Supramaximal training – lifting from the sticking point of a lift with weight greater than your max – is a great tool to break through the phase of the lift that you struggle with most. An example of this would be training the top half of your squat if you get stuck after you're out of the hole.
This is an important concept because strength is specific to a joint angle. This is why your squat isn't exactly the same if you bring your feet in two inches or point your toes out more. Each small tweak changes the angles of the joints which changes how muscles fire. It's essential that you work the partial range of motion from your sticking point to get stronger.
Make sure you're setting up with the same position that you'd be in during your sticking point, use the same grip and stance width to maximize strength gains.