A method for laser alignment verification

Abstract

The application discloses a laser alignment degree inspection method, comprising the following steps: dividing a detection area in advance on a position of a PCB board edge which is not shipped before molding; manufacturing an inner layer pattern of the PCB board, digging copper on a copper foil of an alignment inner layer in the corresponding detection area to form a reverse pad, digging copper on a copper foil of a laser layer in the corresponding detection area to form a laser area, and then drilling a laser hole in the laser area, wherein the area of the laser hole is larger than the area of the reverse pad; laminating the manufactured inner layer pattern to obtain a molded PCB board; performing laser on the laser area on the molded PCB board to hit the reverse pad position; and checking the relative offset degree and direction of the laser hole and the reverse pad according to the appearance to obtain the offset of the laser hole alignment inner layer pattern. The laser alignment degree inspection method can control the offset of the laser hole alignment inner layer pattern and prevent alignment offset from exceeding the specification.

Description

Technical Field

[0001] This invention relates to a laser alignment inspection method, belonging to the field of laser inspection technology. Background Technology

[0002] Currently, in the laser hole processing process, a first piece is inspected using a magnifying glass to check for misalignment in specific areas, and then the bottom of the laser hole is scanned using AOI to check for any defects. This method can intercept defective products. Figure 1 The images show the appearance of alignment errors (NG) and alignment successes (OK). However, this method has the following drawbacks: the verification method is relatively slow, and its limitation lies in the inability to determine the degree of offset of the laser aperture from the inner layer. Figure 1 Although the alignment was detected as OK, in practice... Figure 2 The laser holes may have misalignment, posing a processing risk. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a laser alignment inspection method that can control the offset of the laser hole alignment with the inner layer pattern and prevent the alignment offset from exceeding the specification.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A laser alignment inspection method includes the following steps:

[0006] Before molding, a detection area is pre-defined at the edge of the PCB board where it will not be shipped.

[0007] To create the inner layer pattern of the PCB board, copper is removed from the copper foil of the inner layer in the corresponding detection area to form anti-solder pads, and copper is removed from the copper foil of the laser layer in the corresponding detection area to form a laser area. Then, laser holes are drilled in the laser area, wherein the area of ​​the laser hole is larger than the area of ​​the anti-solder pad.

[0008] The prepared inner layer patterns are laminated to obtain the final PCB board;

[0009] The laser is aligned with the laser area on the formed PCB board and laser-etched towards the anti-solder pad position. The relative offset and direction of the laser hole and the anti-solder pad are checked by visual inspection to obtain the offset of the laser hole to the inner layer pattern.

[0010] The anti-solder pad is circular in shape.

[0011] The laser aperture is an inverted frustum shape.

[0012] The laser-etched area is circular.

[0013] When the copper foil thickness of the laser layer is less than or equal to the Hoz copper thickness, the diameter of the laser hole is 7.9 mil, and the diameter of the anti-pad is 4.9 mil.

[0014] When the copper foil thickness of the laser layer is greater than the Hoz copper thickness, the diameter of the laser hole is 8.9 mil, and the diameter of the anti-soldering pad is 5.9 mil.

[0015] The beneficial effects of the present invention are as follows: The present invention provides a laser alignment inspection method, which first removes copper from the copper foil of the inner layer of the laser hole alignment to form a reverse pad, and then drills the laser hole. By comparing the position of the reverse pad in the laser hole, the degree and direction of the offset between the laser hole and the reverse pad are checked, so as to control the offset of the laser hole alignment inner layer pattern and prevent the alignment offset from exceeding the specification. Attached Figure Description

[0016] Figure 1 These are the alignment NG and alignment OK appearance diagrams in the existing technology;

[0017] Figure 2 for Figure 1 Alignment profile corresponding to the OK visual alignment diagram;

[0018] Figure 3 This is a schematic diagram illustrating the working principle of a laser alignment inspection method according to the present invention.

[0019] Figure 4 This is the inner layer graphic design diagram for alignment in this invention;

[0020] Figure 5 This is a diagram showing the detection results of a laser alignment inspection method according to the present invention. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0022] like Figure 3 As shown, this invention discloses a laser alignment inspection method, comprising the following steps:

[0023] Step 1: Pre-define the inspection area at the edge of the PCB board where it will not be shipped before molding.

[0024] Step two involves creating the inner layer pattern of the PCB board. Copper is removed from the copper foil of the inner layer, aligned with the laser aperture within the inspection area, to form anti-pads. These anti-pads are circular in shape. (Specific details are as follows...) Figure 4 As shown, the outer ring A is copper foil, and the inner ring B is anti-solder pads.

[0025] Step 3: Copper is removed from the copper foil of the laser layer within the inspection area to form a circular laser zone. Then, laser holes are drilled within this zone, with the laser beam passing through the copper foil to create a hole between the two layers. The final shape of the laser hole is an inverted frustum. The initial area of ​​the laser hole is larger than the area of ​​the anti-pad.

[0026] In this invention, when the copper foil thickness of the laser layer is less than or equal to the Hoz copper thickness, the diameter of the laser aperture is 7.9 mil, and the diameter of the anti-pad is 4.9 mil. When the copper foil thickness of the laser layer is greater than the Hoz copper thickness, the diameter of the laser aperture is 8.9 mil, and the diameter of the anti-pad is 5.9 mil. Through these dimensional settings, experiments have shown that the misalignment of the laser aperture with the inner layer pattern can be visually observed.

[0027] Step four: Laminate the prepared inner layer pattern to obtain the shaped PCB board.

[0028] Step 5: Align the laser area on the formed PCB board and perform laser drilling towards the anti-solder pad position. Visually inspect the degree and direction of the offset between the laser hole and the anti-solder pad to obtain the offset amount and direction of the laser hole alignment with the inner layer pattern. For example... Figure 5 As shown, the left image is a physical image of an object with "OK" alignment. The right image is a physical image of an object with "NG" alignment. This shows the degree and direction of the offset of the inner layer pattern of the laser hole alignment, allowing for timely adjustment when it exceeds the specifications.

[0029] The present invention provides a laser alignment inspection method, which first removes copper from the copper foil of the inner layer of the laser hole alignment to form a reverse pad, and then drills the laser hole. By comparing the position of the reverse pad in the laser hole, the degree and direction of the offset between the laser hole and the reverse pad are checked, so as to control the offset of the laser hole alignment inner layer pattern and prevent the alignment offset from exceeding the specification.

[0030] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for inspecting laser alignment, characterized in that: Includes the following steps: Before molding, a detection area is pre-defined at the edge of the PCB board where it will not be shipped. To create the inner layer pattern of the PCB board, copper is removed from the copper foil of the inner layer in the corresponding detection area to form a reverse solder pad. The reverse solder pad is circular. Copper is also removed from the copper foil of the laser layer in the corresponding detection area to form a laser area. The laser area is circular. Then, laser holes are drilled in the laser area. The area of ​​the laser hole is larger than the area of ​​the reverse solder pad. The prepared inner layer patterns are laminated to obtain the final PCB board; Laser-etch the laser area on the formed PCB board, aiming at the anti-solder pad position. Based on the visual inspection of the relative offset degree and direction between the laser hole and the anti-solder pad, the offset of the laser hole to the inner layer pattern is obtained.

2. The laser alignment inspection method according to claim 1, characterized in that: The laser aperture is an inverted frustum shape.

3. The laser alignment inspection method according to claim 2, characterized in that: When the copper foil thickness of the laser layer is less than or equal to the Hoz copper thickness, the diameter of the laser hole is 7.9 mil, and the diameter of the anti-pad is 4.9 mil.

4. The laser alignment inspection method according to claim 2, characterized in that: When the copper foil thickness of the laser layer is greater than the Hoz copper thickness, the diameter of the laser hole is 8.9 mil, and the diameter of the anti-soldering pad is 5.9 mil.

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