It depends. Sometimes Batman is responsible for creating super-villains himself, sometimes he creates them indirectly and sometimes he doesn't have anything with it . Here are examples of all three
In New52 comics "Batman: Zero Year" he and Red Hood fought and Red Hood fell in chemicals thus creating Joker. Here Batman is personally responsible for creating Joker
What has remained the most consistent is that his first encounter with
the Batman was while he was acting in the identity of the "Red Hood,"
along with a gang of other thugs, committing a robbery in or near the
Ace Chemical Processing Plant. During this robbery he either tripped
into a vat of chemicals, or was accidentally pushed in by Batman.
Poison Ivy was on other hand created indirectly by Bruce Wayne in "Batman: Zero Year"
Bruce Wayne came to look in on Pamela's division when she took the
opportunity to present him with a business project that would cut his
advertising division by 100%. In fact, she had used pheromones to get
the meeting with him, and this was her proof that Wayne Enterprises
could use pheromones to target clients, and modify their behaviour to
the company's benefit. Wayne refused her pitch on the grounds that it
amounted to brainwashing, and removed free choice from the equation.
Ethically opposed to her idea, Bruce Wayne fired her on the spot,
warning that his company owned any research she had done, so she would
not be able to pitch her idea elsewhere.
Angrily, she had rushed past security to steal what she could of her
work back, specifically a plant serum that she had made from all of
her knowledge in botanical research, which she alone knew how to
make. Unfortunately, in the process, she was doused with her own
chemicals. The chemicals changed her, making her immune to poisons and
viruses, giving her command over any plant,
As for Scarecrow, his father is mostly responsible for his creation.
When Jonathan Crane was a child, his father conducted many
experiments, trying to comprehend the emotion of fear. Unable to use
proper test subjects, Dr. Crane used Jonathan as his guinea pig.As
part of the experiments, Jonathan was locked inside a little dark room
while his father examined the test's effects on his son. One day
however, during one of the experiments, Dr. Crane experienced a heart
attack and died, leaving young Jonathan still trapped in the pitch
black test chamber.
As a result of this event, he was traumatized most of his childhood
until, eventually, Jonathan decided that if he could control fear, he
would never have to live in it again. He soon developed an obsession
with his goal and became a psychologist with a concentration in
phobias. Not waiting long to put his degree to use, Crane began using
patients as test subjects to develop a project that he would later
call "Fear Toxin". The gas, when inhaled, would cause his victims to
hallucinate about their worst fears.
Crane, adopting the alias "the Scarecrow", soon became a threat to
Gotham City, as he took criminal measures to perfect his fear gas.
This is of course all happening in New 52 universe
