Continuous Process for Employee Awards
In general, please note that such an effort is NOT a one-time affair. It's an all-year-round continuous process that ought to culminate in any such award.
Incorporating Parameters into a Process
Coming to Nathrao's suggestions, I would suggest you incorporate the parameters into a process rather than taking any subjective view. Rate each parameter on a scale of 1-5 and add up the total for all parameters. Whoever gets the maximum rating gets the award. Such a process would be both fair and transparent for all to see. In a way, it could ensure that others who didn't get the award this time would raise their performance levels for next year.
Additional Parameters to Consider
As regards the parameters, in addition to attendance and disciplinary record, you could also add promotions (or excellent appraisal ratings) during the period under consideration, and feedback from team members (if the employee is in a lead/manager position) or from the concerned lead/manager (if the employee is a team member).
Even though taking client feedback is also desirable for client-facing roles, you need to figure out how you would balance this parameter out with others who are not client-facing, since the number of parameters being considered would then change.
Technical and Non-Technical Aspects
You mentioned that 'technical point will be judged by my boss'—what about other aspects of the employee's work, while not strictly technical but related to technical work, like adhering to delivery times, team interaction skills, etc.? Please ensure the division of responsibilities is clearly defined, or being the HR, you are likely to become the scapegoat.
All the best.
Regards,
TS