PATTERN FORMING METHOD AND METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE

According to one embodiment, a core material is ejected onto an object using an inkjet method to form a core pattern on the object, a mask pattern is formed on the object so as to embed the core pattern, and the core pattern which is embedded in the mask pattern is removed.

DETAILED DESCRIPTION

According to an embodiment, a core material is ejected onto an object using an inkjet method to form a core pattern on the object, a mask pattern is formed on the object so as to embed the core pattern, and the core pattern which is embedded in the mask pattern is removed.

Hereinafter, with reference to accompanying drawings, a pattern forming method and a method of manufacturing a semiconductor device according to an embodiment will be described in detail. However, the present invention is not limited by the embodiments.

FIG. 1Ais a perspective view illustrating an example of a schematic configuration of a semiconductor chip which is used for a method of manufacturing a semiconductor device according to a first embodiment, andFIG. 1Bis a perspective view illustrating a schematic configuration of a semiconductor wafer from which the semiconductor chip ofFIG. 1Ais cut out.

Referring toFIG. 1A, an integrated circuit2is formed on a semiconductor chip P, and pad electrodes3are formed on the periphery of the semiconductor chip P. Further, the integrated circuit2may be a storage device such as an NAND flash memory, a DRAM, or an SRAM or a logical circuit such as an ASIC, or an arithmetic device such as a processor.

Here, as illustrated inFIG. 1B, the integrated circuit2and the pad electrodes3are formed on a semiconductor wafer W and the semiconductor wafer W is cut along a scribe line B to cut out the semiconductor chip P.

FIGS. 2A to 2EandFIGS. 3A to 3Dare cross-sectional views illustrating the method of manufacturing a semiconductor device according to the first embodiment. Further,FIGS. 2A to 2EandFIGS. 3A to 3Dillustrate a portion cut along A-A line ofFIG. 1A.

Referring toFIG. 2A, a core material5is ejected on a rear surface of a semiconductor substrate1from a nozzle4using an inkjet method to form a core pattern6on the rear surface of the semiconductor substrate1, as illustrated inFIG. 2B. In this case, the core pattern6is desirably disposed at an inner side of the pad electrode3. As a material of the core material5, an organic film such as a resist or polyimide may be used. A particle size of the core material may be set to be 50 nm or smaller. A thickness of the core pattern6is desirably 10 μm or larger.

Next, as illustrated inFIG. 2C, a mask pattern7is formed on the rear surface of the semiconductor substrate1using a method such as a coating method so as to embed the core pattern6. Further, a material for the mask pattern7may be selected so as to have an etching rate which is lower than that of the core pattern6, for example, an inorganic film such as SOG (spin on glass) may be used. In this case, the entire core pattern6may be embedded in the mask pattern7or the core pattern6may be embedded in the mask pattern7so as to expose an upper portion of the core pattern6.

Next, as illustrated inFIG. 2D, when the entire core pattern6is embedded in the mask pattern7, the mask pattern7is thinned using a method such as RIE or CMP so that the upper portion of the core pattern6is exposed.

Next, as illustrated inFIG. 2E, the core pattern6is removed to form an opening8, on which the core pattern6is transferred, on the mask pattern7. When the core pattern6is the organic film and the mask pattern7is SOG, an ashing process such as oxygen plasma may be performed to selectively remove the core pattern6.

Next, as illustrated inFIG. 3A, the semiconductor substrate1is etched from the rear surface using the mask pattern7on which the opening8is formed as a mask to form a through hole9in the semiconductor substrate1. In this case, the through hole9may be disposed at an inner side of the pad electrode3. Further, the rear surface of the pad electrode3may be exposed through the through hole9.

Next, as illustrated inFIG. 3B, the mask pattern7is removed using a method such as a wet etching process. Further, when the mask pattern7is SOG, hydrofluoric acid may be used as a chemical of the wet etching process. Next, an insulating film10is formed on the rear surface of the semiconductor substrate1using a CVD method so as to cover a side surface of the through hole9. Further, for example, a silicon dioxide film may be used as the insulating film10. Further, the insulating film10which is attached onto the rear surface of the pad electrode3may be selectively removed by an RIE method.

Next, as illustrated inFIG. 3C, an embedded electrode12which is connected to the rear surface of the pad electrode3with a seed layer11interposed therebetween is embedded in the through hole9. As a method of embedding the embedded electrode12in the through hole9, for example, electrolytic plating may be used. For example, TiN may be used for the seed layer11and Cu may be used for the embedded electrode12.

The above described processes ofFIGS. 2A to 2EandFIGS. 3A to 3Cmay be performed in a state of the semiconductor wafer W ofFIG. 1B. Therefore, the semiconductor wafer W in which the embedded electrode12is embedded is cut along the scribe line B to cut out the semiconductor chip P.

Next, as illustrated inFIG. 3D, semiconductor chips P1to P3in which embedded electrodes12are embedded are laminated with protruding electrodes13therebetween and pad electrodes3and the embedded electrodes12of upper and lower semiconductor chips P1to P3, respectively, are connected. Further, the protruding electrode13may be, for example, a solder ball or a metal bump which is formed of Au or Ni. Further, the semiconductor chips P1to P3are inspected before laminating the semiconductor chips P1to P3and only non-defective semiconductor chips P1to P3may be selected.

Here, the core pattern6is formed on the rear surface of the semiconductor substrate1using the inkjet method to increase a thickness of the core pattern6, which is more effective to increase a thickness of the mask pattern7than a method that forms the mask pattern7using a photolithography method. Therefore, even when a thickness of the semiconductor substrate1is large, the through hole9may be formed in the semiconductor substrate1using the mask pattern7as a mask.

Further, in the above-described embodiment, even though it has been described that the core pattern6for forming the mask pattern7is formed using the inkjet method when the through hole9is formed in the semiconductor substrate1, when a pattern other than the mask pattern is formed on the object, the core pattern for forming the mask pattern may be formed using the inkjet method. For example, when the pad electrode3is formed, the core pattern for forming the mask pattern may be formed using the inkjet method. In this case, SOG may be desirably used for the core pattern, and polyimide may be desirably used for the mask.

FIGS. 4A to 4Care cross-sectional views illustrating a method of manufacturing a semiconductor device according to a second embodiment. Further,FIGS. 4A to 4Cillustrate a portion cut along A-A line ofFIG. 1A.

Referring toFIG. 4A, a mask material14is ejected on a rear surface of a semiconductor substrate1from a nozzle4using an inkjet method to form a mask pattern15having an opening16on the rear surface of the semiconductor substrate1, as illustrated inFIG. 4B. In this case, the opening16is desirably disposed at an inner side of a pad electrode3. As a material for the mask material14, for example, an organic film such as a resist or polyimide or an inorganic film such as SOG may be used. A particle size of the mask material14may be set to be 50 nm or smaller. A thickness of the mask pattern15is desirably 10 μm or larger.

Next, as illustrated inFIG. 4C, the semiconductor substrate1is etched from the rear surface using the mask pattern15having the opening16as a mask to form a through hole9in the semiconductor substrate1. In this case, the through hole9may he disposed at the inner side of the pad electrode3. Further, the rear surface of the pad electrode3may be exposed through the through hole9.

Next, similarly to the processes ofFIGS. 3B to 3D, an embedded electrode12which is connected to the rear surface of the pad electrode3with a seed layer11interposed therebetween is embedded in the through hole9. Therefore, the semiconductor chips P1to P3in which the embedded electrodes12are embedded are laminated with protruding electrodes13therebetween.

Here, the mask pattern15is formed on the rear surface of the semiconductor substrate1using the inkjet method to increase the thickness of the mask pattern15as compared with a method that forms the mask pattern15using the photolithography method. Therefore, even when a thickness of the semiconductor substrate1is large, the through hole9may be formed in the semiconductor substrate1using the mask pattern15as a mask.

Further, in the above-described embodiments, even though a method that forms the mask pattern15for forming the through hole9in the semiconductor substrate1using the inkjet method has been described, a mask pattern for forming other patterns on the object may be formed using the inkjet method.