One of the most outstanding advantages is its cost benefit, which allows GaAs RF IC manufacturers to secure their price competitiveness. This cost benefit stems from the
difference in material cost of substrates between silicon and GaAs wafer. This benefit will be
maximized if passive ratio of GaAs RF IC becomes larger, although additional die attachment cost (between customer's active devices and Telephus’passive components) is required.
Furthermore, GaAs RF IC manufacturers will benefit from the increase in available chips per
wafer, generated by dedicated utilization of GaAs wafer for the production of active
components only.
In the GaAs MMIC marketplace seven major players, who have 67% of the worldwide market share, are undergoing serious market competition in their profit and market share as well.
Taking into consideration this market environment, Telephus’ passive foundry service can be recommended as their optimal choice to win in the market of GaAs MMIC .


<Available specifications of R,L,C values on STO silicon substrate --- as of May 2001>

* Resistor: power rating = 50mW, 100mW, 300mW

- Benefit analysis of passive foundry service on STO silicon substrate -
- Telephus’ passive foundry service provides increased benefit in your sales turnover and
profit as well.

This benefit of passive foundry service depends on chip size of GaAs RF IC in die form (bare chip) and its active ratio inside. As described in the tables below, blue-shadowed areas
refer to increased benefit that stem from the use of Telephus’ passive foundry service.
For instance, if bare chip size of GaAs RF IC is 0.5 ㎟ and its active area is 5%, then sales revenue per GaAs wafer, with Telephus’ foundry service, is increased to U$ 62,162 from
U$ 36,000 of sales turnover that is made without passive foundry service.
Profit will also be increased to U$ 57,184 from U$ 25,500 if passive foundry service is
provided.


<Turnover comparison of one 6” GaAs wafer with Telephus’ passive foundry service & w/o passive foundry service >

Bare Chip size (㎟)	Sales turnover per one GaAs Wafer	Sales turnover per GaAs wafer with Telephus' passive foundry service
		% of active area from total space of GaAs RFIC
0.5 1 1.6 2	$36,000 $18,000 $11,250 $9.000	5%	10%	20%	35%	50%
		$62,162	$49,404	$37,134	$28,243	$23,244
		$49,404	$37,134	$26,305	$19,067	$15,231
		$40,969	$29,586	$20,127	$14,138	$11,083
		$37,134	$26,305	$17,560	$12,160	$9,452

<Profit comparison of one 6” GaAs wafer with Telephus’ passive foundry service & w/o passive foundry service >

Bare Chip size (㎟)	Sales turnover per one GaAs Wafer	Profit a GaAs wafer with Telephus' passive foundry service
		% of active area from total space of GaAs RFIC
0.5 1 1.6 2	$25,000 $12,250 $5,906 $3,477	5%	10%	20%	35%	50%
		$57,184	$44,449	$32,208	$23,348	$18.689
		$44,449	$32,208	$21,419	$14,221	$10,772
		$36,032	$24,686	$16,915	$9,333	$6,620
		$32,208	$21,419	$12,725	$7,375	$5,016

As shown in the above, the benefit of Telephus’ passive foundry service becomes maximized as active ratio of RF IC in die form becomes smaller. For reference, detailed calculation formula is skipped herein. (For instance, 15,000 mm2 of GaAs wafer size and U$ 1.2 of sales price for
one GaAs RF IC (regardless of its bare chip size) were assumed.) However, according to
Telephus, there will be additional costs involved in using Telephus’ passive foundry service
(these costs were already considered when the above analysis was made).

- Additional wire bonding cost between active device of bare chip and Telephus’ STO silicon substrate that includes integrated passive components inside (for this analysis, they took U$
0.1 for wire bonding cost of 20 pins (out lead) per RF IC).

- Increased size for GaAs bare chip: for electrical connection between the active device and STO silicon substrate, GaAs bare chip requires additional space for pad (70um x 70um) and space between sawing lane and pad (min. 50um).

- Size increase of STO silicon substrate: there will be additional space of STO silicon substrate required for replacing passive area of GaAs RF IC by STO silicon substrate (space between
the edge of active device for bare chip and bonding pad on STO silicon substrate
(for conductive film: 150 um), Telephus’ inductor conventional size (300 um)).

- Final assembly packaging cost (U$ 0.15 in this analysis) and U$ 0.1 of additional test cost was added In this analysis.

In conclusion, Telephus’ passive foundry service provides breakthrough benefits, although
there will be additional costs involved. For constantly changing GaAs RF MMIC industry,
lowering manufacturing cost will be one important success factor for many GaAs RF IC
manufacturers. In this regard, Telephus' passive foundry service will help them to achieve
their goals. Increased sales turnover can be also one attractive benefits they can expect from
this foundry service.