Why capacitors?

A few weeks ago, we proudly announced that we had star­ted pro­duc­tion of capa­cit­ors in high-volume. But why the fuss about capa­cit­ors? After all, it is a severely price-pres­sured and already cheap com­mod­ity. And why is Smol­tek’s divi­sion for the semi­con­duct­or industry, Smol­tek Semi, doing this? A capa­cit­or is not a semi­con­duct­or! And what’s the plan for the future? All this is the sub­ject of this week’s blog post.

One of the toughest markets in the world

Yes, capa­cit­ors are a com­mod­ity. Yes, capa­cit­ors are cheap (they cost apiece just a frac­tion of a dol­lar). And yes, capa­cit­ors are under severe price pres­sure from the big boys.

So what on earth makes a small com­pany up in the north, not yet prof­it­able, bet on what must be one of the toughest mar­kets in the world?

The answer is two-fol­ded: The know-how to solve one of the elec­tron­ic industry’s biggest prob­lems in the con­tin­ued devel­op­ment of increas­ingly power­ful small devices. And the busi­ness oppor­tun­ity that comes with that know-how.

Let’s unpack what this means, start­ing with the busi­ness opportunity.

Why all the fuss about capacitors?

Every device that con­tains chips also con­tains capa­cit­ors. Your smart­watch, smart­phone, smart speak­er; your tab­let, laptop, and desktop com­puters; your tv, ste­reo sys­tem, and robot vacu­um clean­er. Every elec­tron­ic gad­get you own. The same applies to lar­ger sys­tems like cars, med­ic­al devices, and indus­tri­al-pro­cess controllers.

In short, capa­cit­ors can be found every­where. They are omni­present. And there is a colossal demand for them. Every year, more than a whop­ping one tril­lion capa­cit­ors are pro­duced worldwide.

Smol­tek aims to grab a slice of that pie.

Huge market

It sounds like the hubris of a star­tup when Smol­tek claims to be able to cut even a slice of the pie. But it’s any­thing but hubris.

As you know, we have partnered with YAGEO, the world’s third-largest man­u­fac­turer of pass­ive com­pon­ents like capa­cit­ors. With our know-how and YAGEO’s sales and dis­tri­bu­tion chan­nels, we aim to jointly cap­ture one-third of the capa­cit­or mar­ket for the premi­um seg­ment of mobile phones except iPhones.

Of course, Apple knows what we have to offer, but we don’t pur­sue them for now. They are work­ing closely with a com­pet­it­or, and we believe they will not jump ship any time soon. 

We estim­ate that our address­able mar­ket buys between 3.5 and 4.5 bil­lion capa­cit­ors each year. So even if the price apiece is only a frac­tion of a dol­lar, the over­all sales impact is impressive.

Not a semiconductor

It may seem strange that Smol­tek focuses on an elec­tron­ic com­pon­ent that is not a semi­con­duct­or. But there is a per­fect reas­on for that. I have already hin­ted at what it is:

Capa­cit­ors are an abso­lute neces­sity for digit­al integ­rated cir­cuits of semi­con­duct­ors to work.To explain why, we need to go down the rab­bit hole of the inner work­ings of integ­rated cir­cuits and capa­cit­ors. If you don’t like the won­der­land of elec­tron­ics, skip this part and go straight to the last ques­tion: What’s the endgame?

Still here?

Good! Let’s fol­low the White Rabbit.

Transients

Although semi­con­duct­ors can be used for more than just digit­al integ­rated cir­cuits, digit­al integ­rated cir­cuits, or chips for short, are what we’re talk­ing about here. A chip con­sists of tran­sist­ors that act as elec­tric­al switches. Each tran­sist­or rep­res­ents a bit – a num­ber that can be one or zero. A tran­sist­or turns on power to rep­res­ent the value one and turns off power to rep­res­ent the value zero.

Turn­ing the power on and off can affect nearby devices. You may have exper­i­enced that the lights in your home blink when you turn on or off a kettle or oth­er elec­tric­al appli­ance that draws a lot of power. This is because the rap­id change in power demand cre­ates a short-lived pulse, called a tran­si­ent, which propag­ates from the appli­ance, through the wir­ing, to the lights. The same hap­pens when tran­sist­ors in a chip turn power on and off.

Troublesome transients

To make mat­ters worse, tran­sist­ors on a chip turn on or off sim­ul­tan­eously. They do so at the beat of a clock that ticks bil­lions of times every second. Each tran­sist­or con­trib­utes a little to what adds up to a sig­ni­fic­ant tran­si­ent. This tran­si­ent will propag­ate from the chip to oth­er chips and com­pon­ents if not addressed. That can dis­rupt (and even des­troy) the elec­tron­ics, with dev­ast­at­ing consequences.

Not only that. Tran­si­ents rush­ing through the power-feed­ing tracks make them act as trans­mit­ting anten­nas that send out radio waves. Oth­er tracks act as receiv­er anten­nas that pick up the radio waves and con­vert them into elec­tri­city. This way, the pulse is trans­mit­ted wire­lessly from the sup­ply tracks to oth­er tracks. Tracks that may trans­mit ones and zer­os that are at risk of flip­ping. Again, the con­sequences can be devastating.

Why capacitors are a necessity for semiconductors

To pre­vent these dev­ast­at­ing con­sequences, mit­ig­at­ing out­go­ing and incom­ing tran­si­ents is neces­sary. This is where capa­cit­ors come into play. When a capa­cit­or is used for this pur­pose, it’s called a decoup­ling capa­cit­or.

You can think of a decoup­ling capa­cit­or as a shock absorber for the voltage sup­ply to the chip. Quick voltage changes, both upward and down­ward, are smoothed out and become much smal­ler. They do this by absorb­ing and releas­ing energy as the sup­ply voltage fluctuates.

Some capa­cit­ors are light­ning-fast at absorb­ing the energy but can­not absorb much. Oth­ers are slower but can absorb more. There­fore, sev­er­al capa­cit­ors are often needed to pro­tect a chip. A single smart­phone pro­cessor today typ­ic­ally has eight decoup­ling capacitors.

That’s why capa­cit­ors are neces­sary for semi­con­duct­ors and the semi­con­duct­or industry. How­ever, the decoup­ling capa­cit­ors must be as close to the chip as pos­sible for it to work.

Why capacitors need to be close to the chip

In an ideal world, capa­cit­ors respond light­ning-fast to power surges, but in real­ity, they don’t. The reas­on is spelled para­sit­ic induct­ance.

Induct­ance refers to the prop­erty of an elec­tric­al con­duct­or by which a quick change in cur­rent flow­ing through it induces (hence the name) a voltage that opposes this change, effect­ively slow­ing the rate at which cur­rent can change.

Unin­ten­tion­al and unwanted induct­ance is said to be para­sit­ic. Para­sit­ic induct­ance is every­where, even in the wires between the capa­cit­or and the chip. The longer the wires, the more induct­ance and the great­er the res­ist­ance to sud­den changes. That is the oppos­ite of what we want to achieve.Thus, keep­ing the wires between a decoup­ling capa­cit­or and its chip as short as pos­sible is essen­tial. Ideally, the capa­cit­or should be inside the chip. But the next best thing for decoup­ling capa­cit­ors is to sit between solder balls under the chip. Such a capa­cit­or is called a land-side capa­cit­or (LSC).

Why capacitors need to be thin

It should be pretty obvi­ous why land­side capa­cit­ors must be small. They com­pete with the solder balls for space on the under­side of the chip. The typ­ic­al length and width of a capa­cit­or vary between half and a few millimeters.

They must also be thin because the dis­tance between the chip and the cir­cuit board is smal­ler than the dia­met­er of the solder balls. Com­monly, for com­puter chips, the solder balls are only 0.5 or 0.4 mil­li­meters in diameter.

In premi­um smart­phones, the require­ments are much tough­er than that. They require ultra-thin capa­cit­ors. We are talk­ing about tens of micro­met­ers instead of millimeters.

Challenges with ultra-thin capacitors

When the thick­ness of a land-side capa­cit­or gets down to 80 micro­met­ers, 60 micro­met­ers, or even 40 micro­met­ers, many prob­lems start to creep up.

The first chal­lenge that man­u­fac­tur­ers face is capa­cit­ance. This is the abil­ity to save energy. It is neces­sary to cre­ate suf­fi­cient capa­cit­ance in the small area avail­able without mak­ing the capa­cit­or too high.

Anoth­er chal­lenge for man­u­fac­tur­ers is to cre­ate ultra-thin capa­cit­ors that are not so brittle that they can­not be handled indus­tri­ally without breaking.

A third chal­lenge is the strength of mater­i­als. One tech­nique used today is to fill etched trenches in sil­ic­on sub­strates with an insu­lat­ing mater­i­al. How­ever, there are lim­it­a­tions in how deep these trenches can be and how tightly they can be placed.

Fourth, last but not least, these chal­lenges make the research and devel­op­ment of ever-thin­ner capa­cit­ors more com­plex and their pro­duc­tion more expensive.

This is where Smoltek’s CNF-MIM capa­cit­ors enter the stage.

What makes CNF-MIM capacitors unique

We expect CNF-MIM capa­cit­ors to have high­er capa­cit­ance than a deep trench sil­ic­on capa­cit­or (the closest com­pet­it­or) of the same length, width, and height.

In addi­tion, the CNF-MIM capa­cit­or is expec­ted to meet real-world require­ments with fly­ing col­ors: excel­lent capa­cit­ance sta­bil­ity, high break­down voltage, low leak­age cur­rent, and low series res­ist­ance and inductance.

To top it off, CNF-MIM capa­cit­ors aimed at high-end device seg­ments are expec­ted to be cheap­er to pro­duce, so we can com­pete on price and still have a good mar­gin for capacitors.

The endgame

Is the com­mer­cial­iz­a­tion and mass pro­duc­tion of CNF-MIM capa­cit­ors the endgame of Smoltek’s explor­a­tion in the semi­con­duct­or territory?

No.

CNF-MIM capa­cit­ors are just one of many applic­a­tions in the semi­con­duct­or field for which car­bon nan­ofibers can be used. If you’ve been around for a while, you might remem­ber Smol­TIM, SmolINCO, and SmolINPO. Our pat­ent-pro­tec­ted solu­tions for heat dis­sip­a­tion inside chips, inter­posers with built-in decoup­ling capa­cit­ors and rein­forced con­nec­tion points for mul­tiple dies, and solder balls with ultra-fine pitch (down to 5 micrometers).

How­ever, we chose CNF-MIM capa­cit­ors because it was pretty obvi­ous busi­ness-wise. There is an immin­ent need for ultra-thin capa­cit­ors, and the mar­ket is vast.

Our pat­ents pro­tect the oth­er tech­no­lo­gies, so we can safely focus on launch­ing sales and rolling out mass pro­duc­tion of CNF-MIM capa­cit­ors. Once it is up and run­ning, we can return to the oth­er tech­no­lo­gies and con­sider which one to bring to the mar­ket next.

Unequivocal proof of concept

Anoth­er bene­fit of start­ing with pro­du­cing CNF-MIM capa­cit­ors is that it offers unequi­voc­al proof for foundries that our tech­no­logy works in their environments.

Foundries are the factor­ies that make the semi­con­duct­or itself. They are argu­ably the most expens­ive factor­ies humans have ever built. Each costs sev­er­al bil­lion US dol­lars. Thus, their own­ers and investors don’t take any risks. They can’t afford it.

It is too risky for them to insert Smol­tek’s car­bon nan­ofiber grow­ing tech­no­logy into their CMOS chip man­u­fac­tur­ing pro­cess without proof that it works.

Now they get that proof.

The same tech­no­logy used by foundries makes the CNF-MIM capa­cit­ors. Of course, with the addi­tion of our car­bon nan­ofiber growth tech­no­logy. And that’s the point. Our tech­no­logy works with theirs without caus­ing any problems.

Over to you

Well, that’s pretty much all there is to know about why we chose capa­cit­ors as the first com­mer­cial­ized applic­a­tion of car­bon nanofibers.

What do you think of the blog post? Was it too long? Too tech­nic­al? Or maybe just right? Some­thing you have missed? Head over to Linked­In and leave a comment.