Preheat the oven to 400 degrees. Line a large baking sheet with parchment paper or foil.
Arrange the halibut on the prepared pan and season with salt and black pepper. Arrange the tomatoes alongside the fish. Set aside.
Melt the butter in a small saucepan over medium-high heat. When the butter is bubbly, add the wine, scallions, and thyme. Cook for 1 minute, until the sauce reduces slightly. Pour the butter sauce over the halibut fillets.
Bake for 8 to 10 minutes, until the fish is fork-tender (a meat thermometer should read 130 to 135 degrees; cooking time depends on the thickness of your fillets) and the tomatoes are blistered.