Energy grid test method for an ldi direct write exposure machine

Abstract

The application discloses an energy grid test method of an LDI direct writing exposure machine, which comprises the following steps: S1, obtaining a substrate sample and performing pretreatment; S2, coating ink on the pretreated substrate, baking and curing, and then placing the substrate at a preset position of an exposure machine chuck pad; S3, obtaining an energy test pattern based on a preset proportion of a graphic pixel, and performing exposure treatment on the energy test pattern by using the exposure machine; and S4, developing and reading the energy test pattern obtained after the exposure treatment, and obtaining the energy grid of the energy test pattern. The energy test pattern is directly scanned and imaged onto photosensitive ink by a laser beam through a spatial light modulator, and the energy grid of the pattern is read after development, so that the problem that the service life of an exposure ruler in the prior art is limited and the exposure ruler needs to be replaced regularly and has high cost is solved. Meanwhile, the depreciation of the exposure ruler reduces accuracy, and the infrared function easily causes high heat of the exposure ruler, thereby causing risks such as fire.

Description

Technical Field

[0001] This invention relates to the field of printed circuit board technology, and in particular to a method for testing the energy grid of an LDI direct-write exposure machine. Background Technology

[0002] LDI (laser direct imaging) exposure machines are mainly used in the exposure process of PCB (Printed Circuit Board) production. Currently, there are two main types of exposure equipment in the PCB industry: projection exposure equipment and laser direct imaging (LDI) equipment. Projection exposure equipment transfers the image from the film onto a photosensitive dry film or ink through projection; LDI equipment directly scans and images the exposed image onto the photosensitive dry film using a spatial light modulator. In production, PCB manufacturers typically use an exposure scale for exposure to accurately control the exposure energy of liquid photosensitive oil and liquid solder resist ink, and then read the energy grid of the pattern after development.

[0003] The shortcomings of existing technology are that the current exposure ruler has a limited lifespan and needs to be replaced regularly, resulting in high costs; moreover, as the exposure ruler's usage cycle increases, its depreciation will directly affect the accuracy of the exposure ruler; when used on an exposure machine with infrared heating function, the exposure ruler is easily damaged or may cause fire risks. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology. To achieve the above objective, an energy grid testing method for an LDI direct-write exposure machine is adopted to solve the problems mentioned in the background technology.

[0005] A method for testing the energy grid of an LDI direct-write exposure machine, comprising the following steps:

[0006] Step S1: Obtain a substrate sample and perform pretreatment, which includes cleaning, roughening, and drying.

[0007] Step S2: Apply ink to the pretreated substrate and bake to cure it. Then place the substrate at the preset position of the exposure machine suction cup pad.

[0008] Step S3: Obtain the energy test pattern based on the preset ratio of graphic pixels, and expose it using an exposure machine;

[0009] Step S4: Develop and read the energy test pattern obtained after exposure processing to obtain the energy grid of the energy test pattern.

[0010] As a further aspect of the present invention: the energy test pattern is composed of 21 levels of pixels with different densities, wherein the size of each level of pixel, the spacing between pixels, and the ratio of pixel area to total area are set according to a preset ratio.

[0011] As a further aspect of the present invention: the area ratio between the first and twenty-first pixels of the energy test pattern gradually decreases.

[0012] As a further aspect of the present invention: the proportional relationship of the energy test pattern is based on the energy transmittance design of the exposure ruler.

[0013] Compared with the prior art, the present invention has the following technical advantages:

[0014] Using the above technical solution, the energy test pattern is directly scanned onto photosensitive ink via a spatial light modulator using a laser beam. After development, the energy grid of the pattern is read. Simultaneously, by setting the pixel density of the energy test pattern according to a specific ratio, the testing process is simplified, eliminating the need for an exposure ruler and saving time. It also avoids the problem of exposure ruler depreciation directly affecting its accuracy as the exposure ruler's lifespan increases. Attached Figure Description

[0015] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings:

[0016] Figure 1 This is a schematic diagram illustrating the steps of the energy grid testing method according to an embodiment of this application;

[0017] Figure 2 This is a flowchart of an energy grid testing method according to an embodiment of this application;

[0018] Figure 3 This is a schematic diagram of an energy test according to an embodiment of this application. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please refer to Figure 1 and Figure 2 In this embodiment of the invention, an energy grid testing method for an LDI direct-write exposure machine includes the following steps:

[0021] Step S1: Obtain a substrate sample and perform pretreatment, which includes cleaning, roughening, and drying.

[0022] Step S2: Apply ink to the pretreated substrate and bake to cure it. Then place the substrate at the preset position of the exposure machine suction cup pad.

[0023] Step S3: Obtain the energy test pattern based on the preset ratio of graphic pixels, and expose it using an exposure machine;

[0024] Step S4: Develop and read the energy test pattern obtained after exposure processing to obtain the energy grid of the energy test pattern.

[0025] In the specific implementation steps, the energy test pattern is composed of pixels of 21 different densities. The size of each pixel, the spacing between pixels, and the ratio of pixel area to total area are set according to a preset ratio. As shown in Table 1 below, the pixel size, spacing, and area ratio are represented.

[0026] Table 1 Distribution ratio of pixels at each level

[0027]

[0028] In the specific implementation steps, as shown in Table 1 above, the area ratio between the first and twenty-first pixels of the energy test pattern gradually decreases.

[0029] like Figure 3 As shown in the figure, the diagram is a schematic diagram of the energy test. The area ratio between the pads in the first to the twenty-first grid gradually decreases. The first grid accounts for 100%, the second grid 71%, the third grid, and so on, decreasing in proportion to the ratio in the table above.

[0030] As shown in Table 2 below, the table is a table of energy transmittance of the exposure ruler. The proportional relationship of the energy test graphic is based on the energy transmittance of the exposure ruler.

[0031] Table 2 Energy transmittance of exposure rulers

[0032]

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention. The scope of the invention is defined by the appended claims and their equivalents, all of which should be included within the scope of protection of the invention.

Claims

1. A method for testing an energy grid of an LDI direct write exposure machine, characterized in that The specific steps include: Step S1, obtaining a substrate sample and performing pretreatment, the pretreatment including cleaning, roughening, and drying treatment; Step S2, coating ink on the pretreated substrate and baking and curing, and then placing the substrate at a preset position of an exposure machine chuck pad; Step S3, obtaining an energy test pattern based on a preset proportion of graphic pixels, and exposing the energy test pattern by using the exposure machine; Step S4, developing and reading the energy test pattern obtained after the exposure, to obtain an energy grid of the energy test pattern; The energy test pattern is composed of 21 different density pixel points, wherein the size of each order pixel point, the pixel point spacing, and the ratio of the pixel point area to the total area are set according to the preset proportion; The proportion relationship of the energy test pattern is designed based on the energy transmittance of the exposure ruler; The area proportion between the first grid and the twenty-first grid of the pixel points of the energy test pattern gradually decreases.

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