The Nasdaq rose 79.67 to 3,940.87, and the Standard & Poor's 500 index gained 16.22 to 1,496.07.
The Dow Jones industrial average rose 47.25 to close at 11,055.64.
"The Nasdaq is higher because the semiconductor index continues to roll along," said Larry Wachtel, a market analyst at Prudential Securities.
The Philadelphia semiconductor index rose 37.69 to 1,111.06, led by chipmaker Linear Technology, which gained $5.38 to close at $70. The index has gained nearly 18 percent over the past six days.
At the end of regular trading, Intel closed up $2 at $70.06. Microsoft climbed 56 cents to $71.56.
"It's a good-looking market, but it lacks the pizzazz or the authority of a higher-volume market," Wachtel said.
On the Nasdaq, 1.2 billion shares exchanged hands, the fifth-lowest volume for a full day of trading so far this year. The New York Stock Exchange generated just more than 900 million shares.
The CNET tech index rose 41.61 to close at 3,216.24. Winners thumped losers, with 71 of the 97 stocks in the index rising, 25 falling and one remaining unchanged.
Of the 18 sectors tracked by CNET Investor, semiconductor-equipment companies posted the biggest jumps, leaping about 5 percent. PC-hardware makers were the day's largest losers, slipping almost 2 percent.
Smallworldwide was the biggest percentage gainer on the Nasdaq. Shares of the Cambridge, England-based company jumped $10.81, or about 122 percent, to $19.69 on a volume of 2.3 million shares, more than 135 times the stock's average daily volume of about 17,700 shares.
General Electric, the world's biggest maker of power-plant turbines, agreed to buy the maker of network software for $210 million. GE fell 13 cents to $56.69.
Shares of medical Web site Drkoop.com gained 48 percent today, rising 38 cents to $1.16 after the company said it is exploring financing options.
Among members of the CNET tech index, eBay and BMC Software posted strong gains.
eBay rose $5.56, or nearly 10 percent, to $63.06. The shares have soared more than 25 percent since Monday on investor optimism about the online auction company's international plans. BMC climbed $2.25, or 11 percent, to $22.81.
Brocade Communications Systems rose $15.19 to $211.94 after the company said fiscal third-quarter profit rose more than 12-fold on surging sales of high-speed computer switches for data-storage networks.
Ciena shares rose $15.94, or about 10 percent, to $179.19 after the maker of equipment to boost capacity on fiber-optic networks said fiscal third-quarter profit rose on new product sales and predicted fourth-quarter and 2001 earnings will beat forecasts.
Semiconductor-equipment maker Amtech Systems rose for a second day, gaining $4.63, or 46 percent, to $14.63. The company said it received a $6.4 million order for 11 diffusion-furnace systems from an unidentified telecommunications company. It's the company's largest order.
Investors gave Hewlett-Packard the cold shoulder, sending the stock down $12.75, or almost 11 percent, to $108.13 after the company reported earnings that beat expectations. Revenue was "a little light," according to a research note by PaineWebber analyst Don Young, who cut fourth-quarter earnings estimates from $1.03 to $1.01 a share.
HP reported earnings of 97 cents a share, beating analyst forecasts of 85 cents as surveyed by First Call/Thomson Financial. However, the tech giant received a significant boost of 9 cents a share from nonoperating income items.
Covad Communications fell $1 to $13.63 and set a new 52-week intraday low of $13.31. The provider of high-speed Internet access has traded as high as $66.66 during the same period.
StarMedia Network, an Internet company that targets Latin America, fell $1 to $10.13. The shares traded as low as $9.75, a new 52-week low, compared with a high of $61.