TWI625604B - Transmissive laser direct imaging system - Google Patents

Abstract

The present invention relates to a penetrating laser direct imaging system, which mainly includes a stage and a laser exposure device that can be relatively displaced in a Y direction, and during the displacement process, the laser exposure device can be Scan the substrate on the stage in the X direction to form a latent image pattern on the substrate. In detail, the laser exposure device has a laser module, which includes a linear laser light source and a penetrating scanner. The length direction of the linear laser light source is inclined to the X direction. The transmissive scanner has a plurality of chirps, and its rotation axis is parallel to the length direction of the linear laser light source. In addition, during the rotation, the multiple facets allow each laser beam to penetrate and form an oblique stripe of exposure spots on the substrate, and the exposure spots formed by two adjacent laser beams are at There is some overlap in the projections in the X direction.

Description

Penetrating laser direct imaging system

The invention relates to a Laser Direct Imaging System (LDI), in particular to a laser direct imaging system that uses linear scanning imaging.

In recent years, the requirements for precision in the manufacturing process of printed circuit boards (PCBs) have been increasing, making the traditional contact printing process gradually unable to meet the requirements. In response, many printed circuit board manufacturers have switched to the direct imaging system (LDI system) to solve the problem of yield and yield. Compared with the traditional lithography technology, this laser direct imaging system can directly write the corresponding circuit on the substrate after the circuit pattern data of the circuit board is sent to the computer without using a photomask. Patterns are used to manufacture circuit boards, which not only greatly improves precision, but also effectively reduces production costs.

Taiwan Patent No. 523968 discloses a direct laser imaging system that can form a latent image directly on a substrate surface without the use of a mask. The direct laser imaging system mainly includes a laser light source and a reflective scanner disposed between the laser light source and the substrate. The laser light source is used for outputting a laser beam carrying image information. The reflective scanner has a polygon mirror, which scans the substrate when rotating to form the latent image pattern.

It is worth noting that traditional reflective scanning methods have many disadvantages. First, as shown in Figure 11, when the reflective polygon mirror 9 is used, the change in the height of the substrate 4 will cause the position of the focus points F3 and F4 to shift, which will affect its latent image pattern. Image quality. Furthermore, as shown in FIG. 12, the focal point F of the conventional mirror surface 91 on the laser beam 92 is different due to the rotation angle of the mirror surface 91, which causes the out-of-focus situation around the image when the substrate 4 is imaged. In order to improve these shortcomings, the direct laser imaging system shown in the aforementioned Taiwan patent is to set a F-theta lens on the optical path between the reflective scanner and the substrate to correct it, thereby improving imaging. quality.

Different from the conventional reflective laser direct imaging system, the present invention provides a new penetrating laser direct imaging system. By using the penetrating scanner for direct imaging, the defocus of the reflective scanner can be avoided. Or focus shift, and the optical system is greatly simplified to significantly reduce equipment costs. In addition, the laser exposure device of the penetrating laser direct imaging system of the present invention adopts a linear scanning method of a plurality of laser diodes in a row, which can greatly increase the scanning speed.

Specifically, the penetrating laser direct imaging system of the present invention mainly includes a carrier and a laser exposure device. The stage is used for carrying a substrate, and the substrate is coated with a photosensitive layer. The laser exposure device can be relatively displaced with the stage in a Y direction, and can linearly scan the photosensitive layer of the substrate in an X direction during the relative displacement to form a latent image pattern on the photosensitive layer. .

In detail, the laser exposure device has a first laser module. The first laser module mainly includes a linear laser light source, an optical component, and a penetrating scanner. The linear laser light source includes a plurality of laser diodes arranged at intervals along its length direction to output a plurality of laser beams parallel to each other, and the length direction of the linear laser light source is inclined to the X direction. The optical component has a plurality of focusing lens units for respectively focusing the laser beams on the substrate. The transmissive scanner has a plurality of beams that can rotate, and the rotation axis of the plurality of beams is parallel to the length direction of the linear laser light source, and has multiple facets for the laser beams to enter. Each facet of the multiple beams can deflect each incident laser beam, and then output the light in parallel after being refracted by the multiple beams, and scan the oblique direction of the photosensitive layer of the substrate after rotating an angle. On the path A stripe-shaped exposure spot is formed, and the projections of the stripe-shaped exposure spot formed by two adjacent laser beams in the X direction partially overlap.

Preferably, the laser exposure device further includes a second laser module having the same structure as the first laser module, wherein a stripe formed by a last laser beam of the first laser module The exposure spot and the projection of the stripe-shaped exposure spot formed by the first laser beam of the second laser module in the X direction partially overlap.

Preferably, the first laser module of the laser exposure device further includes a water cooling system for cooling the linear laser light source of the first laser module.

Preferably, each focusing lens unit of the first laser module of the laser exposure device includes a lens barrel and a focusing lens provided in the lens barrel, and the lens barrel is sleeved on the corresponding axial axis. A laser diode on a base.

Preferably, the plurality of frames are disposed on an optical path between the focusing lenses of the optical component and the stage.

100‧‧‧ penetrating laser direct imaging system

1‧‧‧machine

11‧‧‧ carrier

12‧‧‧ Dragon Gate

2‧‧‧laser exposure device

3‧‧‧control unit

4‧‧‧ substrate

41‧‧‧Photosensitive layer

5‧‧‧The first laser module

51‧‧‧Linear laser light source

510‧‧‧laser diode

511 / 511a / 511b / 511l‧‧‧laser beam

512‧‧‧ base

513‧‧‧boat rack

52‧‧‧Optical components

520‧‧‧Focus lens unit

521‧‧‧Mirror Tube

522‧‧‧Focus lens

53‧‧‧ Penetrating Scanner

531‧‧‧ more than

532‧‧‧Motor

533‧‧‧ facet

54‧‧‧Water cooling system

6‧‧‧Second Laser Module

9‧‧‧ polygon mirror

91‧‧‧Mirror

92‧‧‧laser beam

The first figure is a schematic diagram of the three-dimensional structure of the penetrating laser direct imaging system of the present invention.

The second figure is a schematic diagram of the three-dimensional structure of the laser exposure device in the penetrating laser direct imaging system of the first figure.

The third diagram is a partially enlarged schematic diagram of the second diagram.

The fourth figure is a schematic plan view of two laser modules and a substrate of the laser exposure device of the second figure.

The fifth figure is a schematic diagram of the three-dimensional structure of a laser module of the laser exposure device in the second figure.

The sixth figure is a partial cross-sectional structure diagram of the laser module in the fifth figure.

The seventh figure is a schematic sectional view taken along the line VII-VII in the sixth figure.

The eighth diagrams A through C show the process of the laser beam forming a laser spot on the substrate when the multi-scanner scanner of the present invention rotates an angle.

The ninth figure is a schematic view showing the stripe laser spot formed by the laser exposure device on the X-Y coordinate axis.

The tenth figure shows that the laser beam of the multi-scanner scanner of the present invention can vertically enter the surface of the substrate during scanning, without causing the focus point to shift due to the change of the substrate height.

The eleventh figure shows a situation in which the focus point is shifted due to a change in the substrate height when the conventional polygon scanner is scanning a laser beam.

The twelfth figure shows the situation where the conventional mirror surface is out of focus when the laser beam is reflected due to different rotation angles.

The first to tenth drawings show a preferred embodiment of the penetrating laser direct imaging system 100 of the present invention, which is used to directly write a digital pattern information into a substrate 4 to form a photosensitive layer 41 on the surface of the substrate 4 (Eighth Figure) A latent image pattern is formed. As shown in the first figure, the penetrating laser direct imaging system 100 generally includes a machine 1, a laser exposure device 2, and a control unit 3. The laser exposure device 2 is disposed on a gantry 12 of the machine 1. The machine 1 has a carrier 11 for carrying the substrate 4.

Specifically, the stage 11 and the substrate 4 thereon can be advanced in a Y direction, and are relatively displaced from the laser exposure device 2 on the gantry 12. In addition, the laser exposure device 2 can make each position of the photosensitive layer 41 of the substrate in the X direction be selectively exposed by the laser exposure device 2 during the relative displacement with the stage 11. To form a two-dimensional latent image pattern (not shown) on the photosensitive layer 41. The latent image pattern can be embodied on the substrate 4 through a subsequent development process.

The second diagram is a schematic diagram showing the positional relationship between the laser exposure device 2 and the substrate 4 in the first diagram. The laser exposure device 2 includes a first laser module 5 and a second laser module 6 having the same structure. As shown in the plan view of the fourth figure, the first and second laser modules 5 and 6 are parallel to each other, but inclined to the advancing direction of the substrate 4 (that is, the Y direction).

For simplicity, this first laser module 5 is used as an example for illustration. The structure of the second laser module 6 is comparable to the structure of the first laser module 5. As shown in the fifth and sixth figures, the first laser module 5 includes a linear laser light source 51, an optical component 52, a penetrating scanner 53, and a water cooling system 54. The length direction (M) of the linear laser light source 51 is inclined to the X direction (as shown in the fourth figure), and includes a complex laser diode 510 (as shown in the sixth figure). The light sources 51 are arranged at intervals in the length direction (M) to output a plurality of laser beams 511 parallel to each other. Similarly, the optical component 52 has a plurality of focusing lens units 520 arranged in a row along the length direction (M) of the linear laser light source 51 to respectively focus the laser beams 511 to the substrate 4 correspondingly. Each focusing lens unit 520 includes a lens barrel 521 and a focusing lens 522 disposed in the lens barrel 521. As shown in the seventh figure, the lens barrel 521 is axially sleeved on a base 512 of the corresponding laser diode 510, and the base 512 is further fixed on a boat frame 513. In this way, it is possible to eliminate the need for complicated and precise alignment between each laser diode 510 and the corresponding focusing lens 522 on the optical axis. As shown in the fifth figure, the water cooling system 54 is connected to the boat racks 513 of the linear laser light source 51 to dissipate the laser diodes 510 of the linear laser light source 51 to prevent heat. Overheating failure.

Referring again to the sixth figure, the penetrating scanner 53 has a multi-roller 531 and a motor 532 for driving the multi-roller 531 to rotate. The axis of rotation of the multiple beams 531 is parallel to the length direction (M) of the linear laser light source 51, and the multiple beams 531 has a plurality of facets 533 for the laser beams 511 to enter. As shown in FIG. 8A, each facet 533 of the multi-roller 531 can deflect each incident laser beam 511 and emit light in parallel after being refracted by the multi-roller 531. After the angle (as shown in FIG. 8C), a stripe-shaped exposure spot S is formed on an oblique scanning path (N) of the photosensitive layer 41 of the substrate 4.

Referring to the enlarged view of the third figure, the projections in the X direction of the stripe exposure spots S ₁₁ and S ₁₂ formed by two adjacent laser beams 511 a and 511 b partially overlap. Similarly, as shown in the ninth figure, the stripe laser spots generated by two adjacent laser modules 5 and 6 also partially overlap, and the last laser beam 5111 of the first laser module 5 is partially overlapped. The projected stripe exposure spot S _1N and the projection of the stripe exposure spot S ₂₁ formed by the first laser beam 611 a of the second laser module 6 in the X direction are partially overlapped. In other words, the laser diodes 510 of the first laser module 5 can indeed be exposed to different positions of the photosensitive layer 41 of the substrate 4 in the X direction, and during the progress of the substrate 4 being scanned, The control unit 3 (first picture) can control the switches of the laser diodes 510 of the laser exposure device 2 and make each exposure spot or unexposed position form a pixel point of the latent image pattern. , And there will be no blank gap between adjacent pixel points. In addition, as shown in the tenth figure, the 稜鏡 531 of the penetrating scanner 53 of the present invention has the advantage of accurate focusing. After the laser beam is refracted by the 稜鏡 531, the height of the substrate 4 changes and The position of the focus points F ₁ and F ₂ will not be shifted.

With the above setting, the penetrating laser direct imaging system of the present invention directly images through its penetrating scanner, which can avoid problems such as out-of-focus or focus shift of the reflective scanner, and its matching The optical system has also been greatly simplified, which can significantly reduce equipment costs. In addition, the laser exposure device of the penetrating laser direct imaging system of the present invention adopts a linear scanning method of a plurality of laser diodes in a row, which can greatly increase the scanning speed.

In any case, anyone can get enough teaching from the description of the above examples, and understand that the content of the present invention is indeed different from the prior art, and has industrial applicability and is sufficiently progressive. It is true that the present invention has met the patent requirements, and the application was filed according to law.

Claims (5)

A penetrating laser direct imaging system includes: a carrier for carrying a substrate, the substrate is coated with a photosensitive layer; a laser exposure device can be relatively displaced with the carrier in a Y direction, and During the displacement process, the position of the photosensitive layer of the substrate on the stage in the X direction can also be selectively exposed by the laser exposure device to form a latent image pattern. The laser exposure device has a first A laser module. The first laser module includes: a linear laser light source including a plurality of laser diodes spaced apart along its length direction to output a plurality of laser beams parallel to each other, wherein The length direction of the linear laser light source is inclined to the X direction; an optical component having a plurality of focusing lens units for respectively correspondingly focusing the laser beams to the substrate; and a penetrating scanner having a rotatable A plurality of beams, the rotation axis of the plurality of beams is parallel to the length direction of the linear laser light source, and has multiple facets for the laser beams to enter, wherein each facet of the plurality of beams can make Every incident The light beam is deflected, and the light is parallelly emitted after being refracted by the multiple beams. After being rotated an angle, a stripe of exposure light is formed on an oblique scanning path of the photosensitive layer of the substrate, and two adjacent lasers The projections of the stripe-shaped exposure spots formed by the light beams in the X direction partially overlap. According to the penetrating laser direct imaging system described in item 1 of the patent application scope, wherein the laser exposure device further includes a second laser module having the same structure as the first laser module, wherein the first The stripe exposure spot formed by the last laser beam of a laser module and the projection of the stripe exposure spot formed by the first laser beam of the second laser module in the X direction partially overlap. The penetrating laser direct imaging system according to item 1 of the patent application scope, wherein the first laser module of the laser exposure device further includes a water cooling system for the first laser module. The linear laser light source dissipates heat. According to the penetrating laser direct imaging system described in item 1 of the patent application scope, wherein each focusing lens unit of the first laser module of the laser exposure device includes a lens barrel and a A focusing lens, and the lens barrel is sleeved axially on a base of the corresponding laser diode. The penetrating laser direct imaging system according to item 1 of the scope of the patent application, wherein the plurality of beams are disposed on an optical path between the focusing lenses of the optical component and the stage.