Assembly of multi-chip modules with proximity connectors using reflowable features
A multi-chip module (MCM) that includes at least two substrates, having facing surfaces, which are mechanically coupled by a set of coupling elements having a reflow characteristic, is described. One of the two substrates includes another set of coupling elements having another reflow characteristic, which is different than the reflow characteristic. These different reflow characteristics of the sets of coupling elements allow different temperature profiles to be used when bonding the two substrates to each other than when bonding the one of the two substrates to a carrier. For example, the temperature profiles may have different peak temperatures and/or different durations from one another. These reflow characteristics may facilitate low-cost, high-yield assembly and alignment of the substrates in the MCM, and may allow temperature-sensitive components to be included in the MCM.
1. A multi-chip module (MCM), comprising:
a first substrate having a first surface and a second surface on an opposite side of the first substrate from the first surface, wherein a set of first coupling elements are disposed on the first surface, wherein each first coupling element comprises a layer with a first reflow characteristic, and wherein the set of first coupling elements are configured to mechanically couple the first substrate to another component; and
a second substrate having a third surface that is mechanically coupled to one of the first surface and the second surface by a set of second coupling elements, wherein each second coupling element comprises a layer with a second reflow characteristic, and wherein the first reflow characteristic is different than the second reflow characteristic,
wherein each coupling element in the set of first coupling elements comprises a positive feature and a negative feature, wherein the negative feature of the coupling element in the set of first coupling elements defines an opening on the first surface of the first substrate and wherein the positive feature of the coupling element in the set of first coupling elements is coupled to the negative feature inside the opening and protrudes from the first surface,
wherein a set of first proximity connectors are disposed on one of the first surface and the second surface,
wherein a set of second proximity connectors are disposed on the third surface, and
wherein the set of second coupling elements align the first proximity connectors and the second proximity connectors, and assemble the MCM, thereby facilitating proximity communication between the first substrate and the second substrate.
2. The MCM of claim 1 , wherein the first reflow characteristic is associated with a first temperature profile with a first peak temperature and a first duration that is used when reflowing at least a portion of the set of first coupling elements;
wherein the second reflow characteristic is associated with a second temperature profile with a second peak temperature and a second duration that is used when reflowing at least a portion of the set of second coupling elements; and
wherein at least one of the first peak temperature is different from the second peak temperature and the first duration is different from the second duration.
3. The MCM of claim 1 , wherein the set of first coupling elements includes a set of first positive features that protrudes above the first surface;
wherein the set of second coupling elements includes a set of second positive features that protrudes above the third surface, and one of the first surface and the second surface; and
wherein a given positive feature in one of the set of first positive features and the set of second positive features includes a spherically shaped coupling component.
4. The MCM of claim 3 , wherein the first reflow characteristic is associated with the set of first positive features, and the second reflow characteristic is associated with the set of second positive features.
5. The MCM of claim 3 , wherein the set of second coupling elements includes a set of first negative features that are recessed below one of the first surface and the second surface, and includes a set of second negative features that are recessed below the third surface; and
wherein a given second positive feature in the set of second positive features is, respectively, mechanically coupled to a pair of negative features that includes one of the first negative features and one of the second negative features.
6. The MCM of claim 5 , wherein the second reflow characteristic is associated with the set of first negative features and the set of second negative features.
7. The MCM of claim 5 , wherein the second reflow characteristic is associated with the set of second positive features, the set of first negative features and the set of second negative features.
8. The MCM of claim 5 , wherein a given negative feature in the set of first negative features and the set of second negative features includes an etch pit.
9. The MCM of claim 3 , wherein the set of first coupling elements includes a set of first negative features that are recessed below the first surface and that are mechanically coupled to corresponding first positive features.
10. The MCM of claim 9 , wherein the first reflow characteristic is associated with the set of first negative features.
11. The MCM of claim 9 , wherein the first reflow characteristic is associated with the set of first positive features and the set of first negative features.
12. The MCM of claim 1 , wherein one of the set of first coupling elements and the set of second coupling elements is configured to provide electrical coupling.
13. A method for assembling multi-chip module (MCM), comprising:
mechanically coupling a first surface of a first substrate in the MCM to another component by reflowing a set of first coupling elements disposed on the first surface based on a first reflow characteristic of the first coupling elements, wherein each first coupling element comprises a layer with the first reflow characteristic; and
mechanically coupling one of the first surface and a second surface of the first substrate to a third surface of a second substrate in the MCM by reflowing a set of second coupling elements in the MCM based on a second reflow characteristic of the set of second coupling elements, wherein each second coupling element comprises a layer with the second reflow characteristic, and wherein the first reflow characteristic is different than the second reflow characteristic,
wherein each coupling element in the set of first coupling elements comprises a positive feature and a negative feature, wherein the negative feature of the coupling element in the set of first coupling elements defines an opening on the first surface of the first substrate and wherein the positive feature of the coupling element in the set of first coupling elements is coupled to the negative feature inside the opening and protrudes from the first surface,
wherein a set of first proximity connectors are disposed on one of the first surface and the second surface,
wherein a set of second proximity connectors are disposed on the third surface, and
wherein the set of second coupling elements align the first proximity connectors and the second proximity connectors, and assemble the MCM, thereby facilitating proximity communication between the first substrate and the second substrate.