Only two phone companies don't use Qualcomm chips. That's Samsung with its own Exynos line (though they still use Qualcomm chips in the US) and Apple, making their own SoC for the iPhone and iPad. Usually Apple still has Qualcomm chips left on the iPhone but they are also moving to Intel.
See also: Apple considers putting Qualcomm chips on iPhones and iPads next year
Broadcom is paying $ 70 for a Qualcomm stock, 28% higher than Qualcomm's stock price. But that was the value of a year ago.
If the deal fails, Broadcom will become the world's third-largest chip maker, after Intel and Samsung. Qualcomm is also trying to close a $ 47 billion deal with NXP, another chip maker.