A rise in technology spending by a corporate side also helped push up IT services provider Fujitsu's <6702.T> first-quarter profits.
Toshiba, its bigger rival Samsung Electronics <005930.KS>, and other NAND-type flash memory makers are benefiting from booming demand for chips used in devices such as Apple Inc's iPhone and iPad, prompting Elpida to enter the market through a tie-up with Spansion
The companies are also gaining from a tight supply and strong prices since last year's severe sector downturn had forced many NAND chipmakers to shrink production or go under.
Elpida, a maker of dynamic random access memory (DRAM) chips, was buoyed by strong PC shipments and emerging segments of new, smaller computers, while improving analog chip demand used for vehicles and electronics helped Renesas.
Renesas, the world's fifth-largest chipmaker created in April through a merger of Renesas Technology and NEC Electronics, still made a quarterly loss on merger costs and other expenses.
Toshiba, the world's No. 3 chipmaker overall, posted a fourth consecutive quarterly operating profit at 29.5 billion yen ($337.2 million), beating a consensus for a 24.2 billion yen profit in a poll of three analysts by Thomson Reuters I/B/E/S.
To boost growth, it has been focusing on emerging areas such as smart grids and lithium-ion batteries besides its traditional chip and nuclear power businesses.
Toshiba retained its full-year outlook for a doubling of operating profit to 250 billion yen, below consensus of 256 billion yen.
The NAND flash memory market is thriving, but some analysts warn it is heading to another supply glut as companies ramp up investments. Toshiba recently started constructing its latest chip plant.
Research firm iSuppli said this month an oversupply of chips used for removable memory cards and USB drives helped global revenue from NAND shipment to fall 6.5 percent in April-June, but said the sector was set to return to growth in the next five quarters.
Renesas expects a 7 billion yen operating profit for the year to March, bigger than a consensus of 4.3 billion yen from a poll of eight analysts. This is the first time the company issued a profit outlook.
Elpida, which trails Samsung and Hynix Semiconductor <000660.KS> in the DRAM market, did not provide full-year outlook, but analysts on average see a 124 billion yen profit, marking a jump of almost five times from a year ago.
Elpida reported April-June operating profit of 44.4 billion yen, beating a consensus for 40.2 billion yen.
Fujitsu kept its operating profit forecast at 185 billion yen for the year to March, in line with market consensus. That would be twice as much profit from a year earlier. Its quarterly earnings returned to an operating profit of 10 billion yen.
(Editing by Anshuman Daga and Mathew Veedon)