Patent EP-3709342-A1 (EP)
Inventor: HARTMANN STEFFEN
IPC: H01L21/603
Filed: 2019-03-12
Abstract: An arrangement for joining two joining members (10, 20) comprises a first part (41) comprising a support surface (400), a first carrier element (60) configured to carry at least one foil (50, 51), a transportation unit configured to arrange the first carrier element (60) with at least one foil (50, 51) arranged thereon in such a way that the at least one foil (50, 51) is arranged above the support surface (400) of the first part (41) in a vertical direction (y), and a second part (42) configured to exert pressure to a joining stack, when the joining stack is arranged on the support surface (400). The joining stack comprises a first joining member (10) arranged on the support surface (400), a second joining member (20) arranged on the first joining member (10), and an electrically conductive connection layer (30) arranged between the first joining member (10) and the second joining member (20). When pressure is exerted to the joining stack by the second part (42), the at least one foil (50, 51) is arranged between the second part (42) and the joining stack and is pressed onto the joining stack, and the joining stack is pressed onto the first part (41), thereby compressing the connection layer (30) and forming a substance-to-substance bond between the first and the second joining member (10, 20), e.g. a sintered connection. The first joining member (10) may be a semiconductor substrate and the second joining member (20) may comprise a semiconductor body, including a semiconductor component. When the at least one foil (50, 51) carried by the first carrier element (60) is arranged above the support surface (400), and before pressure is exerted to the joining stack by the second part (42), a first foil (51) of the at least one foil (50, 51) that is arranged closest to the joining stack may be arranged at a first distance (d1) from an uppermost surface of the joining stack, with d1 > 0. The first carrier element (60) may comprise fastening or holding means (61) that are configured to hold the at least one foil (50, 51) in place, when the at least one foil (50, 51) is arranged on the first carrier element (60). The arrangement may further comprise a second carrier element (44) configured to carry the joining stack before arranging the joining stack on the support surface (400) of the first part (41), wherein, when the at least one foil (50, 51) is arranged above the support surface (400) of the first part (41), the first carrier element (60) may be arranged on the second carrier element (44). The arrangement may also comprise holding elements (45) that are configured to be arranged on the first part (41), and, when the first carrier element (60) is arranged in a final resting position on the first part (41), the holding elements (45) are arranged between the first carrier element (60) and the first part (41), wherein the holding elements (45) may be configured to hold down the first joining member (10) on the support surface (400) in the vertical direction (y). The at least one foil (50, 51) may comprise at least one of a compensation foil (50) (e.g., silicone heat-resistant rubbery or rubber material, or an elastomer that is resistant to heat at least up to temperatures between 150°C and 250°C) that is configured to evenly distribute a pressure exerted by the second part (42) over the joining stack and a protective foil (51) (e.g., an inert polymer or a polyimide) that is configured to prevent contaminants from contaminating the joining members (10, 20). It is also possible to attach a compensation foil (50) or parts of a compensation foil (50) to the second part (42). Forming the substance-to-substance bond between the first and the second joining member (10, 20) may be performed in a process chamber (100) comprising one or more sub-chambers (101, 102, 103), wherein either the joining stack and the first carrier element (60) with the at least one foil (50, 51) are both assembled and transferred into a first sub-chamber (101), wherein a defined atmosphere is generated in the first sub-chamber (101) and the joining stack and the foil stack are subsequently transferred to a second sub-chamber (102), wherein the joining process is performed in the second sub-chamber (102); or the joining stack is assembled and transferred into a first sub-chamber (101), wherein a defined atmosphere is generated in the first sub-chamber (101), the first carrier element (60) with the at least one foil (50, 51) is assembled in a third sub-chamber (103), and the joining stack and the first carrier element (60) with the at least one foil (50, 51) arranged thereon are subsequently transferred to a second sub-chamber (102), wherein the joining process is performed in the second sub-chamber (102).