Thermal-bonding sheet and thermal-bonding sheet-attached dicing tape

#The present invention relates to thermal bonding sheets usable for the production of semiconductor devices, and to dicing tapes each with such a thermal bonding sheet.

#In some semiconductor device productions, a semiconductor chip is die-bonded to a supporting substrate such as a lead frame or an insulated substrate while establishing and keeping electrical connection with the supporting substrate. Known examples of this technique include the technique of forming a Au—Si eutectic alloy layer between the supporting substrate and the chip to achieve a bonding state; and the technique of using a bonding material such as solder or a resin containing conductive particles.

#Power semiconductor devices, which assume power supply and control, have become widespread remarkably. Many of such power semiconductor devices output large heat due to the passage of large current during operation. The power semiconductor device productions require a technique of die-bonding a semiconductor chip on a supporting substrate while establishing and keeping electrical connection with the supporting substrate, where the technique actually provides a highly reliable bonding state even during a high-temperature operation. In particular, power semiconductor devices that employ SiC or GaN as a semiconductor material and are to be operated at high temperatures significantly demand this. A proposed die bonding technique with electrical connection to meet the requirement employs a material for thermal bonding (thermal-bonding material) including a composition containing, for example, sinterable particles and a solvent.

#FIG. 1 is a schematic partial cross-sectional view of a thermal bonding sheet according to an embodiment of the present invention;

#FIG. 2 illustrates a part of steps in a semiconductor device production method using the thermal bonding sheet illustrated in FIG. 1;

#FIG. 3 illustrates a part of steps in the semiconductor device production method using the thermal bonding sheet illustrated in FIG. 1;

#FIG. 1 is a schematic partial cross-sectional view of a thermal bonding sheet 10 according to an embodiment of the present invention. The thermal bonding sheet 10 is used for sinter bonding between bonding targets and includes a pressure-sensitive adhesive layer 11. The pressure-sensitive adhesive layer 11 includes sinterable particles containing a conductive metal (conductive-metal-containing sinterable particles), a thermally decomposable polymer binder, and a low-boiling binder. The thermal bonding sheet 10 as above is usable, typically in a semiconductor device production process, for sinter bonding of a semiconductor chip to a supporting substrate while establishing and keeping electrical connection with the supporting substrate.

#The sinterable particles contained in the thermal bonding sheet 10 or in the pressure-sensitive adhesive layer 11 of the sheet 10 are particles that contain a conductive metal element and are sinterable. Non-limiting examples of the conductive metal element include gold, silver, copper, palladium, tin, and nickel. Examples of the material to constitute such sinterable particles include gold, silver, copper, palladium, tin, and nickel; and alloys of two or more metals selected from the group consisting of these metals. Examples of the material to constitute the sinterable particles also include metal oxides such as silver oxide, copper oxide, palladium oxide, and tin oxide. The sinterable particles may be particles having a core-shell structure. For example, the sinterable particles may be core-shell structure particles, which include a core mainly containing copper, and a shell mainly containing, for example, gold or silver and covering the core. In the embodiment, the sinterable particles preferably include at least one selected from the group consisting of silver particles, copper particles, silver oxide particles, and copper oxide particles.

#The sinterable particles have an average particle size of preferably 1000 nm or less, more preferably 800 nm or less, and still more preferably 500 nm or less, from the viewpoint of surely providing satisfactory sinterability typically by allowing the sinterable particles to actually have a low sintering temperature. The sinterable particles have an average particle size of preferably 10 nm or more, more preferably 50 nm or more, and still more preferably 100 nm or more, from the viewpoint of allowing the sinterable particles to be surely satisfactorily dispersible in the pressure-sensitive adhesive layer 11 or in a composition to form the layer 11.