NOVELTY - Measurement and control of strained device involves: measuring stress on at least one of monitor substrate, production substrate (14), and proxy device on production substrate to produce stress data; measuring critical dimension shape on at least one of proxy device on production substrate and production device (12) on production substrate to produce shape data; and inputting stress data and shape data into elastic deformation calculation to determine stress value for production device.    USE - For measurement and control of strained device; and for approximating strain in semiconductor transistor devices (claimed). The devices also include integrated circuit devices such as those formed on monolithic semiconductor substrates e.g. those formed of silicon or germanium, or group III-V compounds like gallium arsenide; memory and logic devices, metal oxide semiconductor (MOS) and bipolar devices; flat panel displays, solar cells, and charge coupled devices.    ADVANTAGE - The methods provide improved method for measuring stress and strain in strained device, where operation of integrated circuit devices, such as semiconductor devices, can be improved when the crystalline channel material is under stress, as resulting lattice strain in channel region changes electronic band structure which changes electron and hole mobilities. The methods provide improvement on methods and systems for obtaining measurements of strain properties in integrated circuits, such as silicon semiconductor devices and other crystalline semiconductor materials. Film stress can be measured using large spot measurements on monitor substrates (non production substrates), on very thin films that can't be measured by standard film stress tools. To achieve the high sensitivity that is needed for these applications, a technique called spectroscopic modulated photoreflectance is used, where optical properties at direct band gap of substrate is modulated, and measurement of those properties is accomplished with a reflected probe beam that has sufficient spectral bandwidth and resolution. Using low-frequency-modulated optical beam such as laser (pump) is effective method for modulating channel optical properties, despite presence of stressed layer that has been deposited over channel, as long as stressor layers are transparent to the pump beam, or at least only very weakly absorbing. Thus, these measurements can be accomplished using large spot system on strained silicon sample buried beneath silicon nitride film. Such a measurement on a monitor substrate provides information on state of residual stress in silicon nitride film deposition process. This can be generalized to more complex film stacks. The film stress information from monitor substrates and geometry information from production substrates can be input to elastic deformation calculation to determine the amount of strain in channel area of the device. This can be accomplished, using finite element methods. The electronic properties of device can also be estimated by adding model for strain dependent band structure. Complex layout-dependent strain and mobility effects can also be simulated. Using this information, decisions about disposition and processing of production substrates can be conditioned on behavior of the most sensitive channel regions of complex unit cell. The methods allow more accurate non-destructive determination of the strain within transistors and ability to monitor within-substrate and substrate-to-substrate variations. By combing strain and shape information, more accurate determinations can be made of the yield at a given device speed, avoiding unnecessary scrapping of substrates or wasteful processing of bad substrates through subsequent processing steps. Knowing the changes in shape geometry before strain is created allows strain-inducing processes to be adjusted to compensate, or vice-versa if strain-inducing processes precede etch process that controls critical shape. Knowing within-channel strain potentially allows other process parameters to be adjusted by small amounts to compensate for small deviations in strain from optimal degree, allowing best compromise between performance and yield.    DETAILED DESCRIPTION - Measurement and control of strained device involves: measuring stress on at least one of monitor substrate, production substrate (14), and proxy device on production substrate to produce stress data; measuring critical dimension shape on at least one of proxy device on production substrate and production device (12) on production substrate to produce shape data; and inputting stress data and shape data into elastic deformation calculation to determine stress value for production device. The method further involves estimating electrical properties of production device based at least in part on stress value for production device; determining difference between stress value for production device and desired stress value for production device; adjusting parameters of up-stream stress inducing processes to reduce difference between stress value and desired stress value of later-processed production substrates; and adjusting parameters of down-stream processes to compensate for difference between stress value and desired stress value of production substrate. An INDEPENDENT CLAIM is included for approximating strain in semiconductor transistor devices, at a point in time when semiconductor transistor devices have overlying layers that are substantially opaque to ultraviolet and visible wavelengths of radiation, involving: forming first test structure and second test structure on common substrate with and concurrently with semiconductor transistor devices; measuring strain in first test structure, where first test structure is fabricated identical to semiconductor transistor devices, except that the first test structure omits overlying layers that are substantially opaque to ultraviolet and visible wavelengths of radiation; measuring critical dimension geometry of second test structure, where second test structure has a geometry that is substantially identical to geometry of first test structure, and second test structure includes overlying layers that are substantially opaque to ultraviolet and visible wavelengths of radiation; and combining strain and geometry measurements to produce approximation of strain in semiconductor transistor devices.    DESCRIPTION OF DRAWING(S) - The figure shows block diagram of system for measurement of strained silicon underneath stressed film, by large spot optical system.    Spectroscopic modulated photoreflectance system (10)    Layer that resides on top of substrate (12)    Substrate (14)    Probe (16)    Pump/laser (18)    Modulator (20)    Spectrograph (22)    Detector array (24)    Controller (26)