Circuit board composite target

Abstract

The utility model discloses a circuit board composite target, comprising a first circuit layer provided with a first blind hole which is a round hole; the second circuit layer is arranged above the first circuit layer, a second blind hole and a third blind hole are formed in the second circuit layer, the third blind hole is formed in the middle of the second blind hole, the second blind hole is an annular hole, and the third blind hole corresponds to the first blind hole in the vertical direction; wherein the circle center of the first blind hole, the circle center of the third blind hole and the circle center of the second blind hole are overlapped, so that the laser drilling and the pattern exposure alignment reference are completely consistent, the alignment effect can stably reach within 2 mil, meanwhile, four targets are reduced on a plate, the space is saved, the processing time is shortened, and the production efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of PCB, in particular to a composite target for a circuit board. Background Art

[0002] Arbitrary-layer high-density interconnect (HDI) PCB (Printed Circuit Board) products require consistent alignment between laser drilling and pattern exposure during processing. The laser hole ring has been reduced from 3mil to 4mil in the industry's single-sided design to less than 2.5mil. In order to reduce the functional test and customer-mounted component deviation caused by blind hole damage, it is necessary to design the alignment target for laser drilling and pattern ablation more accurately.

[0003] In the original processing, the laser drilling machine first grabs the through hole target to process a 0.5mm alignment target, and then grabs the 0.5mm target to process a 2.5mm alignment target used for blind holes and graphic exposure. Through experimental analysis and mass production verification, the smaller the distance between the two targets, the better the position consistency between the blind holes and the graphics.

[0004] However, there is always a position difference between the two sets of alignment targets, and the alignment of the blind hole and its corresponding graphic hole ring cannot be stably achieved within 2.5 mil. The processing of the two sets of targets takes a long time and occupies space, which is not conducive to improving production efficiency. Utility Model Content

[0005] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a composite target for a circuit board, which ensures that the alignment reference of laser drilling and pattern exposure is completely consistent by aligning the centers of the first blind hole and the second blind hole, thereby improving production efficiency.

[0006] According to the embodiment of the utility model, the circuit board composite target includes: a first circuit layer, a first blind hole is arranged on the first circuit layer, and the first blind hole is a circular hole; a second circuit layer, the second circuit layer is arranged above the first circuit layer, and a second blind hole and a third blind hole are arranged on the second circuit layer, the third blind hole is arranged in the middle of the second blind hole, the second blind hole is a circular hole, and the third blind hole corresponds to the first blind hole in the up and down direction; wherein the center of the first blind hole, the center of the third blind hole and the center of the second blind hole overlap.

[0007] According to the composite target for the circuit board of the embodiment of the utility model, by making the centers of the first blind hole and the second blind hole coincide, it is ensured that the laser drilling and the pattern exposure alignment references are completely consistent, and the alignment effect can be stably achieved within 2 mil. At the same time, 4 targets are reduced on the board, which not only saves space but also reduces processing time and improves production efficiency.

[0008] According to some embodiments of the present invention, the diameter of the first blind hole is greater than the diameter of the third blind hole.

[0009] According to some embodiments of the present invention, the diameter of the first blind hole is d1, the diameter of the third blind hole is d2, and d1 and d2 respectively satisfy the relationship: 0.6mm≤d1≤1.1mm, 0.2mm≤d2≤1.0mm.

[0010] According to some embodiments of the present invention, the inner diameter of the second blind hole is d3 and the outer diameter is d4, and d3 and d4 respectively satisfy the relationship: 1.1mm≤d3≤2.4mm, 2.4mm≤d4≤4mm.

[0011] According to some embodiments of the present invention, the circuit board composite target further includes: a third circuit layer, the third circuit layer is arranged above the second circuit layer, a fourth blind hole is arranged on the third circuit layer, and the fourth blind hole covers the second blind hole and the third blind hole.

[0012] According to some embodiments of the present invention, the fourth blind hole is rectangular or circular.

[0013] According to some embodiments of the present invention, the circuit board composite target further includes: a fourth circuit layer, the fourth circuit layer is arranged below the first circuit layer, and the fourth circuit layer is an unetched circuit board.

[0014] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0016] Figure 1 is a schematic diagram of a second circuit layer according to an embodiment of the utility model;

[0017] Figure 2 is a schematic diagram of a first circuit layer according to an embodiment of the utility model;

[0018] Figure 3 is a schematic diagram of a fourth circuit layer according to an embodiment of the utility model;

[0019] Figure 4 is a schematic diagram of a circuit board composite target according to an embodiment of the utility model;

[0020] Figure 5It is a cross-sectional view of the design of the composite target of the circuit board according to the embodiment of the utility model.

[0021] Reference numerals:

[0022] 100. Circuit board composite target;

[0023] 10. First circuit layer; 11. First blind hole;

[0024] 20. Second circuit layer; 21. Second blind hole; 22. Third blind hole;

[0025] 30. The third circuit layer; 31. The fourth blind hole;

[0026] 40. The fourth circuit layer. DETAILED DESCRIPTION

[0027] The embodiments of the present utility model are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present utility model are described in detail below.

[0028] Reference below Figure 1-Figure 5 A circuit board composite target 100 according to an embodiment of the present invention is described.

[0029] Arbitrary layer high density interconnect (HDI) PCB (Printed Circuit Board) products are usually composed of multiple layers of circuit boards. Each layer has an independent circuit function. It is generally made of materials such as copper foil, substrate, prepreg and ink. A firm physical connection is formed between the layers by lamination.

[0030] Copper foil is used to draw circuit diagrams. The core board is a double-sided copper-clad board and the skeleton of the circuit board. It is composed of a substrate and copper foil. The prepreg is the adhesive between the core boards and also serves as an insulator. The ink can serve as a soldering iron, insulation, corrosion protection or marking function.

[0031] During the PCB manufacturing process, in order to ensure that the PCB has a high degree of precision and achieve the purpose of external alignment, some specific graphics or marks are usually added to the circuit board. These graphics or marks are called alignment marks or alignment graphics. The alignment graphics can be added to the PCB by printing or other methods, for example, using ink for marking. The alignment graphics usually exist at the same time as the circuit pattern and do not affect the function of the circuit.

[0032] Also, in the PCB manufacturing process, in order to connect the multi-layer circuit boards, the connection channels between the circuit boards can be opened by drilling. Laser drilling is a method of hole processing using laser technology, which can form tiny, precise perforations that penetrate up and down on the PCB. During the laser drilling process, to ensure that the laser beam is accurately irradiated to the required position, some special targets are usually added to the surface or inside of the PCB to provide an accurate reference point for the laser processing system to ensure that the laser performs the drilling operation in the correct position, that is, laser drilling alignment.

[0033] Similarly, graphic exposure refers to the use of photosensitive materials to make circuit board patterns during the PCB manufacturing process. This process involves using a light source to expose the PCB material, causing the photosensitive material to undergo chemical changes to form the desired circuit pattern. The graphic exposure machine also needs to perform graphic exposure operations after identifying the target on the circuit board.

[0034] Among them, the camera on the machine is used to identify and locate the target during the laser drilling alignment and graphic exposure alignment processes.

[0035] It should also be noted that target burning usually refers to a method of forming holes by heat treatment or laser etching, and laser etching is used in the embodiment of the utility model. The target burning hole is a key element for ensuring the correct alignment and positioning between different layers of the PCB and between different manufacturing stages, and can provide an accurate reference point to ensure that each part is correctly aligned.

[0036] Reference Figure 1 , Figure 2 and Figure 5 As shown, the circuit board composite target 100 according to the embodiment of the utility model includes: a first circuit layer 10 and a second circuit layer 20 .

[0037] The first circuit layer 10 is provided with a first blind hole 11, which is a circular hole. The second circuit layer 20 is provided above the first circuit layer 10. The second circuit layer 20 is provided with a second blind hole 21 and a third blind hole 22, which is provided in the middle of the second blind hole 21. The second blind hole 21 is a circular hole. The third blind hole 22 corresponds to the first blind hole 11 in the up and down direction, wherein the center of the first blind hole 11, the center of the third blind hole 22 and the center of the second blind hole 21 overlap.

[0038] Specifically, there are four circuit layers in the PCB of the embodiment of the utility model. The first circuit layer 10 is the third circuit layer. The second circuit layer 20 is located above the first circuit layer 10 and is the second circuit layer. The first circuit layer 10 is provided with a first blind hole 11. The first blind hole can use exposure etching to remove part of the copper foil on the first circuit layer 10 to form a copper-free area.

[0039] Similarly, the second blind hole 21 and the third blind hole 22 on the second circuit layer 20 can use exposure etching to remove part of the copper foil on the first circuit layer 10 to form a copper-free area, which can prevent the accuracy requirements of the pattern exposure alignment and the laser drilling alignment from being affected, and ensure the integrity of the bottom layer alignment points corresponding to the target pattern.

[0040] Among them, the second blind hole 21 is a circular hole, the third blind hole 22 is a circular hole and is located in the middle of the second blind hole 21, the center of the first blind hole, the center of the third blind hole 22 and the center of the second blind hole 21 overlap, the third blind hole 22 is an alignment target for laser drilling, and the second blind hole 21 is an alignment target for pattern exposure. The two are designed as concentric circles, which can reduce the processing procedures of laser drilling from the original 8 laser drilling alignment targets and pattern exposure alignment targets to 4 targets, which greatly improves the on-site processing efficiency and the equipment alignment accuracy capability, so that the on-site laser drilling ring width is increased from the original single-side 3mil to single-side 2mil, which greatly optimizes the existing process capabilities.

[0041] Moreover, with the increase of laser drilling ring width, the difficulty of engineering photolithography design is also reduced, which effectively improves the efficiency of engineering production and thus enhances the competitiveness of products.

[0042] Therefore, by making the center of the third blind hole 22 coincide with the center of the second blind hole 21, the alignment reference of the laser drilling and the graphic exposure is guaranteed to be completely consistent, and the alignment effect can be stably achieved within 2 mi l. At the same time, 4 targets are reduced on the plate, which not only saves space but also reduces processing time and improves production efficiency.

[0043] Reference Figure 5 As shown, the diameter of the first blind hole 11 is greater than the diameter of the third blind hole 22. This can ensure that the alignment target has a higher contrast under the camera of the laser drilling machine, thereby increasing its recognition and positioning accuracy.

[0044] Reference Figure 2 As shown, the diameter of the first blind hole 11 is d1, and the diameter of the third blind hole 22 is d2, and d1 and d2 respectively satisfy the relationship: 0.6mm≤d1≤1.1mm, 0.2mm≤d2≤1.0mm. That is, the diameter of the first blind hole 11 is not greater than 1.1mm and not less than 0.6mm, and the diameter of the third blind hole 22 is not greater than 0.2mm and not less than 1.0mm. Within this range, it can be ensured that the diameter of the first blind hole 11 is greater than the third blind hole 22, which can make the laser drilling alignment target easier to identify and locate, with a smaller positioning error and improved positioning accuracy.

[0045] Reference Figure 1As shown, the inner diameter of the second blind hole 21 is d3 and the outer diameter is d4, and d3 and d4 respectively satisfy the relationship: 1.1mm≤d3≤2.4mm, 2.4mm≤d4≤4mm. That is, the inner diameter of the second blind hole 21 is not greater than 1.1mm and not less than 2.4mm, and the outer diameter of the second blind hole 21 is not greater than 4mm and not less than 2.4mm. The second blind hole 21 within this range meets the specifications of existing target production, has stronger versatility, and the alignment target is easier to identify and locate, the positioning error is small, and the positioning accuracy is improved.

[0046] Reference Figure 5 As shown, the circuit board composite target 100 further includes: a third circuit layer 30 , which is disposed above the second circuit layer 20 , and a fourth blind hole 31 is disposed on the third circuit layer 30 , and the fourth blind hole 31 covers the second blind hole 21 and the third blind hole 22 .

[0047] Specifically, the third circuit layer 30 is the topmost circuit layer, and a laser drilling alignment target and a pattern exposure alignment target are arranged below the third circuit layer 30. Therefore, a fourth blind hole 31 is arranged on the third circuit layer 30, that is, part of the copper foil on the third circuit layer 30 is ablated by laser drilling, and the exposed substrate is ablated downwards continuously. Since the laser drilling can only ablate part of the copper foil on the third circuit layer 30, it will stop when it continues downwards to encounter the copper foil on the second circuit layer 20 and the first circuit layer 10, and copper-free areas, such as the third blind hole 22 and the second blind hole 21, are etched in advance on the second circuit layer 20 and the first circuit layer 10. The third blind hole 22 and the second blind hole 21 areas can continue to be ablated, and finally all the bottom base copper that cannot be penetrated by the laser is exposed, so as to provide automatic alignment for on-site equipment and inspection of the target burning accuracy by personnel.

[0048] The area of ​​the fourth blind hole 31 is larger than the areas of the second blind hole 21 and the third blind hole 22 .

[0049] Reference Figure 4 As shown, the fourth blind hole 31 is rectangular or circular. In the embodiment of the utility model, the fourth blind hole 31 is rectangular, and in other embodiments, it can also be circular.

[0050] Reference Figure 3 and Figure 5 As shown, the circuit board composite target 100 further includes: a fourth circuit layer 40, which is arranged below the first circuit layer 10, and is an unetched circuit board. That is, the fourth circuit layer 40 is the bottommost circuit layer, and as a receiving plate for all the final burning targets, it can prevent the laser drill from burning through the bottom and causing the target point to fail.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0052] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0053] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A composite target for a circuit board, characterized in that: include: A first circuit layer, wherein a first blind hole is provided on the first circuit layer, and the first blind hole is a round hole; a second circuit layer, the second circuit layer is arranged above the first circuit layer, a second blind hole and a third blind hole are arranged on the second circuit layer, the third blind hole is arranged in the middle of the second blind hole, the second blind hole is a circular hole, and the third blind hole corresponds to the first blind hole in the up and down direction; The center of the first blind hole, the center of the third blind hole and the center of the second blind hole overlap.

2. The circuit board composite target according to claim 1, characterized in that: A diameter of the first blind hole is greater than a diameter of the third blind hole.

3. The circuit board composite target according to claim 1, characterized in that: The diameter of the first blind hole is d1, the diameter of the third blind hole is d2, and d1 and d2 respectively satisfy the relationship: 0.6mm≤d1≤1.1mm, 0.2mm≤d2≤1.0mm.

4. The circuit board composite target according to claim 1, characterized in that: The inner diameter of the second blind hole is d3 and the outer diameter is d4, and d3 and d4 respectively satisfy the relationship: 1.1mm≤d3≤2.4mm, 2.4mm≤d4≤4mm.

5. The circuit board composite target according to claim 1, characterized in that: Also includes: A third circuit layer is arranged above the second circuit layer. A fourth blind hole is arranged on the third circuit layer. The fourth blind hole covers the second blind hole and the third blind hole.

6. The circuit board composite target according to claim 5, characterized in that: The fourth blind hole is rectangular or circular.

7. The circuit board composite target according to claim 1, characterized in that: Also includes: The fourth circuit layer is arranged below the first circuit layer, and the fourth circuit layer is an unetched circuit board.

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