Reduction of etch microloading for through silicon vias

A method of making a support structure, the method comprising:

• depositing a photoresist layer on a substrate of the support structure;
• patterning the photoresist layer;
• etching the patterned photoresist layer, wherein etching the patterned photoresist comprises:
• forming a first group of through silicon vias (TSVs) configured to electrically connect a first surface of the substrate to a first electrical interface adjacent an opposite second surface of the substrate;
• forming a second group of TSVs configured to conduct thermal energy from the first surface of the substrate to a thermal interface adjacent the second surface of the substrate;
• and
• forming a third group of TSVs configured to electrically connect the first surface of the substrate to a second electrical interface adjacent an opposite second surface of the substrate,
• wherein the first electrical interface is separate from the thermal interface and the second electrical interface, and
• the TSVs of the first group of TSVs, the TSVs of the second group of TSVs, and the TSVs of the third group of TSVs have a same depth and diameter.

A method of preparing for a support structure of a light-emitting device (LED) chip, comprising:

• preparing a photomask for patterning through silicon vias (TSVs), wherein the TSVs are divided into at least a first group and a second group, and wherein the first group of TSVs provides electrical connection for the LED chip and the second group of TSVs provides a function of heat dissipation for the LED chip;
• wherein the first group of TSVs are arranged in a first pattern with a first pattern density and the second group of TSVs are arranged in a second pattern with a second pattern density, and wherein a difference between the first pattern density and the second pattern density has an absolute value between about 0.1% to about 5%;
• depositing a photoresist layer on a substrate for the support structure;
• patterning the deposited photoresist layer on the substrate by using the prepared photomask;
• and
• etching the substrate by using a deep reactive ion etching process for silicon after the deposited photoresist layer is patterned.