Senate Finance Committee Chairman William V. Roth Jr. plans to unveil a "Roth 401(k) plan early next week as part of a broader retirement package. Under the proposal, workers could contribute after-tax money to a 401(k) plan, but would not have to pay taxes on the investment earnings when they take the money at retirement. Employees still would pay taxes on any matching contributions at retirement. Similar treatment would be extended to Roth 403b plans. The proposal would more than double the amount that could be set aside through individual retirement accounts, to $5,000 a year from $2,000. IRAs would be available to all, irrespective of income. Under current law, IRA eligibility is phased out for higher-income Americans. Contribution limits would be raised on 401(k) and 403b plans to $15,000 from $10,000, and on SIMPLE 401(k)s and IRAs to $10,000 from $6,000. Employees age 50+ could contribute more to IRAs to make up for earlier years. Employers would no longer be hampered in contributing money to their pension plans in good times if their plans had assets exceeding 150% of current liabilities. His proposal would dispose of "full funding limits. Finally, Mr. Roths package would repeal the limit preventing employers and employees from contributing more than 25% of pay to defined contribution plans.