shims are created those that are produced from the metal master shim are known as u201c grandmothers u201d u201c grandmother shim u201d contains positive images of the origination at this times various copies of the original image can be duplicated see fig9 in rows on one shim and are used to print multiple copies with a single impression re combination successive generations of shims are known by various names like u201c mothers u201d u201c daughters u201d and u201c stamper shims u201d these generations of shims alternate between negative and positive images of the origination the stamper shims or production shims are used when actual production runs to print the final elements and these shims are negative images in contrary to example 1 layer 21 comprising the surface relief microstructure is generated on top of a metal substrate as illustrated in fig3 the parameters for the generation and etching of layer 21 are the same as in example 1 in contrary to example 1 the etching process of layer 22 does not stop automatically because the substrate 22 is much thicker than layer 22 in example 1 depending on the substrate used several etching means can be used either wet etching using adequate solutions or dry etching using adequate gases for instance silicon is cleaned and etched using standard methods optionally a hf based solution can be used to remove oxide either native oxide layer or a oxide coated layer followed by a strong rinse in di water in a next step anisotropic or isotropic etching is performed to achieve the required microstructure depth for example by using koh as an etching solution the depth of the microstructure in layer 22 can for example be controlled and adjusted by the etching time in combination with the temperature of the.