-Chip) package, can be processed to form a slot by a milling cutter (i.e. a boring tool). However, a cutting process utilizing the milling cutter may cause some problems. For example, the yield of the substrate (per unit time) is relatively low; the manufacture cost of the substrate is relatively high; the slot on the substrate may be formed with metal burrs, and etc. Alternatively, the slot can be formed by one-step punching. However, the substrate with the slot formed by punching still has some disadvantages. For example, glass fiber layers of the substrate is easily peeled off; a metal trace layer (golden fingers) on the substrate is easily peeled off; the glass fiber layers may be exposed in the slot to form burrs; the manufacture cost of punching molds is relatively high, and etc.
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As a result, it is necessary to develop a technological solution to solve the foregoing problems existing in the traditional method for forming the slot 12 of the substrate 10.
A primary object of the present invention is to provide a method for forming a slot on a substrate and a structure of the substrate having the slot, wherein the substrate is formed with the slot by a two-step process, so as to enhance the product quality of the substrate and lower the manufacture cost thereof.
To achieve the above object, the method for forming a slot on a substrate according to a preferred embodiment of the present invention comprises steps of:
providing a substrate having a plurality of metal pads which are arranged into at least one row;
forming two circular holes on a predetermined cut area of the substrate by two hole manufacturing devices, wherein the two circular holes are formed adjacent to two outermost metal pads of the at least one row of the metal pads, respectively; and
forming a rectangular hole between the two circular holes on the substrate by punching, wherein the rectangular hole has two ends overlapped with the two circular holes, respectively, so as to form a slot on the substrate.
In an embodiment of the present invention, the step of forming the two circular holes can be carried out by a milling process (i.e. a boring process) or a punching process. If the step is carried out by the milling process, the hole manufacturing devices can be selected from milling cutters (i.e. boring tools). Alternatively, if the step is carried out by the punching process, the hole manufacturing devices can be selected from circular punches.
In an embodiment of the present invention, the rectangular hole has a width slightly smaller than a diameter of the two circular holes, so as to lower the friction between a punch and the substrate.
In an embodiment of the present invention, the step of forming the rectangular hole by punching further comprises a step of: injecting a high-pressure gas to press the metal pads when a punch for the punching process is elevated, so as to prevent the metal pads from being peeled off.
In an embodiment of the present invention, the metal pads are arranged into two rows corresponding to each other.
In an embodiment of the present invention, the substrate having the slot comprises a slot including two circular holes and a rectangular hole. The substrate has a plurality of metal pads which are arranged around the slot. The two circular holes are formed on two ends of the slot, respectively, and selectively processed by a milling process or a punching process. The rectangular hole processed by another punching process is formed between the two circular holes, and overlapped with the two circular holes. Furthermore, the rectangular hole has a width slightly smaller than a diameter of the two circular holes, so as to lower the friction between a punch and the substrate during punching. The metal pads on the substrate are selectively arranged into two rows corresponding to each other. The rectangular hole is surrounded by the two rows of the metal pads and the two circular holes.
In comparison with prior art, a method for forming a slot on a substrate and a structure of the substrate having the slot according to a preferred embodiment of the present invention provides a two-step process used to firstly form two circular holes on two ends of the predetermined cut area and then form a rectangular hole between the two circular holes by punching, so as to be advantageous to lower the friction generated between a punching machine and the substrate during punching, prevent the glass fiber layers from being peeled off, avoid the glass fiber layers from forming burrs, and prevent the metal trace layer (i.e. metal pads) from being peeled off. Meanwhile, because a portion of the substrate having the metal trace layer is not processed by a milling process, it can prevent the metal trace layer from forming metal burrs. As a result, according to the method of the present invention, the yield of the substrate (per unit time) and the product quality thereof can be increased, while it is unnecessary to process the substrate by an expensive optical projection grinder and related mold equipments, so as to lower the manufacture cost of the substrate.
The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein
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As described above, in comparison with prior art, a method for forming a slot on a substrate and a structure of the substrate having the slot according to a preferred embodiment of the present invention provide a two-step process used to firstly form the two circular holes 22 on two ends of the predetermined cut area 23 and then form the rectangular hole 42 between the two circular holes 22 by punching, so as to be advantageous to lower the friction generated between the punching machines and the substrate 20 during punching, prevent the glass fiber layers from being peeled off, avoid the glass fiber layers from forming burrs, and prevent the metal trace layer (i.e. the metal pads 24) from being peeled off. Meanwhile, because a portion of the substrate 20 having the metal trace layer is not processed by a milling process, it can prevent the metal trace layer from forming metal burrs. As a result, according to the method of the present invention, the yield of the substrate 20 (per unit time) and the product quality thereof can be increased, while it is unnecessary to process the substrate 20 by an expensive optical projection grinder and related mold equipments, so as to lower the manufacture cost of the substrate 20.
The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications to the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.
Number | Date | Country | Kind |
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096115159 | Apr 2007 | TW | national |