Thermal Warpage Research Articles

Correction of thermal airflow distortion in warpage measurements of microelectronic packaging structures via deep learning-based digital image correlation

The projected speckle-based three-dimensional digital image correlation method (3D-DIC) is being increasingly used in the reliability measurement of microelectronic packaging structures because of its noninvasive nature, high precision, and low cost. However, during the measurement of the thermal reliability of packaging structures, the thermal airflow generated by heating introduces distortions in the images captured by the DIC measurement system, impacting the accuracy and reliability of noncontact measurements. To address this challenge, a thermal airflow distortion correction model based on the transformer attention mechanism is proposed specifically for the measurement of thermal warpage in microelectronic packaging structures. This model avoids the oversmoothing issue associated with convolutional neural networks and the lack of physical constraints in generative adversarial networks, ensuring the precision of grayscale gradient changes in speckle patterns and minimizing adverse effects on DIC calculation accuracy. By inputting the distorted images captured by the DIC measurement system into the network, corrected images are obtained for 3D-DIC calculations, thus allowing the thermal warpage measurement results of the sample to be acquired. Through experiments measuring topography with customized step block specimens, the effectiveness of the proposed method in improving warpage measurement accuracy is confirmed; this is particularly true when captured images are affected by thermal airflow at 140 °C and 160 °C, temperatures commonly encountered in thermal reliability testing of packaging structures. The method successfully reduces the standard deviation from 9.829 to 5.943 µm and from 12.318 to 6.418 µm, respectively. The results demonstrate the substantial practical value of this method for measuring thermal warpage in microelectronic packaging structures.

A Workflow for the Compensation of Substrate Defects When Overprinting in Extrusion-Based Processes

Fused granular fabrication (FGF) is used in industrial applications to manufacture complex parts in a short time frame and with reduced costs. Recently, the overprinting of continuous fibre-reinforced laminates has been discussed to produce high-performance, functional structures. A hybrid process combining FGF with Automated Fibre Placement (AFP) was developed to implement this approach, where an additively manufactured structure is bonded in situ onto a thermoplastic laminate. However, this combination places great demands on process control, especially in the first printing layer. When 3D printing onto a laminate, the height of the first printed layer is decisive to the shear strength of the bonding. Manufacturing-induced surface defects of a laminate, like thermal warpage, gaps, and tape overlaps, can result in deviations from the ideal geometry and thus impair the bonding strength when left uncompensated. This study, therefore, proposes a novel process flow that uses a 3D scan of a laminate to adjust the geometry of the additively manufactured structure to achieve a constant layer height in the 3D print and, thus, constant mechanical properties. For the above-listed surface defects, only thermal warpage was found to have a significant effect on the bonding strength.

Local thermal warpage deformation of polypropylene injection molded flat part and neural network prediction model

Local thermal warpage deformation of polypropylene injection molded flat part and neural network prediction model

The metamaterial with high thermal-mechanical stability and the practical application as the microwave antenna: Mechanical designs, theoretical predictions, and experimental demonstrations

To address the demand of maintaining the structural configuration upon extreme temperature changes, metamaterials with high thermal-mechanical stability have attracted wide attention recently. However, there are still some challenges for previous studies regarding mechanical design and practical application exploration. This manuscript proposes the design strategy for the lattice sandwich metamaterial with excellent zero thermal-induced warping, along with the metamaterial-based antenna with a high stability of electromagnetic signal transmission. Through the design strategy of discrete lattice units of the metamaterial, the ultra-low thermal warping of the metamaterial is realized upon the non-uniform temperature field. Here, the theoretical model is established to predict both heat transfer and thermal-induced deformation behavior upon complex mechanical-thermal loading conditions. The combination of theoretical predictions, finite element analysis, and experiments verifies the thermal dimensional stability of the metamaterial proposed here. Compared with the heterogeneous bilayer plate, experimental thermal warping of the metamaterial specimen is reduced by 99.7%. Additionally, compared with the bilayer-based specimen, gain attenuation, the main lobe's offset angle, and the voltage standing wave ratio offset of the metamaterial-based antenna specimen are experimentally reduced by 99.5%, 99.9% and 74.2%, revealing the huge application potential of this metamaterial in the field of spacecraft communication.

Addressing Challenges in Dual Sided SiP Thermal Budget

System-in-Package (SiP) has been adopted as the mainstream advanced packaging technology in many consumer applications including 5G smartphones, tablets, wireless earbuds, smart wearables, etc. Heterogeneous integration, smaller form factor, better electrical performance, lower cost of assembly and faster time to market are the key differentiators of SiP as compared to conventional packaging techniques. In applications such as 5G mobile RF Front-End (RFFE) and Antenna-in-package (AiP) modules, dual sided SiP is the popular approach which brings even higher level of integration and smaller form factor. However thermal warpage control is a significant challenge during two times of solder reflow processes for the front and back sides of the package, especially if one side is with underfill and mold materials which have significant CTE mismatch to the substrate and dies, causing delamination failures and yield losses. This study examines the novel solution of reducing thermal budget with the use of a low temperature solder paste material based on SnBiAg alloy in ultra-fine pitch Type 6 solder powders. It allows a minimal peak reflow temperature of only 170 °C that effectively reduces warpage of dual sided SiP substrates. Solder alloy and paste properties and solder joint microstructures are examined in detail for tests including fine-pitch printing and component soldering, thermal aging test on different substrate finishes, thermal cycling test and mechanical drop test for reliability performance.

Residual Stress Testing and Simulation Analysis of Crystal Structures of Electronic Device Materials

In this paper, we analyze the residual stress of different components of the crystal structures of electronic device materials following exposure to elevated temperatures using a combination of experimental tests and finite element simulations. X-ray diffraction (XRD) and LXRD micro-area residual stress analyzer were employed to determine the residual strain and stress of the CBGA sample encapsulation cover and solder joints. Subsequently, the experimental data were utilized to verify the accuracy of the simulation. The discrepancy between experimental measurements and simulation outcomes of the residual stress following reflow soldering of CBGA-assembled micro-solder joints is below 14%. The analysis also included thermal warping deformation of the CBGA encapsulation cover and how the residual stress was influenced by the diameter, spacing, and height of the solder joints. The study reveals that the residual stress following reflow soldering of BGA solder joints is non-uniformly distributed within the array. Within a single solder joint, residual stress gradually increases in distribution from its middle to the point where it make contact with the PCB and chip, with the highest level of residual stress observed where the solder joint contacts the chip. The variation in material parameters, such as the coefficient of thermal expansion, is the primary cause of thermal warping deformation on the surface of CBGA encapsulation covers. Three primary factors significantly impact the residual stress on BGA solder joints: solder joint diameter, spacing, and height. The maximum value is inversely proportional to the height of the solder joints and the residual stress. Conversely, the diameter and spacing of the joints are positively proportional to the highest value. When the diameter of the solder joint is increased from 0.55 mm to 0.75 mm, the maximum residual stress in the BGA solder joint increases from 37.243 MPa to 36.835 MPa. Conversely, increasing the height of the solder joint from 0.36 mm to 0.44 mm reduces the stress from 39.776 MPa to 36.835 MPa.

Enhancing predictability of thermal warpage by applying temperature-dependent Poisson's ratio of epoxy molding compound

The warpage behavior of electronic packages has become complicated in recent years owing to the miniaturization and heterogeneous integration technologies. Therefore, stress analyses through warpage simulations have become increasingly challenging. Understanding the thermo-mechanical behavior of epoxy-based packaging materials enhances the predictability of warpage simulation and helps in designing mechanically reliable electronic packages. However, the necessity and importance of an accurate database of thermo-elastic properties, especially the temperature dependency of Poisson's ratio, still has been overlooked for warpage prediction. In this study, the warpage prediction accuracy of a molded wafer was dramatically improved by measuring and applying the temperature dependency of elastic modulus and Poisson's ratio. If the temperature dependency of Poisson's ratio and elastic modulus is not considered, the warpage prediction error increases by 4.3 and 8.1 times for the 25 °C and 250 °C warpage, respectively. Surprisingly, even without considering only the temperature dependency of Poisson's ratio, the prediction error increased by 3.3 and 4.4 times for the 25 °C and 250 °C warpage, respectively. These results indicate that Poisson's ratio significantly affects the coefficient of thermal expansion-induced warpage behavior in the form of the biaxial modulus.

Hot tear cracks on the suppression of Sn–Bi alloy for low-temperature assembly

PurposeIn the electronic assembly industry, low-temperature soldering holds great potential to be used in surface mounting technology. Tin–bismuth (Sn–Bi) eutectic alloys are lead-free solders applied in consumer electronics because of their low melting point, high strength and low cost. This paper aims to investigate how to address the problem of hot tear crack formation during Sn–Bi low-temperature solder (LTS) in the mass production of consumer electronics.Design/methodology/approachThis paper explored the development of hot tear cracks during Sn–Bi soldering in the fabrication of flip chip ball grid arrays. Experiments were designed to simulate various conditions encountered in Sn–Bi soldering. Quantitative analysis was conducted on the number of hot tear cracks observed in different alloy compositions and solder volumes to explore the primary cause of hot tear cracks and possible methods to suppress crack formation.FindingsHot tear cracks existed in Sn–Bi solders with different bismuth (Bi) contents, but increasing the solder volume reduced the number of hot tear cracks. Experiments were designed to test the degree of chip transient thermal warpage with temperature change, and, according to the results, glue was dispensed in specific areas to reduce chip warpage deformation. Finally, the results of combined process experiments pointed to an effective method of low-temperature soldering to suppress hot tear cracks.Research limitations/implicationsThe study focuses on Sn–Bi solders only without other solder pastes such as SAC305 or Sn–Zn series.Practical implicationsWith the growing popularity of smart electronics, especially in intelligent terminals, new energy vehicles electronics, solar photovoltaic and other field, there will be more and more demand for low- temperature, energy-saving, lead-free solders. Therefore, this study will help the industry to roll out LTS (Sn–Bi) solutions rapidly.Social implicationsIn the long term, lean and green manufacturing is expected to be essential for maintaining an advanced manufacturing industry across the world. Developing new LTSs and soldering processes is the most effective, direct solution for energy conservation and emission mitigation. With the growing popularity of smart electronics, especially in intelligent terminals, new energy vehicles and solar photovoltaics, there would be an increased demand for low-temperature, energy-saving, lead-free techniques.Originality/valueAlthough there are many methods that can be used to suppress hot tear cracks, there is little research on how to control the hot tear cracks caused by the low-temperature soldering of Sn–Bi in laptop applications. The authors studied the hot tear cracks that developed during the world’s first mass production of 50 million personal laptops based on low-temperature Sn–Bi alloy solder pastes. By controlling the Bi content, redesigning the solder paste printing process (e.g. through a printer’s stencil) and adding dispensing processes, the authors obtained reliable and stable experimental data and conclusions.

Measurements and Modelling of Thermally Induced Warpages of DIMM Socket Server PCB Assembly after Solder Reflow Processes.

The thermal warpage of a server-computer-used DIMM socket-PCB assembly after the solder reflow process is studied experimentally, theoretically, and numerically, especially along the socket lines and over the entire assembly. Strain gauge and shadow moiré are used for determining the coefficients of thermal expansion of the PCB and DIMM sockets and for measuring the thermal warpages of the socket-PCB assembly, respectively, while a newly proposed theory and a finite element method (FEM) simulation are used to calculate the thermal warpage of the socket-PCB assembly in order to understand its thermo-mechanical behavior and then further identify some important parameters. The results show that the theoretical solution validated by the FEM simulation provides the mechanics with the critical parameters. In addition, the cylindrical-like thermal deformation and warpage, measured by the moiré experiment, are also consistent with the theory and FEM simulation. Moreover, the results of the thermal warpage of the socket-PCB assembly from the strain gauge suggest a warpage dependence on the cooling rate during the solder reflow process, due to the nature of the creep behavior in the solder material. Finally, the thermal warpages of the socket-PCB assemblies after the solder reflow processes are provided through a validated FEM simulation for future designs and verification.

A thermo-elastic-hydrodynamic model for air foil thrust bearings considering thermal seizure and failure analyses

This study aims to investigate the thermo-elastic performance of an air-lubricated thrust bearing under the thermal failure effect. A thermo-elastic-hydrodynamic model was established using temperature-dependent alloy material properties. The thermo-elastic deformation characteristics were analyzed based on the fluid-thermal-structure interaction approach. The mechanisms of bearing thermal seizures and failure behavior were studied. The results show that the rotor thermal warping deformation at low rotating speed plays a leading role in the increase of the film thickness. The rotor-foil thermal seizure occurs in a high rotating speed. The additional forced cooling conditions effectively reduce the risk of thermal failure.

Hindered thermal warping triggers tensile cracking in the cores of compressed columns of a fire-loaded tunnel segment structure: Efficiency and accuracy of beam theory prediction, compared to FEM

The nonlinear Finite Element Method (FEM) is the current gold standard for the thermo-mechanical analysis of reinforced concrete structures. As an alternative, this paper is devoted to a model reduction strategy which reduces the CPU time by a factor of 500. This strategy combines Fourier series-based solutions for the thermal conduction problem, and thermo-elastic Timoshenko beam theory. Temperature histories known to be relevant for fire accidents enter series solutions quantifying the conduction of heat into a closed cell frame consisting of slabs, walls, and columns. Corresponding temperature profiles are translated into thermal eigenstrains. The latter are represented as the sum of three portions: (i) their cross-sectional averages (called thermal eigenstretches); (ii) their cross-sectional moments (called thermal eigencurvatures); and (iii) the remaining eigenstrain distributions (called eigenwarping). The latter portion is hindered at the cross-sectional scale, giving rise to non-linearly distributed self-equilibrated thermal stresses. The eigenstretches and eigencurvatures, in turn, are constrained at the scale of the frame structure. Together with external mechanical loads, they enter the exact solutions of thermo-elastic Timoshenko beam theory with equivalent cross-sections accounting for the different material properties of concrete and steel. Axial normal stresses, quantified from beam-theory-related normal forces and bending moments, are superimposed with the hindered-warping-induced stresses. These stresses agree well with corresponding results obtained by the nonlinear FEM. As regards the load carrying behavior of the columns, excessive thermal tensile strains at the periphery of the columns trigger, in the core of the columns, large tensile stresses which even exceed the strength of concrete. Respective cracking events are considered through reduced effective columnar cross-sections. Right after initiation of cracking, around 12min after the start of the heating process, the cracks propagate for some 30sec quite rapidly, and very much slower thereafter. If the initial cross-sections of the columns are increased, more pronounced hindered thermal warping, together with less quickly evolving compressive forces, results in earlier cracking. Overall, it is concluded that tensile cracking is the key material non-linearity, at least during the first 30min of the fire test, with maximum temperatures up to 300°C.

Anomalous upconversion behavior and high-temperature spectral properties of Yb/Ho-SiAlON ceramics

Traditionally, NaYF4 and glass-based materials are considered the most efficient upconversion materials. However, those materials may show signs of thermal warping or risks of fracture during long-term service life in extreme environments. In contrast, SiAlON ceramics preserve their spectral and physical integrity during continuous use due to their ultra-low thermal expansion coefficient (∼3.0 × 10−6/K) even at extreme temperatures. Here, we investigate the upconversion photoluminescence properties of Ho and Yb co-doped SiAlON (Ho/Yb-SiAlON) ceramics, prepared by hot-press method, at room temperature and at high temperature (298–1023 K). At room temperature, Ho/Yb-SiAlON ceramics show intense red upconversion emission under 980 nm excitation. At the high-temperature range, the spectral shift is absent in Ho/Yb-SiAlON indicating that the SiAlON ceramics have high-temperature spectral stability, which may be attributed to the low thermal expansion coefficient of SiAlON ceramics. Ho and Yb concentration-dependent spectra show an anomalous upconversion emission behavior. It is found that a higher sensitizer and low activator concentration combination is not always an ideal choice for sensitized luminescence in SiAlON ceramics which is in stark contrast to the common understanding of sensitized luminescence. The mechanism involving the dominant cross-relaxation process has been proposed to explain the observed anomalous upconversion behavior.

Improving the extension–twist coupling performance of practically warpage-free laminates via layup hybridization

This article investigates whether the extension–twist and bend–twist coupling performance of practically warpage-free laminates can be improved by layup hybridization (carbon/epoxy–glass/epoxy hybrids) compared to non-hybrid (mono) laminates. We performed numerical layup search by simulating the thermal warpage, and the bend–twist and extension–twist behaviour of 4096 4-ply layup permutations. The upper limit of allowable manufacturing-induced warpage was based on the ISO2768 standard. The optimal hybrid and mono layups were selected to have the most significant coupling performance within the allowable warpage range. A mono layup achieved the maximum bend–twist performance (which does not require layup asymmetry), but layup hybridization increased the extension–twist performance by more than 30% in the practically warpage-free range. The numerical results were validated through 3D scanning and 3D digital image correlation–aided mechanical tests. We concluded that layup hybridization can significantly improve the extension–twist performance of realistically usable composite laminates with negligible thermal warpage.

Thermally induced mechanical work and warpage compensation of asymmetric laminates

The thermal warpage of asymmetric laminates can be converted into mechanical work. However, thermal warpage is usually unwanted, and can be mitigated with compensatory tool designs. This paper investigates both concepts, focusing on monostability, bistability and the transitional behaviour between the two. Numerical and experimental results showed that the maximum achievable mechanical work goes through a local maximum and then a local minimum as the laminate transitions from bistability to monostability with a decreasing edge length to thickness ratio. The local maximum was correlated with the appearance of the second principal curvature, while the local minimum took place just before reaching the bifurcation point. We successfully manufactured laminates from the monostable region flat using tools with two significant principal curvatures. Laminates from the bistable region were successfully transformed to monostable laminates with similar tools, implying that successful warpage compensation of bistable laminates requires tools that include both principal curvatures.

Multi-Parameter Layup Optimization and the Effect of Layup Homogenization on the Bending Compliance Matrix of Coupled Composites

The behaviour of fibre-reinforced composites greatly depends on their layup structures. Through a full-field layup optimization study based on multiple parameters, this paper investigates how different properties change with the layup. The aim was to maximize the extension-twist coupling performance while ensuring adequate bending stiffness and low thermal warpage to make the laminate suitable for shape-adaptive helicopter rotor blade application. The Classical Laminate Theory-based calculations revealed that satisfying the bending compliance and thermal warpage criteria significantly limited the achievable extension-twist performance. The warpage limit affected the desired coupling behaviour more because both properties are driven by terms in the extensional-bending compliance matrix, unlike bending compliance. Symmetric laminates do not have an intrinsic extension-twist capability, but some asymmetric laminates demonstrated significant coupling performance while being practically warpage-free (based on the ISO2768 standard). The results prove that the advantages of asymmetric laminates can outweigh their sometimes negligible disadvantages. The paper also investigates if there is a universal tendency in how layup homogenization affects the terms of the bending compliance matrix of composites. Through analytical calculations, we showed that depending on the layup of the sub-laminate, homogenization can increase or reduce the value of any term in the bending compliance matrix; therefore, there is no universal tendency. Based on these results, layup homogenization cannot only be exploited for its most general purpose – warpage mitigation – but also for improving other characteristics of the laminate (e.g. reducing the bending compliance for increased bending stiffness or increasing the bend-twist compliance for improved coupling performance).

Stress behavior of concrete pavement

Warping stresses and flexural stresses due to variation of thermal gradient and wheel load, respectively, cause cracking of rigid pavement. The distress in the pavement structure can be happened because of warping stresses induced by thermal gradient which causes curling effect due to temperature variation. The wheel load resulted flexural stresses which varies with the position and depends upon contact condition and repetition of load at a specific time interval. In the present study, a comparison of stresses of single layered rigid concrete pavement due to thermal load and wheel load have been done with varying slab thicknesses and modulus of subgrade reactions. The pavement has been modeled and analysed using SAP2000 finite element software. During modeling, the single layered rigid concrete pavements comprising of PQC has been considered without any joints at edges. The PQC slab has been considered with dense liquid foundation i.e. elastic. The self weight of pavement has been excluded in the analysis. It has been found that the interior thermal warping stresses are more sensitive with respect to slab thicknesses than modulus of subgrade reactions. It can also be stated that there is significant impact on stress behavior of the pavement due to combined effect of thermal gradient along with wheel load, especially for positive and negative thermal gradient considerations.

Thermally-Induced Deformations and Warpages of Flip-Chip and 2.5D IC Packages Measured by Strain Gauges.

The thermal warpage problems in integrated circuit (IC) packaging exist in both flip-chip and two-and-a-half dimensional integrated circuits (2.5D IC) packages during manufacturing processes and thermal cycling service. This study proposes a simple and easy-to-use strain gauge measurement associated with a beam model theory to determine the thermally induced deformations and warpages of both packages. First, validation and limitations of the beam model theory are presented. Then, the thermally induced out-of-plane deformations for both packages are well described by the finite element method (FEM) simulation with a good consistency to full-field shadow moiré experimental results. The strain gauge measurements were implemented experimentally, and the thermal strain results were found to be well consistent with validated FEM ones. As a result, out-of-plane thermal deformations and warpages of the packages, calculated from the beam model theory with extracted curvature data from the strain gauge, were in reasonably good agreement with those from FEM analysis and shadow moiré measurements. Therefore, the strain gauge method of featuring point strain measurement combined with the beam model theory proved feasible in determining the thermal deformations and warpages of both IC packages.

Quasi-simultaneous 3D printing of muscle-, lung- and bone-equivalent media: a proof-of-concept study.

3D printing is a promising solution for the production of bespoke phantoms and phantom components, for radiotherapy dosimetry and quality assurance (QA) purposes. This proof-of-concept study investigated the use of a dual-head printer to deposit two different filaments (polylactic acid (PLA) and StoneFil PLA-concrete (Formfutura BV, Nijmegen, Netherlands)) at several different in-fill densities, to achieve quasi-simultaneous 3D printing of muscle-, lung- and bone-equivalent media. A Raise 3D Pro 3D printer (Raise 3D Technologies Inc, Irvine, USA) was used to print one thoracic and one cranial phantom slab. Analysis using in-house 3D print QA software showed that the two humanoid phantom slabs geometrically matched the stereolithography (STL) files on which they were based, within 0.3 mm, except in one area of the thoracic slab that was affected by thermal warping by up to 3.4 mm. The 3D printed muscle, lung and bone materials in the two humanoid phantom slabs were approximately radiologically-equivalent to human muscle, lung and bone. In particular, the use of StoneFil with a nominally constant in-fill density of 100% resulted in regions that were approximately inner-bone-equivalent, at kV and MV energies. These regions were bounded by walls that were substantially denser than inner bone, although generally not dense enough to be truly cortical-bone-equivalent. This proof-of-concept study demonstrated a method by which multiple tissue-equivalent materials (eg. muscle-, lung- and bone-equivalent media) can be deposited within one 3D print, allowing complex phantom components to be fabricated efficiently in a clinical setting.

Sn-3.0Ag-0.5Cu/Sn-58Bi composite solder joint assembled using a low-temperature reflow process for PoP technology

Package-on-Package (PoP) is a popular technology for fabricating chipsets of accelerated processing units. However, the coefficient of thermal expansion mismatch between Si chips and polymer substrates induces thermal warpage during the reflow process. As such, the reflow temperature and reliability of solder joints are critical aspects of PoP. Although Sn58Bi is a good candidate for low-temperature processes, its brittleness causes other reliability issues. In this study, an in-situ observation was performed on composite solders (CSs) made of an Sn-3.0Ag-0.5Cu (SAC305) solder and an Sn58Bi solder that were mixed during reflow at temperatures of 170 °C (CS-170), 180 °C (CS-180), and 190 °C (CS-190). The volumes of the mixed-solder regions were in the order of CS-190 > CS-180 > CS-170. A calculated Sn58Bi-SAC305 isoplethal section of the Sn-Ag-Cu-Bi quaternary system was employed to elucidate the melting behavior of CS-190. CS-190 with Sn cyclic twin boundary and Bi phase preferred orientation of [0001] was demonstrated by electron backscatter diffraction. Moreover, Cu/CS-190/Cu joints with a shear strength of 46 MPa were formed. CS-190 can reduce the brittleness of SnBi solder owing to the reduced solid-solution hardening with the decrease in the Bi content. These factors can improve the reliability of PoP technology.

Manufacturing and characterization of novel clutch non-conventional fiber-reinforced composite laminates

In this study the manufacture and characterization of novel non-conventional composite laminates coined as clutch laminates are presented. These carbon/epoxy laminates are manufactured using prepreg slit tape in an automated fiber placement (AFP) machine through tow skips. The AFP process allows for the tailoring of material architecture, resulting in woven-like structures without the need for a loom. These laminates are heterogeneous due to variation of fiber orientation and therefore, the material properties at a given section is a function of in-plane spatial coordinates. The thermal and mechanical behavior is studied where the clutch laminate lay-up pattern is represented with a sub cell approach utilizing 3D shell finite elements where the tows are deposited onto the regions mimicking the AFP course. Experimental results show that post-cure thermal warpage for the clutch carbon/epoxy laminates is significantly reduced when compared to conventional asymmetric laminates while also exhibiting tensile properties comparable to traditional laminates of the same ply counts. Based on the model predictions, the reduction in the warpage is attributed to the spatial variations in the local stacking sequences leading to reduced net deformation.