semi合集-English.pdf - 第1006页

SEMI E136-1104 © SEMI 2004 4 Figure 2 Calorimeter Calibration Connection Diagram 9.3.1 Use a calorimeter equipped with a coolant system. NOTE 5: Most calorim eter systems use either a tap-wa ter coolant system or a rec i…

SEMI E136-1104 © SEMI 2004 3

adequate lifting devices for large weights such as long

RF cables and generators themselves.

7.4 Persons performing tests should determine which

method of water cooling of the resistor in the RF

termination is utilized by the test device manufacturer

and should take steps to ensure safe use of the device.

7.4.1 Cooling-water flow rates should be appropriate to

the test device manufacturer’s recommendations for

cooling of the power load level being tested. Consult

the RF generator operating manual load specifications

for this information.

7.4.2 An RF termination using internal resistor cooling

only is highly recommended because such resistors (of

the tubular ceramic, thin film type) are usually cooled

by routing the coolant to the inside of the ceramic tube

and away from the resistive film, thereby eliminating

the possibility of electrolysis affecting the resistive

film.

7.4.3 In an alternative method, the coolant is routed on

both the inside and the outside of the resistor. While

this method provides for more efficient cooling, the

proximity of the coolant to the resistive film can

potentially result in damage to the resistive film caused

by electrolysis generated by the DC energy passing

through the fluid in the termination.

7.4.3.1 For this reason, if an RF termination using both

internal and external cooling is used, it is important to

periodically check the resistor for damage due to

electrolysis. This can be done easily by measuring the

resistance of the load resistor using a simple digital

multimeter.

7.4.3.2 With the RF termination disconnected from the

RF cable, place one probe on the center conductor of

the termination, and the other probe on the

termination’s outer conductor.

7.4.3.3 Measure the DC resistance of this path. If the

DC resistance is more than 53 , replace the resistor in

the termination.

7.5 In order to prevent the possibility of ground loops

between the RF generator and the calorimeter system,

be sure to operate the calorimeter and the RF generator

on the same AC supply.

8 Test Setup for RF Generator Power Output

Test

8.1 The test setup for the RF generator output power

test consists of the RF generator connected to the

calorimeter power meter through a length of coaxial

cable.

8.2 Prior to making any measurements, calibrate the

calorimeter power meter using a source of stable DC

energy.

9 Test Procedure for Determining RF

Generator Output Power

9.1 Calorimetric power meters provide excellent

reference standards for the measurement of RF energy

in that they are capable of measuring the true heating

power of a waveform, including any harmonic- or

nonharmonic-related frequency components. The

technique employed for this test is to first calibrate the

calorimetric power meter with DC energy, which can

be very precisely determined. Then, use two digital

multimeters (e.g., Fluke™ 87 or equivalent) to

determine the actual DC power applied to the

calorimeter. Finally, once the DC calibration has been

performed at a particular power level, connect the

output of the RF generator under test to the calorimeter

and measure the output power of the RF generator. The

basic steps involved in the use of this system are

outlined below.

9.2 Calibrate the Calorimeter — Calibrate the

calorimeter with the stable DC power supply, using the

two digital multimeters to read the voltage and current

applied to the calorimeter’s RF load.

9.3 Connections — Connect the DC power supply, the

digital multimeters, and the RF load according to

Figures 1 and 2. Make the connections between the

multimeters, the DC power supply, and the RF load

using high-quality low-loss cable and high-quality

corrosion-free cable terminations.

Figure 1

Calorimeter Calibration Configuration

SEMI E136-1104 © SEMI 2004 4

Figure 2

Calorimeter Calibration Connection Diagram

9.3.1 Use a calorimeter equipped with a coolant

system.

NOTE 5: Most calorimeter systems use either a tap-water

coolant system or a recirculating system of some type. Best

results may be obtained through the use of a self-contained

heat exchanger and coolant recirculating system.

9.3.2 Make all of the electrical and coolant connections

to the calorimeter.

9.3.3 Apply main power to the calorimeter system and

allow one hour for stabilization.

9.3.4 Load Differential Temperature — Most

calorimeter systems will yield optimum performance

when certain operating parameters relating to the

differential temperature across the RF load and the flow

rate are maintained. In most cases, a differential

temperature of 2°C represents a good beginning point.

The coolant flow rate may then be set to provide for

this differential temperature.

9.3.4.1 The following formula may be used to arrive at

the correct coolant flow rate.

Power = 69.32 ×



T × Flow Rate (1)

where:

Power is in W,



T is in C, and

Flow Rate is in L/min.

9.3.4.2 Solving for flow rate yields:

Flow Rate = (Power / 69.32) /



T (2)

9.3.5 Coolant Types — In most cases, the coolant used

in calorimetric power measurement systems is pure

distilled water. In this case, most modern calorimeters

will automatically correct for changes to the coolant

physical characteristics (e.g., specific heat, specific

gravity) as the coolant temperature changes.

9.3.5.1 If coolant other than pure water is used and the

calorimeter chosen will not automatically compensate

for changes to the coolant, adjust the power readings

obtained for the effects of the coolant changes. Consult

the calorimeter operating manual for specific details.

9.3.6 Calorimeter Calibration — Following the

calorimeter warm-up, the device is ready for

calibration.

9.3.6.1 With the calorimeter operating at the

appropriate flow rate, apply DC power to the RF load,

according to the voltage and current readings obtained

with the two digital multimeters.

9.3.6.2 Multiply the voltage reading by the current

reading to obtain the power applied to the load.

9.3.6.3 Allow 15 minutes for the calorimeter reading to

stabilize.

9.3.6.4 Using the procedure in the calorimeter

operating manual, set the calorimeter such that the

calorimeter reading is exactly the same as that obtained

using the voltage and current meters.

9.3.6.5 At this point, add any offsets that are associated

with interconnecting cable losses, as outlined in

Sections 6.5.2 and 6.5.3.

9.3.6.6 The calorimeter is now calibrated at this

specific power level.

NOTE 6: If a new power level is selected, repeat this process

in order to compensate for instrumentation linearity effects of

the calorimeter.

9.3.7 RF Generator Testing — With the calorimeter

calibrated at a particular power level, it is now possible

to test the RF generator power output at this level.

9.3.8 Connections — Connect the RF generator output

to the RF load according to Figure 3. Use cables and

connectors between the RF generator output and the RF

load of a high-quality, low-loss type. As outlined

above, some power will be lost in the cables between

the generator and the load. Add these losses as offsets

to the calorimeter reading, in order to obtain the total

power output of the generator. Base the losses upon

cable length, cable type, and operating frequency. See

SEMI E114 test method for details on cable loss

compensation.

Figure 3

RF Generator Output Power Test

9.3.9 Testing — With the connections made according

to Figure 2, apply main power to the RF generator and

allow 15 minutes for stabilization. The power reading

obtained on the calorimeter will represent the total

power output of the RF generator, including harmonics.

9.3.9.1 Begin RF generator testing at a power level that

represents 10% of the maximum output power of the

RF generator.

9.3.9.2 Repeat the test at RF generator power levels of

40% of maximum, 70% of maximum, and maximum

power.

9.3.9.3 Also, conduct tests corresponding to each range

on the RF generator power output meter.

NOTE 7: Calibrate the calorimeter power meter to the DC

standard at each power level used.

NOTICE: SEMI makes no warranties or

representations as to the suitability of the standards set

forth herein for any particular application. The

determination of the suitability of the standard is solely

the responsibility of the user. Users are cautioned to

refer to manufacturer's instructions, product labels,

product data sheets, and other relevant literature,

respecting any materials or equipment mentioned

herein. These standards are subject to change without

notice.

By publication of this standard, Semiconductor

Equipment and Materials International (SEMI) takes no

position respecting the validity of any patent rights or

copyrights asserted in connection with any items

mentioned in this standard. Users of this standard are

expressly advised that determination of any such patent

rights or copyrights, and the risk of infringement of

such rights are entirely their own responsibility.

International), 3081 Zanker Road, San Jose, CA 95134. Reproduction of

the contents in whole or in part is forbidden without express written

consent of SEMI.