How do I create a halftone pattern in Photoshop?

In Photoshop, you can create a halftone pattern by first creating a gradient. Then, you can use the 'Bitmap' setting when rasterizing the gradient. Adjust the 'Dots' and 'Dithering' settings to control the density and variation of the dots. Save this as a pattern and apply it as a fill layer to your background. You can also find pre-made halftone patterns online.