deployProxy.sol

  /**
    * @dev Internal function to deploy a proxy contract for linkdrop master
    * @param _linkdropMaster Address of linkdrop master
    * @return Proxy contract address
    */
    function _deployProxy(address payable _linkdropMaster)
    internal
    returns (address payable)
    {
        require(!isDeployed(_linkdropMaster), "Deployed");
        require(_linkdropMaster != address(0), "Invalid linkdrop master address");

        bytes32 salt = keccak256(abi.encodePacked(_linkdropMaster));
        bytes memory initcode = getInitcode();
        address payable proxy;
 
        // deploying proxy contract via create2 opcode
        assembly {
            proxy := create2(0, add(initcode, 0x20), mload(initcode), salt)
            if iszero(extcodesize(proxy)) { revert(0, 0) }
        }

        deployed[_linkdropMaster] = proxy;
        // Initialize owner address, linkdrop master address and master copy version in proxy contract
        require
        (
            ILinkdropCommon(proxy).initialize
            (
                address(this), // Owner address
                _linkdropMaster, // Linkdrop master address
                masterCopyVersion,
                chainId
            ),
            "Failed to initialize"
        );

        emit Deployed(_linkdropMaster, proxy, salt, now);
        return proxy;
    }