I call it "ultimate" because it is not easy to get, and I have to go to many different parts of the government to get it finally usable for international travel.
First, after the birth, we got a notice on how to obtain the birth certificate from the county registrar (101 Grove St. #105, tel: 415-554-2700). It costs $16 per copy and the document can be used within US.
The later steps, not stated in the instruction and not clearly stated on the web site, were the ones I learnt through a trial-and-error procedure.
Second, I have to go to the county clerk (City Hall #168, one Dr. Carlton B. Goodlett Place, tel: 415-554-4955) to obtain its signature. It is $11 verification fee for each document. She checked the original file, print out a paper stating the document is real, signed it and stapled it to the original file. By the way, They only accept check, money order, cash and debit card. Be caution that the cash does not mean $100 bills. If you only have a $10, a $100 and credit cards, you are stuck - like me. They will suggest you to go downstair and get $100 exchange in the cafe. Don't go! The staff there will say: AGAIN? WE DON'T OFFER EXCHANGE. They will suggest you to go outside to find a bank, which I almost did. But, fortunately, I asked: is there an ATM machine in the building. Yes! There is one in a hidden corner in the building and no transaction fee applied to my credit card account! Problem finally solved. But, I had to be in line for three times: no cash - first time, no exchange from the cafe and got the ATM location - second time, process the document - third time. So, get everything ready and then go to the county clerk, because the person at the information desk of the county clerk's office was really not helping! @#$%^%&@#
Anyway, third, mail the original document, $20 check/money order/cash (pay to secretary of state), self-addressed stamp envelope and a cover letter stating the country to visit, date, contact name and phone number to SECRETARY OF STATE, NOTARY PUBLIC SECTION, PO BOX 942877, SACRAMENTO, CA 94277-0001. By the way, if you are in a hurry, you can drive to 1500 11th St. 2nd floor, Sacramento, CA 95814, 916-653-3595 to get the apostille on-site.
We, I and a friend, actually went to Sacramento directly without the county clerk signature and were told the state cannot do the apostille without the county clerk's signature. Interestingly, after knowing a birth certification only with a MD's signature is not really official on any level, my friend was able to get a copy of the birth certification from the registrar office with both the MD's signature and the county clerk's signature (of course, with extra money). Why the office don't always print both signatures on the birth certification, but let us, stupid naive first-time people, go through different departments and different buildings to scavenge the solution? It is not only wasting our time, but also those precious government employees' working time. I can see why the government will never be a small government.