A method of forming a semiconductor package structure comprising a plurality of dies (120, 124, 128; 320, 324, 328) stacked between a substrate (110, 310) and a heat sink (180, 380), the dies forming a stack and being separated from one another by interlayer dielectric layers (118, 122, 126, 130; 318, 322, 326, 330), the method comprising: patterning and etching a plurality of through-silicon via openings in each of the dies (120, 124, 128; 320, 324, 328), the plurality of through-silicon via openings comprising: a first through-silicon via opening (131, 132, 340, 341, 342) that extends through the entirety of each of the dies (120, 124, 128; 320, 324, 328) without penetrating any active circuit region, A1, A2, AN, formed in the die, and a second through-silicon via opening (133 - 138, 350, 351, 360, 361, 370 - 373) that extends down to, but not through, any active circuit regions, A1, A2, AN, formed in the die, such that in the stack the aligned second through-silicon via openings extend through one or more dies without interruption, down to a die in the stack where a lowest second through-silicon via opening stops in order to not extend through or below any active circuit region; and forming one or more conductive layers in the first plurality of through-silicon via openings to form a first plurality of through-silicon via structures in the semiconductor package structure for thermally conducting heat; and stacking the dies onto one another such that the first through-silicon via openings (131,132, 340, 341, 342) in each die are aligned and extend through all of the dies between the substrate (110, 310) and the heat sink (180, 380), wherein the dies are stacked and bonded; wherein patterning and etching the plurality of through-silicon via openings comprises, for each die: depositing a photoresist layer over the die; patterning and anisotropically etching the photoresist layer to form an etch mask for the die comprising a first pattern opening for the first through-silicon via opening that is larger than a second pattern opening for the second through-silicon via opening; and selectively and anisotropically etching the die using the etch mask to extend the first through-silicon via opening through the die without penetrating any active circuit region, and to extend the second through-silicon via opening down to, but not through, any active circuit regions formed in the die. a first through-silicon via opening (131, 132, 340, 341, 342) that extends through the entirety of each of the dies (120, 124, 128; 320, 324, 328) without penetrating any active circuit region, A1, A2, AN, formed in the die, and a second through-silicon via opening (133 - 138, 350, 351, 360, 361, 370 - 373) that extends down to, but not through, any active circuit regions, A1, A2, AN, formed in the die, such that in the stack the aligned second through-silicon via openings extend through one or more dies without interruption, down to a die in the stack where a lowest second through-silicon via opening stops in order to not extend through or below any active circuit region; and forming one or more conductive layers in the first plurality of through-silicon via openings to form a first plurality of through-silicon via structures in the semiconductor package structure for thermally conducting heat; and stacking the dies onto one another such that the first through-silicon via openings (131,132, 340, 341, 342) in each die are aligned and extend through all of the dies between the substrate (110, 310) and the heat sink (180, 380), wherein the dies are stacked and bonded; wherein patterning and etching the plurality of through-silicon via openings comprises, for each die: depositing a photoresist layer over the die; patterning and anisotropically etching the photoresist layer to form an etch mask for the die comprising a first pattern opening for the first through-silicon via opening that is larger than a second pattern opening for the second through-silicon via opening; and selectively and anisotropically etching the die using the etch mask to extend the first through-silicon via opening through the die without penetrating any active circuit region, and to extend the second through-silicon via opening down to, but not through, any active circuit regions formed in the die. depositing a photoresist layer over the die; patterning and anisotropically etching the photoresist layer to form an etch mask for the die comprising a first pattern opening for the first through-silicon via opening that is larger than a second pattern opening for the second through-silicon via opening; and selectively and anisotropically etching the die using the etch mask to extend the first through-silicon via opening through the die without penetrating any active circuit region, and to extend the second through-silicon via opening down to, but not through, any active circuit regions formed in the die.