Issue link: https://iconnect007.uberflip.com/i/1207026
32 SMT007 MAGAZINE I FEBRUARY 2020 so that you have the maximum volume. SPI would help. Matties: Is that a standard practice now in most shops? Prasad: Not for everybody. It depends. If you buy a $50,000 printer, it's not going to have SPI capability. I also want to mention that the most important capability you need in a printer is the ability to suck solder out of the stencil aperture. When the pitches get smaller, you want to ensure that nothing gets stuck in there. As the pitches get smaller, it becomes harder and harder to meet that requirement. The capability to suck solder out of small aper- ture is available mostly in more expensive printers (100,000+), and not everybody has such printers. Matties: For the fine pitch, you said placement isn't an issue or should be a non-issue. Prasad: For most people, the placement is not an issue because most machines are a lot better than they used to be; even if you are off, you are allowed to be off by 50% for Class 1 and 2, and for Class 3, you are allowed to be off by 25%. You don't have to be per- fect, and self-centering takes place. When the solder melts, it will pull back in, even if it's a little bit off. Matties: Are you talking about a standard sub- tractive process? Prasad: Yes. I don't think additive processes are common at this time. Matties: Where do you see the fine pitch being utilized, and how ubiq- uitous will this be in the world of electronics? Prasad: Nobody wants to buy a big phone. Wherever you need small size and weight, that's where the fine pitch has to be. We are also achieving more shrink- age by the adoption of area array packages, such as BGAs. For example, if you convert a 0.5-mm pitch QFP to a BGA, the pitch will become 1 mm, and the size will become smaller because you are using the entire bottom side of the package. In addition, when you use 1-mm pitch package instead of 0.5-mm, your printing doesn't become a problem. If you use ultra-fine pitch packages, such as 10 mils, you will have not only a printing prob- lem, but a major handling problem as well because the leads would be so fragile. That's the other part of the reason the problem hap- pens—not the printing—because when the leads are that fragile, they will cause mechani- cal problems before you get to placement. For ultra-fine pitch, the placement becomes more important. The way to talk about that is not in terms of pitch, but pitch and what kind of package. If it's a very fragile package where the leads are only on the periphery (QFP), then handling and placement will become critical. But if the same package is in a BGA or BTC, you can drop it on the floor, and nothing hap- pens because they're very robust. It depends on the package. Feinberg: Some devices, but not many, have no circuit boards. In other words, the entire device is on the chip and the connection between the chip and the user is done wirelessly, as well as the controls; there are no circuit boards in it. I got to see some this week at CES. Prasad: Look at the stocks and the PE ratios between hardware and software companies. With hardware, if you're hitting a limit, some of it can be addressed with software or AI.