PHP授权NTLM

I am trying to get data from service. Here is my code:

$opts = array(
   'http'=>array(
      'header'=> 'Authorization: Basic '.base64_encode('$uN:$pW')
   )
);
$context = stream_context_create($opts);
 $result = file_get_contents(
     'https://.........',
     false,
     $context
 );

This code causes exception -

Request filed. Unauthorized 401

I tried access this link from browser. Browser asked for credentials and requested with header "Authorization: NTLM ....". I replaced "Basic" with "NTLM", but nothing changed and code keeps fail. Maybe someone know where is the problem?