Stiff PCB material with similar dielectric constant as FR4

Hi all,

My 1 mm FR4 board warps all over the place when heated. Do u know of a cheap PCB substrate with similar dielectric constant to FR4 but is stiffer?

Thanks

You have to compromise either on the price or the quality. Naturally you cant expect sugar at price of salt. :D
Cheers

boards normally warp because you have unequal amounts of copper on the top and bottom, so when the temperature changes the copper makes it curl up like a potato chip. You fix that by the way you layout the board (you put extra copper on the sparse side).

thanks for the replies. It's ok if it's not too expensive. It just have to be available commercially. I am however constrained by having to use double sided, single layered PCB since the final design must be lowest cost possible.

i've tried using copper fill in the more sparse copper side of the board but the warpage is still dominant. i guess this is because I am using a continuous ground plane on the bottom side so there is practically no empty copper area on the bottom side of the board. all the tracks are on the top side.

hence have u used a double sided, single layered PCB substrate that is engineered to be stiffer than usual?