Hight Density PCB Stepper EM-5434

The stepper is intended to perform a lithography process in the production of the fifth generation high density PCBs: MCM, Flip Chip, (BGA/CSP). Its operation is based on the projection (contact-free) transfer of a pattern from a reticle onto a panel coated with a photoresist, and step-and-repeat exposure of the pattern over the panel.

• Large field of a projection lens.
• Possibility to stitch a very large integral pattern on a substrate.
• On-line change of a scale of the projection system in a wide range.
• Small distortion of a lens in the whole range of the scale change.
• High resolution and a big depth of focus.
• Small losses of light in a lens and high energy density of exposure light on a panel
• Global or shot by shot precision TTL alignment with bright field or dark field illumination with non-exposure light.
• Controlled position of a panel stage by means of laser interferometers.
• Automatic focusing for each shot.
• Option of manual or automatic loading of reticles.
• Automatic loading of panels

The listed features of the stepper allow to provide high throughput with high accuracy of imaging and alignment of an image with previous layers of a PCB. The projection method of imaging in a clean zone ensures low rejection and a high product yield.

High energy density of exposure light on a panel allows effectively to expose not only liquid, dry thin-film photoresists, but also solder masks.

If required to transfer an image having the size bigger than the size of a projection lens field, it is possible to use an option of stitching. In this case one integral pattern is transferred from a 9” reticle (max. size 200 x 200mm) in sequence in two exposures with a partial light overlapping of a borderline between two frames (stitching zone).

An on-line change of a scale of the projection system in a wide range allows to compensate for a change of sizes of a substrate occurring during the processes of a PCB manufacture.

High image contrast at small projection lens aperture allows to achire practically vertical side walls in thick resist.

Specifications

Projection lens resolution L/S 10 µm Projection lens field 100 x 200; 120 x 150 mm Overlay accuracy 4.8 µm Maximum field with stitching 200 x 200 mm Projection lens scale 1:1 Automatic correction of scale ±1000 ppm Lens distortion ±2.5 µm Depth of focus ±100 µm Working wavelengths i-(365nm), h-(405nm); g-(436nm) Exposure light energy density in the substrate plane 125 mW/cm2 Uniformity of irradiation in the image plane ±5 % Maximum substrate size 510 x 610 mm Reticle size 230 x 230 mm Dimensions (without environment chamber and loader) 2550 x 1240 x 1930 mm Weight 3800 kg