You should create a FieldLikePredicate with CaseSensitiveCollection=true. Example:
var likePredicate = new FieldLikePredicate(EmpFields.EmpName, null, theName.ToUpper());
likePredicate.CaseSensitiveCollation = true;
var filter = new RelationPredicateBucket();
filter.Add(likePredicate);
adapter.FetchEntityCollection(employees, filter);