APPARATUS FOR ESPECIALLY THERMALLY JOINING MICRO-ELECTROMECHANICAL PARTS

Abstract

The invention relates to an apparatus for especially thermally joining micro-electromechanical parts (2, 3) in a process chamber (8), comprising a bottom support plate (11) for holding at least one first (2) of the parts (2, 3) to be joined, and a pressing device (15) for applying pressure to at least one second (3) of the parts (2, 3) to be joined in relation to the at least one first part (2). The pressing device (15) is equipped with an expandable membrane (19) provided for entering in contact with the at least one second part (3). Fluid pressure, in particular gas pressure, can be applied to said membrane (19) on the side thereof facing away from the parts (2, 3) to be joined.

Claims

1. An apparatus for especially thermally joining micro-electromechanical components (2, 3) in a process chamber (B) with a lower support plate (11) for receiving at least one first component (2) of the components (2, 3) to be joined and with a pressing device (15) for applying pressure onto at least one second component (3) of the components (2, 3) to be joined, in direction of the least one first component (2), characterized in that said pressing device (15) is formed with an expandable membrane (19) provided for contacting the at least one second component (3), wherein fluid pressure, in particular gas pressure, can be applied onto said membrane (19) on its side facing away from the components (2, 3) to be joined.

2. The apparatus according to claim 1, characterized in that the membrane (19) is made of a gas-tight sheet material, in particular a rubberlike material.

3. The apparatus according to claim 1 or 2, characterized in that the thickness of the membrane (19) and its expansibility are preferably selected according to the topography of the components (2, 3) to be joined such that the membrane (19), in the contacting operating condition, applies at least approximately the same contact pressure onto the components (2, 3), regardless of any differences in height existing between them.

4. The apparatus according to any one of claims 1 to 3, characterized in that the membrane (19) extends over a pressure plate (16), which is arranged at least substantially plane-parallel to the support plate (11) and displaceable at least perpendicular thereto, wherein a pressure medium can be supplied between the membrane (19) and the pressure plate (16) so that the membrane (19) bulges towards the components (2, 3) to be joined.

5. The apparatus according to any one of claims 1 to 4, characterized in that the membrane (19) is attached, in a secure and sealed manner, by its edge region to the pressure plate (16) by means of a holding and fixing device (20).

6. The apparatus according to any one of claims 1 to 5, characterized in that the holding and fixing device (20) comprises a clamping ring (21), which extends, in particular, around the circumference of the membrane (19) and allows the membrane (19) to be fixed to the pressure plate (16) and/or to an interposed sealing device (22).

7. The apparatus according to any one of claims 1 to 6, characterized in that a negative pressure can be applied onto the membrane (19) on its side facing away from the components (2, 3) to be joined, in particular in the non-contacting operating condition of the membrane (19).

8. The apparatus according to any one of claims 1 to 7, characterized in that a heating device (12, 14) is provided above the pressure plate (16) and/or below the support plate (11).

9. The apparatus according to any one of claims 1 to 8, characterized in that the support plate (11) is provided as a heating plate.

10. The apparatus according to any one of claims 1 to 9, characterized in that the process chamber is provided as a vacuum chamber (8) with a sealed housing (4) and with at least one opening (9) of the housing (4) that is provided for deaeration/evacuation and aeration/gasifying of the vacuum chamber (8).

11. The apparatus according to any one of claims 1 to 10, characterized in that by means of a control device (24) at least the fluid pressure of the pressing device (15) can be adjusted according to the selected process, in particular a TLPS (transient liquid phase soldering) process or a TLPB (transient liquid phase bonding) process or a sintering process, and according to the topography of the components (2, 3) to be joined.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] An exemplary embodiment of an inventive apparatus for thermally joining semiconductor chips to a carrier is shown in the drawings in a schematically simplified manner and will be explained in more detail below.

[0037] In the drawings:

[0038] FIG. 1 shows a simplified three-dimensional front view of an apparatus for thermally joining semiconductor components, said apparatus comprising a vacuum chamber, and

[0039] FIG. 2 shows another three-dimensional view of the apparatus of FIG. 1 in longitudinal section.

EMBODIMENTS OF THE INVENTION

[0040] FIGS. 1 and 2 show an apparatus 1 for thermally joining first micro-electromechanical components 2 to second micro-electromechanical components 3, wherein said first components 2 are Si chips of different heights and said second components 3 are Cu carriers in this case.

[0041] The apparatus 1 comprises a two-part housing 4, which can be opened and closed by a swivel mechanism 5 and can be sealed to the environment by sealing devices 6, 7. A process chamber 8 formed within the housing 4 is presently embodied as a vacuum chamber with an opening 9 for deaeration or evacuation and aeration or introduction of gas, respectively, of the vacuum chamber.

[0042] In the process chamber, a support plate 11 for the first components 2 in the form of Cu carriers and for the Si chips arranged thereon as second components 3 is arranged on a support device 10. For the TLPS process used as the joining process in the illustrated embodiment, the support plate 11 is provided as a heating plate. Moreover, in order to adjust the required process temperature, an upper heating device 13 is arranged above the support plate 11 in a swiveling cover 4a of the housing 4, said upper heating device 13 being provided as an IR radiator device comprising a field of parallel halogen tubes 13.

[0043] Analogous to the upper heating device 12, a lower heating device 14 is provided below the support plate 11, said lower heating device 14 also being provided as an IR radiator device comprising a field of parallel halogen tubes, thus allowing two-zone temperature adjustment with optimal temperature distribution during the joining process.

[0044] A pressing device 15 is provided for pressing the chips 3 onto the Cu carrier 2, said pressing device 15 comprising a metallic pressure plate or bonder plate 16, respectively, which is arranged plane-parallel to the support plate 11 and is connected, on its side facing away from the contact pressure side, to a guide rod 17. The guide rod 17 extends out of the housing 4 in a vacuum-sealed manner and is movable by means of a motor 18 in a direction perpendicular to the plane of the support plate 11, i.e. vertically in the present case, and thus towards the components 2, 3 and away from them. A pressure medium duct 25, not shown in detail, is formed inside the guide rod 17. The pressure medium duct 25 is connected to a pressure medium source 26, shown only symbolically, and extends through the pressure plate 16 as far as to the components 2, 3 and, thus, as far as to the side of the pressure plate 16 facing the target surface.

[0045] An expandable membrane 19 is arranged on this contact pressure side of the pressure plate 16, which membrane 19 is made of a gas-tight, elastic sheet material and is designed, in the present case, to be subjected to compressed air as the pressure medium.

[0046] In the embodiment shown, the membrane extends up to the circumference of the pressure plate 16, which is circular here, and is attached to the edge region of the pressure plate 16 by means of a holding and fixing device 20, the latter comprising a clamping ring 21, which extends around the circumference of the membrane 19. The clamping ring 21 is connected to a sealing ring 22 forming the sealing device between the membrane and a flange-like step on the edge of the pressure plate 16, and is also connected to the pressure plate 16 itself.

[0047] As the connecting means of the holding and fixing device 20, screw connections 23 are provided, which are distributed over the circumference of the clamping ring 21 and of the pressure plate 16.

[0048] A control device 24 is provided to adjust at least the fluid pressure of the pressing device 15 according to the predefined process parameters and the topography of the components 2, 3 to be joined, said control device 24 directing compressed air from the pressure medium source 18 into the area between the contact surface of the pressure plate 16 and the membrane 19. This causes the membrane 19 to expand towards the chips 3 forming the target surface and to contact them such that an isostatic contact pressure is applied to all chips 3, which presently have different geometries and different heights.

[0049] In addition to the pressure applied via the pressure medium duct 25, the membrane 19 may be aspirated in the non-contacting state so that it is in planar contact, in this state, with the pressure plate 16 and does not bulge towards the components 2, 3 to be joined, therefore not being able to have a negative effect on them.

[0050] The depicted apparatus 1 is universally applicable and can be used not only for the TLPS process described herein, but also for other soldering and diffusion soldering processes as well as sintering processes. Depending on the joining process selected, only the process parameters, such as temperature, atmosphere and, as the case may be, the material and thickness of the exchangeable membrane will change.