I work with C8051F060 micro-controller and I
use C8051F060 DK target board, so I have
USB serial adapter too. I must put a program in my
micro-controller and then solder the chip into separate
application board.
That is plain crazy, all you need is a JTAG connector on your "separate application board".

If space is a problem you can, since this is programming, not "user use", use edge points and a heavy clamp.

The SILabs chips were never designed for off app programming and if that is what you want to do, then use a socketed chip. What will you do if - no WHEN, after shipping a load of boards, a software glitch show up. "That will not happen" is a statement that is Horsefeathers mixed with male cow manure.

Yes, what you suggest is "possible" but in my opinion plain crazy.

if you insist on continuing down this crazy route
all conditions are similar those on target board but
when I try to connect to from Silicon Laboratories IDE
i get this massage:
"Communication could not be established with the
specified serial adapter. Please confirm the current
'Connection options' selections. "
put a scope on and find out where "similar" is not "identical"

Did you connect analog power? not doing that is the "popular SILabs goof". For instance, I, on my first SILabs board did not connect analog power because I do not use analog functions, but was informed that the oscillator is powered by the analog power pins. Oddly enough, due to leakage, some boards may "work" without analog power connected, but never reliably. There has been many problem posts (in the SILabs forum) solved by pointing thai out

GET A JTAG CONNETOR ON YOUR FINAL BOARDS or switch to a socketed chip.

Erik