Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

COMBINATION CONTROL METHOD FOR PULSING LOAD APPLICATION

IP.com Disclosure Number: IPCOM000241898D
Publication Date: 2015-Jun-05

Publishing Venue

The IP.com Prior Art Database

Abstract

Modern semiconductor processing applications frequently require a pulsed RF waveform to be applied to a plasma processing chamber for etching or deposition. A typical implementation of a pulsed RF generator consistors of a DC power supply feeding an RF amplifier. When the amplifier turns on, a large current is suddenly demanded from the power supply, causing pulse droop. When the amplifier turns off, the cessation of current draw can cause a large voltage overshoot on the power supply output. To prevent pulse droop or overshoot, a very large capacitor bank is usually connected between the power supply and RF amplifier. A negative side effect of the large capacitor bank is very slow response to output voltage setpoint changes, which is required for envelope tracking applications (also known as agile rail). The slow response is partially necessitated by the DC-DC converter (also known as a Power Supply Unit or PSU) control loop bandwidth. The PSU controller is typically a feedback system using a combination of voltage and/or current mode control to regulate the power going into the pulsing load. The delay from the load pulse event to the change in the feedback variable is a major contributor to the ultimate bandwidth. The proposed invention uses a fast detection of the pulse event to “pre-position” the PSU controller. This effectively reduces the pulse droop or overshoot.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 57% of the total text.

Page 01 of 11

Combination Control Method for Pulsing Load Application

Overview

Modern semiconductor processing applications frequently require a pulsed RF waveform to be applied to a plasma processing chamber for etching or deposition. A typical implementation of a pulsed RF generator consistors of a DC power supply feeding an RF amplifier. When the amplifier turns on, a large current is suddenly demanded from the power supply, causing pulse droop. When the amplifier turns off, the cessation of current draw can cause a large voltage overshoot on the power supply output. To prevent pulse droop or overshoot, a very large capacitor bank is usually connected between the power supply and RF amplifier. A negative side effect of the large capacitor bank is very slow response to output voltage setpoint changes, which is required for envelope tracking applications (also known as agile rail). The slow response is partially necessitated by the DC-DC converter (also known as a Power Supply Unit or PSU) control loop bandwidth. The PSU controller is typically a feedback system using a combination of voltage and/or current mode control to regulate the power going into the pulsing load. The delay from the load pulse event to the change in the feedback variable is a major contributor to the ultimate bandwidth.

The proposed invention uses a fast detection of the pulse event to "pre-position" the PSU controller. This effectively reduces the pulse droop or overshoot.

L

Figure 1: Pulsed RF System example of the present invention

1

   Isolated DC-DC Converter

C

Pulsing Load

Gate driving

Pulsing controller

Pulse Detection

Controller selection

PWM controller


Page 02 of 11

Embodiments

• Isolated DC-DC converter can be any kind

• Pulse detection can be commanded pulse or sensed pulse by measuring current (for instance: output filtering capacitor curren...