Liquid Encapsulants VS Molding Compounds

Liq­uid encap­su­lants and Epoxy mold­ing com­pounds are gen­er­al­ly two sides of the same coin. They are a ther­moset­ting mix­ture of poly­mer­ic resin, a hard­en­er and some fillers that come in both liq­uid and sol­id (pellets/powder) forms.

Semi­con­duc­tor encap­su­lants are used to 

  • Pro­tect bond­ed dies on sub­strates against mechan­i­cal and chem­i­cal impacts 
  • Pro­vide local­ized pro­tec­tion of sen­si­tive components. 
  • Act as a wire bond dielec­tric and min­i­mize corrosion
  • Sub­se­quent­ly, allow wire-bond­ed devices to pass reli­a­bil­i­ty targets.

Despite all their func­tion­al sim­i­lar­i­ties, they have some dif­fer­ences that real­ly set them apart when choos­ing your semi­con­duc­tor encap­su­la­tion method. And these dif­fer­ences are main­ly prac­ti­cal and operational.

Liquid encapsulants

Liq­uid encap­su­lants are dis­pens­able mate­ri­als that are pre­ferred for flex­i­ble, lab-scale projects that need con­stant changes and align­ments. They are using an easy and cheap dis­pens­ing sys­tem that is ide­al for flex­i­ble projects with low­er through­put. Research, devel­op­ment, and advanced pack­ag­ing are def­i­nite­ly favor­ing this liq­uid encap­su­la­tion that facil­i­tates innovation.

The mate­r­i­al itself is (Kg to Kg) slight­ly more expen­sive but the set up invest­ment cost is min­i­mal and can be used for mul­ti­ple projects.

On top of that, liq­uid encap­su­lants can cure in much low­er temperatures(enabling sen­si­tive com­po­nents) and can achieve flat­ter and thin­ner pack­ages. The high­est that you can go if you stack mul­ti­ple dams is some­thing around 1mm. All these aspects along with the min­i­mal wire sweep lead the charge towards minia­tur­iza­tion and makes them the encap­su­la­tion mate­ri­als of the future.

Epoxy molding compounds 

Epoxy mold­ing com­pounds are, as the name implies, mold­able mate­ri­als. They are com­mon­ly used with trans­fer (and rarely com­pres­sion) mold­ing. Trans­fer mold­ing is a fixed, con­trolled, and expen­sive process. You need very spe­cif­ic mold designs and sophis­ti­cat­ed equip­ment that can only be used for a sin­gle pack­age. This makes this process com­plete­ly rigid and requires a very large ini­tial invest­ment and a def­i­nite pack­age design.

These mate­ri­als cure in high­er tem­per­a­tures and because of the way the trans­fer process works, they make larg­er and thick­er pack­ages. Final­ly, because of the trans­fer pres­sure and the epoxy flow through the gate­ways, the pack­ages are prone to wire sweep.

But it is not all dark and gloomy. Mold­ing com­pounds are cheap­er than their liq­uid forms and once the equip­ment is set up the over­all process becomes cheap­er and poten­tial­ly faster. That’s why trans­fer mold­ing is ide­al for stan­dard­ized and final­ized mass pro­duc­tion packages.

So why would any­one choose mold­ing com­pounds over liq­uid encap­su­la­tion? Well, it is not a con­test and these are mate­ri­als for very dif­fer­ent appli­ca­tions. To sum­ma­rize, small pro­duc­tions, flex­i­ble design and low­er cure temp favor liq­uid encap­su­lants. Mass pro­duc­tion, rigid design and high­er cure temp favor mold­ing compounds.

Liq­uid encap­su­lants such as Henkel’s SVHC Free 7010C DAM FIL are used for Chip on board or wafer lev­el encap­su­la­tions (LCM1000AF). Semi­con­duc­tor mold­ing com­pounds such as Hysol’s GR750 and GR9810-1PF on the oth­er hand are the way to mass-pro­duce mil­lions of Sen­sors, TO, DIP, QFN and high pow­er pack­ages. Very dif­fer­ent needs for very dif­fer­ent nich­es and designs.

Opti­cal­ly clear mate­ri­als exist for both cat­e­gories. Opto­elec­tron­ic mold­ing com­pounds such as TC-8020T are already used in bio­met­ric and opti­cal emit­ters and trans­mit­ters. Clear liq­uid encap­su­lants like OLS-1211 are used for LED pot­ting or glob top opti­cal encapsulation.

Liq­uid encap­su­la­tion on lam­i­nate is lead­ing the way while trans­fer mold­ing is main­tain­ing the bil­lions of cur­rent­ly pro­duced sin­gled-out lead­frame pack­ages. Both are cru­cial for the advance­ments in tech­nol­o­gy and electronics.

Do you have an appli­ca­tion and you are not sure what process to choose? You know your process but you can­not choose a prop­er mold­ing com­pounds or liq­uid encap­su­lants? Please con­tact us and we will take you through the steps to iden­ti­fy or even devel­op a prod­uct that per­fect­ly fits your appli­ca­tion requirements.

About George Kountardas

George is a Jack of all trades with an unappeasable inquiring mind. Obsessed with new products and technologies, he is always pushing forward for better, faster and more efficient applications. Always learning something new.

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