Plating thickness of 0.3mm drill via? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: January 17, 2024, 06:58:16 pm
content: Hi,Doing a dense PCB, and using loads of 0.6mm/0.3mm (0.3mm drill) vias as its all i can fit in.I need to find the via resistance, and so therefore i need to know the playing thickness inside the via.The board is 1.6mm thick and 4 layer and we request 20z copper (70um).However, as you know, you ony get 2oz on the top and bottom, the inner layers end up being just one ounce, for a PCBquoted as being "2oz".Anyway, PCBWAY, in their web page, only quote plating thickness for 2oz copper. So presumbly that includes us?PCBWAY say that plating thickness inside a via is only 18-25um from "standard process"....and is 30-50um with "medium difficulty",and >50um with "High difficulty".Anyway, what plating thickness do you think we could get in our 0.6mm/0.3mm vias?I am pretty certain that the smaller the via diameter, the less is the plating thickness that can be acheived with it, though PCBWAY dont elaborate?Though i appreciate , for more cost, one can elect to put ones manufactured PCB back into the plating bath to thicken up thevia barrels. But that more than doubles the cost of the board?https://www.pcbway.com/capabilities.html

author: jpanhalt
author_rank: Super Contributor
timestamp: January 17, 2024, 08:34:44 pm
content: Have you even considered asking your eager PCB provider those questions?

author: SeanB
author_rank: Super Contributor
timestamp: January 17, 2024, 10:36:07 pm
content: Take it that the plating will always be at the minimum thickness, and add more vias if that is not enough.

author: jc101
author_rank: Frequent Contributor
timestamp: January 17, 2024, 10:39:30 pm
content: PCBWAY offer 2oz inner layers, too, if you want them.Design for a plating of 18-20um, then you're covered. I vaguely remember that under IPC-6012, classes 1 & 2 give 20um or more and no less than 18um. Class 3 is 25um average thickness or more and not less than 20um.The bottom line is that only the PCB manufacturer can give you that data. Perhaps they will section a test piece and measure it for you?

author: Faringdon
author_rank: Super Contributor
timestamp: January 18, 2024, 07:16:54 am
content: Thanks, its pretty terrible that all you get is 18um...i mean, thats half ounce copper....and the board is quoted at 20z.(This isnt just PCBway, its all of them)

author: selcuk
author_rank: Frequent Contributor
timestamp: January 18, 2024, 07:33:24 am
content: There is a copper paste filling method. But I have never ordered it since it is too expensive.

author: Faringdon
author_rank: Super Contributor
timestamp: January 18, 2024, 07:40:12 pm
content: Thanks, it just worries me that the standard plating you get on a 0.3mm drill via on a 2oz board is something like 8um?

author: jc101
author_rank: Frequent Contributor
timestamp: January 18, 2024, 07:42:28 pm
content: Quote from: Faringdon on January 18, 2024, 07:40:12 pmThey quote a min of 18um, where did the 8 come from?Did the PCB company specifically state it could be a low as 8um? If so, go somewhere else.

author: thm_w
author_rank: Super Contributor
timestamp: January 18, 2024, 09:53:24 pm
content: Quote from: jc101 on January 18, 2024, 07:42:28 pmtypo

author: Faringdon
author_rank: Super Contributor
timestamp: January 19, 2024, 06:48:08 am
content: Thanks, but i have heard that small vias get less plaing thickness...but have lost the document, and wondered if anybody knew?

author: jpanhalt
author_rank: Super Contributor
timestamp: January 19, 2024, 08:49:33 pm
content: Quote from: Faringdon on January 19, 2024, 06:48:08 amNonsense. I just asked JLCPCB this:Presumably, you could order a thicker plating.

author: langwadt
author_rank: Super Contributor
timestamp: January 19, 2024, 09:35:50 pm
content: Quote from: jc101 on January 17, 2024, 10:39:30 pmhttps://www.epiccolo.com/articles/pcb-vias-guide#barrel-and-aspect-ratio