Assembly, Testing and Packaging Plants: Where the Heat Goes
Semiconductor & Electronics · 6 min read ·
The short answer
Assembly, testing and packaging plants heat most of their core process steps electrically at the tool. The boiler house serves the surrounding utilities: cleanroom and controlled-area humidification, heated cleaning and rinsing, facility hot water, and in some configurations thermal oil for press and platen heating.
When electronics manufacturing expands into a new country, it rarely starts with wafer fabrication. It starts downstream, in assembly, testing and packaging — the stage where finished dies become packaged, tested components. These plants are less capital-intensive than a fab, employ more people, and are the realistic near-term prospect for Philippine industrial estates.
They also have a distinctive heat profile, and it is worth understanding before anyone specifies a boiler for one.
most process heat is electric and stays that way
Die attach curing, molding, reflow soldering, and burn-in testing all involve heat, and in modern equipment that heat is generated electrically inside the tool, under tight closed-loop control. A boiler is not a candidate for these duties and should not be proposed for them. Temperature profiles here are part of the qualified process, and the equipment maker controls them.
This is the single most common misunderstanding when quoting for electronics facilities, and getting it wrong wastes everyone's time. The opportunity is elsewhere.
the utility loads that do need a boiler
Controlled-environment areas need humidity control for the same electrostatic-discharge reasons as a full cleanroom, and steam injection into the air handlers is the standard method. Depending on the classification and area involved, this is frequently the largest single steam load on the site.
Cleaning and rinsing stages between process steps commonly specify heated water or heated chemistry, delivered indirectly through exchangers. Facility services add the usual steady base: canteen, washrooms, gowning areas, and garment laundry, which in a controlled-environment plant is often done on site rather than sent out.
where thermal oil sometimes enters
Some equipment in this sector uses heated platens and presses, and where a plant chooses hydraulic or press-based processes with heated tooling, a thermal oil circuit can be the appropriate way to deliver stable high temperature at low pressure. It is not universal — many installations heat platens electrically — so this depends entirely on the equipment selected.
The reason it matters at the planning stage is that a thermal oil system and a steam system are different plant rooms with different piping, and discovering the requirement after the utility building is designed is expensive. Asking the equipment supplier early whether any tooling expects a heat transfer fluid supply is a five-minute question that occasionally saves a great deal.
practical advice for anyone specifying utilities for an ATP plant
Start from the air handling design, because humidification usually sets the steam requirement, and the mechanical designer will have that load before anyone else does. Add the cleaning and rinsing duties from the process layout, then the facility loads, which are predictable from headcount and shift pattern.
Size for the real total with a sensible margin rather than a padded one, and put the margin into a second unit rather than a bigger single boiler — in a plant where an environmental excursion is a documented event, a duty and standby pair is worth more than spare capacity in one machine. Our engineers are happy to work through that sizing with a project team at the design stage, well before there is anything to quote.
Quick questions
What is an ATP plant in semiconductors?
Assembly, testing and packaging: the downstream stage where finished semiconductor dies are packaged into usable components and tested. ATP plants are less capital-intensive than wafer fabrication facilities and employ more people, which is why they are usually the first stage of semiconductor manufacturing to establish in a new country.
Do assembly and packaging plants use steam boilers?
Yes, but for utilities rather than core processing. Curing, molding, reflow and burn-in are heated electrically inside the equipment. Boilers serve humidification of controlled-environment areas, heated cleaning and rinsing, and facility hot water including on-site garment laundry. Humidification is often the largest single steam load.
When would an electronics plant need thermal oil instead of steam?
Where equipment uses heated platens or presses that require stable high temperatures, thermal oil delivers them at low pressure, whereas steam at the same temperature would need very high pressure. It is equipment-dependent — many installations heat platens electrically — so confirm with the equipment supplier during design, since the two systems need different plant rooms.
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