Bonding method and bonding device for chip contact interconnection
Patent Information
- Application Number
- CN202510141185.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-08
- Publication Date
- 2025-05-13
Smart Images
Figure CN119993849A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor technology, and in particular to a bonding method and a bonding device for interconnecting chip contacts. Background Art
[0002] With the rapid development of semiconductor technology, high-density interconnection processes have shown wide applications and promising prospects in the fields of semiconductor integrated circuits and Micro LED (Micro-light-emitting diode) displays. High-density interconnection processes cover key technologies such as flip-chip, rewiring, 2.5D interconnection and 3D interconnection. In the process of development, the contact size of chip interconnections has shrunk dramatically from tens of microns to several microns, and the contact spacing has also been greatly reduced accordingly, allowing the contact density per unit area to reach 400 to 1,000,000 / mm. 2 .
[0003] However, the continuous improvement of semiconductor integration has brought about technological progress while also triggering a series of severe technical challenges. On the one hand, the increase in I / O contact density and the reduction in size have made the difficulty of permanent and non-permanent connections of contacts exponentially higher. Specifically, the reduction in contact size and the geometric increase in the number of contacts have led to two key problems: first, the interconnection between contacts is very prone to misalignment, which in turn causes a significant decrease in interconnection performance; second, the probability of poor contact has increased significantly, and interference factors such as dust particles that are difficult to avoid during the process are more likely to damage the integrity of the contacts. These two problems have further led to subsequent serious adverse consequences, including the inability of the chip to effectively implement functional testing due to poor contact in non-permanent interconnection scenarios such as CP electrical testing (circuit probing test); and functional failure due to poor contact in permanent interconnection processes such as flip-chip and vertical stacking.
[0004] On the other hand, as the contact size continues to shrink, the position tolerance allowed during interconnection becomes extremely small. The expansion and contraction size changes caused by temperature changes during the interconnection process can easily lead to interconnection alignment failure. For example, in CP electrical testing, as the temperature rises, thermal drift of the probe will occur; and when 3D stacking uses thermal compression bonding (TCB) technology, the contacts of the upper and lower chips will shift. In addition, the warping problem of wafers and chips cannot be ignored, which may also cause deviations between the actual contact position and the theoretical position, thus seriously affecting the accuracy and stability of the interconnection.
[0005] In the existing technical means, whether it is a non-permanent interconnection device (such as a CP electrical test probe station) or a permanent interconnection device (such as a bonding device), an optical alignment method is usually used to achieve contact alignment. In general, it is necessary to introduce at least one position reference mark located outside the contact on the upper and lower contact planes, and use the position reference point as the positioning basis for the plane where the contact is located, and complete the alignment, bonding and interconnection operations by adjusting the position and posture. However, this traditional optical alignment method based on position reference points is an indirect alignment. In high-density, small-size, and large-number contact interconnection scenarios, there are alignment errors. The sources of errors include but are not limited to the position error between the alignment point and the contact group, the relative position error between the contact group points, the posture of the contact group plane, the parallelism, and the error introduced by the deflection; in the face of a series of problems caused by high-density interconnection, it is difficult to meet the increasing demand for high-precision interconnection, and a new technical solution is urgently needed to effectively solve these problems. Summary of the invention
[0006] The object of the present invention is to provide a bonding method and a bonding device for interconnecting chip contacts, which have the advantage of high bonding accuracy.
[0007] To achieve the above object, the present invention provides a chip contact interconnection bonding method, which comprises:
[0008] S10, scanning a first interconnected surface and a second interconnected surface to be connected to each other, obtaining the coordinates of each contact point position of the contact point group on the first interconnected surface in a first coordinate system, and the coordinates of each contact point position of the contact point group on the second interconnected surface in a second coordinate system;
[0009] S30, taking the first coordinate system where the first interconnected surface is located as a reference, transforming the second interconnected surface into the first coordinate system to obtain the coordinates of each contact point of the second interconnected surface in the first coordinate system;
[0010] S40, guiding the second interconnection surface to move relative to the first interconnection surface, so that the first interconnection surface and the second interconnection surface are bonded to each other at a bonding temperature.
[0011] Optionally, before step S30, the method further includes step S20, wherein the first expansion coefficient matrix T1 is used to perform thermal compensation on each contact of the contact group on the first interconnection surface according to the temperature difference between the bonding temperature and the temperature during scanning to obtain (x′ ij , y′ ij ); using the second expansion coefficient matrix T2 to thermally compensate each contact of the contact group on the second interconnect surface to obtain (s′ ij , t′ ij ).
[0012] Optionally, step S30 specifically includes: taking the first coordinate system where the first interconnected surface is located as a reference system, and converting a point (s′) on the second interconnected surface in the second coordinate system into ij , t′ ij ) is rotated, translated, and flipped to obtain a point (s″) on the second interconnected surface in the first coordinate system. ij , t″ ij ),have Rotation Matrix Wherein θ is the rotation angle of the second coordinate system, and (u, v) is the translation amount of the second coordinate system.
[0013] Optionally, in step S30, it also includes step S31, calculating the overlap rate between each contact of the contact group on the first interconnection surface and the second interconnection surface. If the overlap rate meets the bonding requirements, proceed to the next step; if the overlap rate does not meet the bonding requirements, replace the first interconnection surface or the second interconnection surface and return to S10.
[0014] Optionally, in step S30, the rotation matrix H is calculated according to the minimum value of the root mean square of the distances between corresponding contact points on the contact point groups on the first interconnection surface and the second interconnection surface.
[0015] Optionally, in the first coordinate system, the coordinates of each contact point on the first interconnection surface after thermal compensation are (x′ ij , y′ ij ), the coordinates of each contact point on the second interconnection surface in the first coordinate system are (s″ ij , t″ ij ); Calculating the minimum value of the root mean square of the distance between each corresponding contact point on the contact point group on the first interconnection surface and the second interconnection surface includes finding The minimum value of can be simplified to finding the minimum value of F(θ, u, v), and the rotation matrix H is determined according to θ and (u, v) when F(θ, u, v) obtains the minimum value.
[0016] Optionally, the minimum value of F(θ, u, v) is obtained by the steepest descent method.
[0017] Optionally, in step S31, calculating the overlap rate between each contact point of the contact point group on the first interconnection surface and the second interconnection surface includes calculating an overlap area s of a contact point on the first interconnection surface and a corresponding contact point on the second interconnection surface. ij The overlap ratio is the ratio of the overlap area to the default area of the contact point. Where k is the overlap rate, s ij is the overlapping area, s is the default area; when k is greater than the overlap threshold K, the overlap requirement is met; when k is less than the overlap threshold K, the overlap requirement is not met.
[0018] Optionally, after step S10, step S11 is also included, detecting whether each contact of the contact group on the first interconnection surface and the second interconnection surface meets the mutual bonding standard. If so, proceed to the next step; if not, replace the first interconnection surface or the second interconnection surface and return to S10.
[0019] Optionally, in step S11, the situations where the first interconnection surface and the second interconnection surface do not meet the mutual bonding standard include: the contact is incomplete, the coordinates of the first interconnection surface or the second interconnection surface obtained by scanning are different from the design coordinates, and there are foreign objects on the first interconnection surface or the second interconnection surface.
[0020] The present invention also provides a bonding device for interconnecting chip contacts, the bonding device comprising:
[0021] A control module, wherein a readable storage medium is provided in the control module, on which a computer program is stored, and when the computer program is executed by the processor, the bonding method as described above is implemented;
[0022] A first clamping module, used for clamping a first object to be bonded having a first interconnected surface;
[0023] A second clamping module, used for clamping a second object to be bonded having a second interconnected surface;
[0024] A contact scanning module, electrically connected to the control module, and configured to scan the first interconnection surface and the second interconnection surface;
[0025] A driving module is electrically connected to the first clamping module, the second clamping module and the control module respectively, and is used to drive the first clamping module and / or the second clamping module according to the instruction of the control module to bond the first object to be bonded and the second object to be bonded.
[0026] Optionally, the control module is further used to perform thermal compensation on the first interconnection surface and the second interconnection surface.
[0027] In summary, compared with the prior art, the chip contact interconnection bonding method and bonding device provided by the present invention have the following beneficial effects:
[0028] The chip contact interconnection bonding method of the present invention directly scans the coordinates of the positions of each contact on the first interconnection surface and the second interconnection surface, and adjusts the relative position of the first interconnection surface and the second interconnection surface according to the actual position of each contact, thereby avoiding the situation where the reference point is aligned but the actual contact is not aligned due to the relative change of the reference point and the contact position, thereby achieving high-precision bonding between the two. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 The figure is a flow chart of a bonding method according to an embodiment of the present invention.
[0030] Figure 2 Schematic diagram of the first interconnection surface and the second interconnection surface in each step of the bonding method in embodiment 1 of the present invention.
[0031] Figure 3 It is a schematic diagram of calculating the overlap ratio in the bonding method according to the first embodiment of the present invention.
[0032] Figure 4 Schematic diagram of the bonding device of the present invention.
[0033] Figure 5 This is a flow chart of a bonding method according to a second embodiment of the present invention.
[0034] Description of reference numerals:
[0035] Bonding device 10
[0036] Control module 100
[0037] The first clamping module 110
[0038] The second clamping module 120
[0039] Contact scanning module 130
[0040] Driver module 140 DETAILED DESCRIPTION
[0041] The following will be combined with the attached embodiment of the present invention Figure 1 ~Attached Figure 5 , the technical solutions, structural features, objectives achieved and effects in the embodiments of the present invention are described in detail.
[0042] It should be noted that the drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the embodiments of the present invention, and are not used to limit the conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention.
[0043] It should be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only the elements explicitly listed, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.
[0044] Example 1
[0045] like Figure 1 and Figure 2 As shown, the present invention provides a bonding method for interconnecting chip contacts, the bonding method comprising:
[0046] S10, scanning the first interconnected surface and the second interconnected surface to be connected to each other, and obtaining the position coordinates (x ij ,y ij ), and obtain the coordinates of each contact point of the contact point group on the second interconnection surface in the second coordinate system (s ij , t ij ). As one embodiment, the first interconnection surface may be a wafer or a chip, and the second interconnection surface is a chip. A wafer refers to a silicon wafer used to manufacture silicon semiconductor integrated circuits, which is usually a circular thin sheet; and a chip is a part cut from a wafer.
[0047] S20, according to the temperature difference between the bonding temperature and the temperature during scanning, the first expansion coefficient matrix T1 is used to perform thermal compensation on the first interconnection surface; according to the thermal expansion characteristics of the material of the second interconnection surface itself, the second expansion coefficient matrix T2 is used to perform thermal compensation on the second interconnection surface. Since the first interconnection surface and the second interconnection surface need to be heated to the bonding temperature during subsequent bonding, and they are at room temperature during scanning in S10, and the temperature during bonding is much higher than the temperature during scanning, so that the positions of each contact in the contact group on the first interconnection surface and the second interconnection surface will be thermally deformed relative to the scanning during bonding. If bonding is still performed according to the contact positions determined during scanning, the two cannot be well bonded. Therefore, in this step, the contact positions of the contact groups on the first interconnection surface and the second interconnection surface are thermally compensated, and thermal compensation is performed according to the thermal expansion characteristics of the materials of the first interconnection surface and the second interconnection surface, and the contact positions of the contact groups on the first interconnection surface and the second interconnection surface are converted from the coordinates at room temperature during scanning to the coordinates at the bonding temperature through thermal compensation.
[0048] Specifically, the expansion coefficient matrix T during thermal compensation (T is known and is only related to the material properties of the first interconnection surface or the second interconnection surface itself), where the initial coordinates (x ij ,y ij ) after thermal expansion and deformation, the coordinate is (x′ ij , y′ ij ),Right now In the second coordinate system, the initial contact point coordinates (s ij , t ij ), after thermal expansion and deformation, the coordinates become (s′ ij , t′ ij ),Right now
[0049] Since the temperature of the contacts on the first interconnection surface and the second interconnection surface can reach 300-400°C when bonding at high temperature, and the positions of the contact groups on the first interconnection surface and the second interconnection surface are scanned at room temperature in step S10. The temperature difference between the scanning and the actual bonding can reach more than 300°C. The contact density of the contact group on the first interconnection surface and the second interconnection surface is extremely high, and the contact area of a single contact is extremely small. If the first interconnection surface and the second interconnection surface are not thermally compensated, the thermal deformation caused by the temperature change will cause the corresponding points of the contact group on the first interconnection surface and the second interconnection surface to be unable to align, and ultimately lead to bonding failure. Therefore, the first interconnection surface and the second interconnection surface must be thermally compensated to obtain the accurate position of each contact during high-temperature bonding, ensure successful bonding, and improve bonding quality.
[0050] S30, using the first coordinate system where the first interconnected surface is located as a reference, transforming the second interconnected surface into the first coordinate system, and obtaining the coordinates of each contact point on the second interconnected surface in the first coordinate system. Specifically, using the first coordinate system where the first interconnected surface is located as a reference system, the point (s′) on the second interconnected surface after thermal compensation in the second coordinate system is converted into the coordinate system of the first interconnected surface. ij , t′ ij ) After rotation, translation and flipping, the thermally compensated point (s″) on the second interconnection surface in the first coordinate system is obtained. ij , t″ ij ),have Rotation Matrix Where θ is the rotation angle of the second coordinate system, and (u, v) is the translation amount of the second coordinate system.
[0051] During the scanning process in S10, the relative relationship between the first interconnection surface and the second interconnection surface is not established, but the contact position coordinates of the contact groups on the first interconnection surface and the second interconnection surface are scanned in their respective coordinate systems. In this step, by converting the second interconnection surface to the first coordinate system where the first interconnection surface is located, the relative position relationship between the second interconnection surface and the first interconnection surface can be adjusted in the same coordinate system later, so as to achieve accurate bonding between the two.
[0052] S40, guide the second interconnection surface to move relative to the first interconnection surface, so that the first interconnection surface and the second interconnection surface are bonded to each other at the bonding temperature. In step S30, the second interconnection surface has been converted to the first coordinate system where the first interconnection surface is located. In this step, the relative movement between the first interconnection surface and the second interconnection surface is controlled by the driving module, and the corresponding points of the contact groups on the first interconnection surface and the second interconnection surface in the first coordinate system are aligned to achieve precise alignment of the first interconnection surface and the second interconnection surface at high temperature, and achieve precise bonding of the contact groups on the first interconnection surface and the second interconnection surface.
[0053] As a preferred embodiment, after step S10, step S11 is further included, detecting whether each contact of the contact group on the first interconnection surface and the second interconnection surface meets the mutual bonding standard. If so, proceed to the next step; if not, replace the first interconnection surface or the second interconnection surface and return to S10. The situation where the first interconnection surface and the second interconnection surface do not meet the mutual bonding standard includes the situation where the contact is incomplete, the coordinates of the scanned first interconnection surface or the second interconnection surface are different from the designed coordinates, and there are foreign objects on the first interconnection surface or the second interconnection surface.
[0054] In this embodiment, by adding a step of detecting the contact quality of the contact group on the first interconnection surface and the second interconnection surface after scanning, the contact distribution of the contact group on the first interconnection surface and the second interconnection surface is scanned before entering the subsequent steps such as thermal compensation. If it is determined that the contact distribution of the contact group on any of the latter surfaces of the first interconnection surface or the second interconnection surface does not meet the bonding requirements, the first interconnection surface or the second interconnection surface that does not meet the requirements is discarded to avoid the first interconnection surface or the second interconnection surface that does not meet the requirements from entering the subsequent bonding process, resulting in bonding failure. In the bonding process of the first interconnection surface and the second interconnection surface, the first interconnection surface and the second interconnection surface that need to be bonded to each other must both meet the bonding requirements, and accurate alignment in the subsequent steps can achieve accurate bonding between the two. If one or both of the first interconnection surface or the second interconnection surface do not meet the bonding requirements, even if they are aligned in the subsequent steps, accurate bonding cannot be achieved, resulting in bonding failure.
[0055] As a preferred embodiment, step S30 also includes step S31, calculating the overlap rate between each contact of the contact group on the first interconnection surface and the second interconnection surface. If the overlap rate meets the bonding requirements, the next step is entered; if the overlap rate does not meet the bonding requirements, the first interconnection surface or the second interconnection surface is replaced and the process returns to S10. In this embodiment, a step of calculating the overlap rate of the corresponding contacts of the contact group on the first interconnection surface and the second interconnection surface is added in step S30. It is inevitable that there will be deviations between the first interconnection surface and the second interconnection surface during the manufacturing process. If the deviations of the two are in opposite directions, even if the contact distribution of the contact group on the first interconnection surface and the second interconnection surface meets the contact position distribution requirements respectively, there is a situation that the bonding cannot be successfully completed in the end. Therefore, in this step, the overlap rate of the contacts at the corresponding positions on the first interconnection surface and the second interconnection surface after scanning is calculated, that is, whether the first interconnection surface and the second interconnection surface that meet the requirements respectively can be successfully bonded in the subsequent process is considered. If the bonding cannot be successfully completed, the first interconnection surface or the second interconnection surface is replaced to improve the success rate of subsequent bonding.
[0056] In step S30, the rotation matrix H is calculated based on the minimum value of the root mean square of the distances between the corresponding contact points on the contact point groups on the first interconnection surface and the second interconnection surface.
[0057] Specifically, the coordinates of each contact point on the first interconnect surface after thermal compensation in the first coordinate system are (x′ ij , y′ ij ), the coordinates of each contact point on the second interconnection surface after thermal compensation in the first coordinate system are (s″ ij , t″ ij );Calculate the minimum value of the root mean square of the distance between the corresponding contacts on the contact group on the first interconnection surface and the second interconnection surface, that is, The minimum value of , where a and b are the number of contacts in the horizontal and vertical directions on the first interconnection surface and the second interconnection surface, respectively, that is, the minimum value of the sum of the center position deviations between the corresponding contacts on the first interconnection surface and the second interconnection surface is calculated. In the formula, the point (s″) on the second interconnection surface after thermal compensation in the first coordinate system ij , t″ ij) is only related to the rotation angle θ of the second coordinate system and the translation amount (u, v) of the second coordinate system, and the rotation angle θ of the second coordinate system and the translation amount (u, v) of the second coordinate system are quantities that can be adjusted according to actual conditions. Therefore, it can be simplified to find the minimum value of F(θ, u, v). The function F(θ, u, v) is the rotation angle θ of the second coordinate system and the translation amount (u, v) of the second coordinate system as independent variables, and the minimum value of the function F(θ, u, v) is found, that is, when the overall distance between the corresponding contact positions on the first interconnected surface and the second interconnected surface is the smallest, θ and (u, v) at the minimum value can be used as parameters in the rotation matrix H that guides the relative movement of the first interconnected surface and the second interconnected surface in step S30.
[0058] As a preferred embodiment, the minimum value of F(θ, u, v) is obtained by the steepest descent method. The basic idea of the steepest descent method is to find the minimum value of the function along the direction where the function value decreases fastest. It has the advantages of being simple, intuitive, easy to understand and implement.
[0059] In other embodiments, the minimum value of F(θ, u, v) may also be obtained by other algorithms, such as a conjugate gradient method or a genetic algorithm, as long as the minimum value can be obtained, and no limitation is made here.
[0060] In step S31, the overlap ratio between each contact point of the contact point group on the first interconnection surface and the second interconnection surface is calculated, which can be obtained by calculating the overlap area s of the contact point on the first interconnection surface and the corresponding contact point on the second interconnection surface. ij Realization. Figure 3 As shown, Figure 3 The white circle on the right side of the middle represents a contact point on the first interconnection surface, and the black circle represents the corresponding contact point on the second interconnection surface. The overlapping part of the white circle and the black circle represents the overlapping area s. ij The overlap ratio is the ratio of the overlap area to the default area of the contact. Where k is the overlap rate, s ij is the overlapping area, s is the default area; when k is greater than the overlap threshold K, the overlap requirement is met, and when k is less than the overlap threshold K, the overlap requirement is not met. If the overlap requirement is not met, the first interconnection surface or the second interconnection surface is replaced.
[0061] In general scenarios, the overlap threshold K can be greater than 2 / 3. In some scenarios where there are no strict requirements, the overlap threshold K can be greater than 1 / 3. The values of the overlap threshold K are given as examples here. The specific value can be selected according to the actual situation and does not constitute a limitation on the value range of the overlap threshold K. Among them, the overlap threshold K is greater than 2 / 3 means that the overlap of each corresponding contact on the first interconnection surface and the second interconnection surface needs to be greater than 2 / 3.
[0062] The chip contact interconnection bonding method of the present invention does not require the aid of external reference points, but directly scans the interconnection surface and calculates the position distribution of the contact group, and then calculates the overlap rate of the maximum contact group. In the process of calculating the maximum overlap rate, the parameters of the rotation matrix of the relative rotational motion of the first interconnection surface and the second interconnection surface are also obtained, so that the driving module drives the second interconnection surface to move relative to the first interconnection surface according to the calculated rotation angle θ and the translation amount (u, v) of the second coordinate system, so as to achieve the final alignment contact or bonding, and the interconnection and docking of the first interconnection surface and the second interconnection surface.
[0063] like Figure 4 As shown, the present invention further provides a bonding device 10 for interconnecting chip contacts. The bonding device 10 includes a control module 100 , a first clamping module 110 , a second clamping module 120 , a contact scanning module 130 and a driving module 140 .
[0064] The control module 100 is provided with a readable storage medium, on which a computer program is stored. When the computer program is executed by the processor, the bonding method as described above is implemented. The control module 100 is used to implement overall control. At the beginning of bonding, the control module 100 is used to control the contact scanning module 130 to scan the first interconnection surface and the second interconnection surface. After the scanning is completed, the control module 100 is also used to implement thermal compensation for thermal deformation of the first interconnection surface and the second interconnection surface under high-temperature bonding; then the control module 100 calculates the maximum overlap rate of the first interconnection surface and the second interconnection surface while obtaining the optimal rotation matrix, and controls the driving module 140 to drive the first clamping module 110 and the second clamping module 120 to move according to the rotation matrix to bond the first interconnection surface and the second interconnection surface.
[0065] The first clamping module 110 is used to clamp a first object to be bonded having a first interconnecting surface. The second clamping module 120 is used to clamp a second object to be bonded having a second interconnecting surface. The contact scanning module 130 is electrically connected to the control module 100, and the contact scanning module 130 is used to scan the first interconnecting surface and the second interconnecting surface, and transmit the contact position information of the first interconnecting surface and the second interconnecting surface obtained by scanning to the control module 100.
[0066] The driving module 140 is electrically connected to the first clamping module 110, the second clamping module 120 and the control module 100 respectively, and is used to drive the first clamping module 110 and / or the second clamping module 120 according to the instruction of the control module 100 to bond the first object to be bonded and the second object to be bonded.
[0067] The bonding device 10 may be a CP electrical testing (circuit probing test) device, a temporary transfer device, a permanent chip bonding device, a wafer bonding device 10 , etc., which is only used as an example here and does not limit the specific type of the bonding device 10 .
[0068] Example 2
[0069] like Figure 5 As shown, the present invention provides a bonding method for interconnecting chip contacts, the bonding method comprising:
[0070] S10, scanning the first interconnected surface and the second interconnected surface to be connected to each other, and obtaining the position coordinates (x ij ,y ij ), and obtain the coordinates of each contact point of the contact point group on the second interconnection surface in the second coordinate system (s ij , t ij ). As one embodiment, the first interconnection surface may be a wafer or a chip, and the second interconnection surface is a chip. A wafer refers to a silicon wafer used to manufacture silicon semiconductor integrated circuits, which is usually a circular thin sheet; and a chip is a part cut from a wafer.
[0071] S30, based on the first coordinate system where the first interconnected surface is located, the second interconnected surface is transformed into the first coordinate system to obtain the coordinates (s′) of each contact point on the second interconnected surface in the first coordinate system. ij , t′ ij Specifically, taking the first coordinate system where the first interconnected surface is located as the reference system, the point (s ij , t ij ) After rotation, translation, and flipping, we get the point (s′) on the second interconnected surface in the first coordinate system. ij , t′ ij ),have Rotation Matrix Where θ is the rotation angle of the second coordinate system, and (u, v) is the translation amount of the second coordinate system.
[0072] During the scanning process in S10, the relative relationship between the first interconnection surface and the second interconnection surface is not established, but the contact position coordinates of the contact groups on the first interconnection surface and the second interconnection surface are scanned in their respective coordinate systems. In this step, by converting the second interconnection surface to the first coordinate system where the first interconnection surface is located, the relative position relationship between the second interconnection surface and the first interconnection surface can be adjusted in the same coordinate system later, so as to achieve accurate bonding between the two.
[0073] S40, guide the second interconnection surface to move relative to the first interconnection surface, so that the first interconnection surface and the second interconnection surface are bonded to each other at the bonding temperature. In step S30, the second interconnection surface has been converted to the first coordinate system where the first interconnection surface is located. In this step, the relative movement between the first interconnection surface and the second interconnection surface is controlled by the driving module, and the corresponding points of the contact groups on the first interconnection surface and the second interconnection surface in the first coordinate system are aligned to achieve precise alignment of the first interconnection surface and the second interconnection surface at room temperature, and achieve precise bonding of the contact groups on the first interconnection surface and the second interconnection surface.
[0074] As a preferred embodiment, after step S10, step S11 is further included, detecting whether each contact of the contact group on the first interconnection surface and the second interconnection surface meets the mutual bonding standard. If so, proceed to the next step; if not, replace the first interconnection surface or the second interconnection surface and return to S10. The situation where the first interconnection surface and the second interconnection surface do not meet the mutual bonding standard includes the situation where the contact is incomplete, the coordinates of the scanned first interconnection surface or the second interconnection surface are different from the designed coordinates, and there are foreign objects on the first interconnection surface or the second interconnection surface.
[0075] In this embodiment, by adding a step of detecting the contact quality of the contact group on the first interconnection surface and the second interconnection surface after scanning, the contact distribution of the contact group on the first interconnection surface and the second interconnection surface is scanned before entering the subsequent steps such as setting the bonding agent. If it is determined that the contact distribution of the contact group on any of the latter surfaces of the first interconnection surface or the second interconnection surface does not meet the bonding requirements, the first interconnection surface or the second interconnection surface that does not meet the requirements is discarded to avoid the first interconnection surface or the second interconnection surface that does not meet the requirements from entering the subsequent bonding process, resulting in bonding failure. In the bonding process of the first interconnection surface and the second interconnection surface, the first interconnection surface and the second interconnection surface that need to be bonded to each other need to meet the bonding requirements, and accurate alignment is performed in the subsequent steps to achieve accurate bonding between the two. If one or both of the first interconnection surface or the second interconnection surface do not meet the bonding requirements, even if they are aligned in the subsequent steps, accurate bonding cannot be achieved, resulting in bonding failure.
[0076] As a preferred embodiment, in step S30, it also includes step S31, calculating the overlap rate between each contact of the contact group on the first interconnection surface and the second interconnection surface. If the overlap rate meets the bonding requirements, the next step is entered; if the overlap rate does not meet the bonding requirements, the first interconnection surface or the second interconnection surface is replaced and the process returns to S10. In this embodiment, a step of calculating the overlap rate of the corresponding contacts of the contact group on the first interconnection surface and the second interconnection surface is added in step S30. It is inevitable that there will be deviations between the first interconnection surface and the second interconnection surface during the manufacturing process. If the deviations of the two are in opposite directions, even if the contact distribution of the contact group on the first interconnection surface and the second interconnection surface meets the contact position distribution requirements respectively, there is a situation that the bonding cannot be successfully completed in the end. Therefore, in this step, the overlap rate of the contacts at the corresponding positions on the first interconnection surface and the second interconnection surface after scanning is calculated, that is, whether the first interconnection surface and the second interconnection surface that meet the requirements respectively can be successfully bonded in the subsequent process is considered. If the bonding cannot be successfully completed, the first interconnection surface or the second interconnection surface is replaced to improve the success rate of subsequent bonding.
[0077] In step S30, the rotation matrix H is calculated based on the minimum value of the root mean square of the distances between the corresponding contact points on the contact point groups on the first interconnection surface and the second interconnection surface.
[0078] Specifically, the coordinates of each contact point on the first interconnection surface in the first coordinate system are (x ij ,y ij ), the coordinates of each contact point on the second interconnection surface in the first coordinate system are (s′ ij , t′ ij );Calculate the minimum value of the root mean square of the distance between the corresponding contacts on the contact group on the first interconnection surface and the second interconnection surface, that is, The minimum value of , where a and b are the number of contacts in the horizontal and vertical directions on the first interconnection surface and the second interconnection surface, respectively, that is, the minimum value of the sum of the center position deviations between the corresponding contacts on the first interconnection surface and the second interconnection surface is calculated. ij , t′ ij ) is only related to the rotation angle θ of the second coordinate system and the translation amount (u, v) of the second coordinate system, and the rotation angle θ of the second coordinate system and the translation amount (u, v) of the second coordinate system are quantities that can be adjusted according to actual conditions. Therefore, it can be simplified to find the minimum value of F(θ, u, v). The function F(θ, u, v) is the rotation angle θ of the second coordinate system and the translation amount (u, v) of the second coordinate system as independent variables, and the minimum value of the function F(θ, u, v) is found, that is, when the overall distance between the corresponding contact positions on the first interconnected surface and the second interconnected surface is the smallest, θ and (u, v) at the minimum value can be used as parameters in the rotation matrix H that guides the relative movement of the first interconnected surface and the second interconnected surface in step S30.
[0079] As a preferred embodiment, the minimum value of F(θ, u, v) is obtained by the steepest descent method. The basic idea of the steepest descent method is to find the minimum value of the function along the direction where the function value decreases fastest. It has the advantages of being simple, intuitive, easy to understand and implement.
[0080] In other embodiments, the minimum value of F(θ, u, v) may also be obtained by other algorithms, such as a conjugate gradient method or a genetic algorithm, as long as the minimum value can be obtained, and no limitation is made here.
[0081] In step S31, the overlap ratio between each contact point of the contact point group on the first interconnection surface and the second interconnection surface is calculated, which can be obtained by calculating the overlap area s of the contact point on the first interconnection surface and the corresponding contact point on the second interconnection surface. ij accomplish. Figure 3 The white circle on the right side of the middle represents a contact point on the first interconnection surface, and the black circle represents the corresponding contact point on the second interconnection surface. The overlapping part of the white circle and the black circle represents the overlapping area s. ij The overlap ratio is the ratio of the overlap area to the default area of the contact. Where k is the overlap rate, s ij is the overlapping area, s is the default area; when k is greater than the overlap threshold K, the overlap requirement is met, and when k is less than the overlap threshold K, the overlap requirement is not met. If the overlap requirement is not met, the first interconnection surface or the second interconnection surface is replaced.
[0082] In general scenarios, the overlap threshold K can be greater than 2 / 3. In some scenarios where there are no strict requirements, the overlap threshold K can be greater than 1 / 3. The values of the overlap threshold K are given as examples here. The specific value can be selected according to the actual situation and does not constitute a limitation on the value range of the overlap threshold K. Among them, the overlap threshold K is greater than 2 / 3 means that the overlap of each corresponding contact on the first interconnection surface and the second interconnection surface needs to be greater than 2 / 3.
[0083] In the present embodiment, a bonding method for interconnecting chip contacts at room temperature does not require the aid of external reference points, but directly scans the interconnection surface and calculates the position distribution of the contact group, and then calculates the maximum overlap rate of the contact group. In the process of calculating the maximum overlap rate, the parameters of the rotation matrix of the relative rotational motion of the first interconnection surface and the second interconnection surface are also obtained, so that the driving module drives the second interconnection surface to move relative to the first interconnection surface according to the calculated rotation angle θ and the translation amount (u, v) of the second coordinate system, so as to achieve the final alignment contact or bonding, and the interconnection and docking of the first interconnection surface and the second interconnection surface.
[0084] like Figure 4As shown, the present invention also provides a bonding device 10 for interconnecting chip contacts at room temperature. The bonding device 10 includes a control module 100 , a first clamping module 110 , a second clamping module 120 , a contact scanning module 130 and a driving module 140 .
[0085] The control module 100 is provided with a readable storage medium, on which a computer program is stored. When the computer program is executed by the processor, the bonding method as described above is implemented. The control module 100 is used to implement overall control. At the beginning of bonding, the control module 100 is used to control the contact scanning module 130 to scan the first interconnection surface and the second interconnection surface; then the control module 100 calculates the maximum overlap rate of the first interconnection surface and the second interconnection surface while obtaining the optimal rotation matrix, and controls the driving module 140 to drive the first clamping module 110 and the second clamping module 120 to move according to the rotation matrix to bond the first interconnection surface and the second interconnection surface.
[0086] The first clamping module 110 is used to clamp a first object to be bonded having a first interconnecting surface. The second clamping module 120 is used to clamp a second object to be bonded having a second interconnecting surface. The contact scanning module 130 is electrically connected to the control module 100, and the contact scanning module 130 is used to scan the first interconnecting surface and the second interconnecting surface, and transmit the contact position information of the first interconnecting surface and the second interconnecting surface obtained by scanning to the control module 100.
[0087] The driving module 140 is electrically connected to the first clamping module 110, the second clamping module 120 and the control module 100 respectively, and is used to drive the first clamping module 110 and / or the second clamping module 120 according to the instruction of the control module 100 to bond the first object to be bonded and the second object to be bonded.
[0088] The bonding device 10 may be a CP electrical testing (circuit probing test) device, a temporary transfer device, a permanent chip bonding device, a wafer bonding device 10 , etc., which is only used as an example here and does not limit the specific type of the bonding device 10 .
[0089] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.
Claims
1. A bonding method for interconnecting lower chip contacts, characterized in that: The bonding method comprises: S10, scanning the first interconnected surface and the second interconnected surface to be connected to each other, and obtaining the position coordinates (x ij ,y ij ), and the coordinates of the contact positions of the contact groups on the second interconnection surface in the second coordinate system (s ij , t ij ); S30, taking the first coordinate system where the first interconnected surface is located as a reference, transforming the second interconnected surface into the first coordinate system to obtain the coordinates of each contact point of the second interconnected surface in the first coordinate system; S40, guiding the second interconnection surface to move relative to the first interconnection surface, so that the first interconnection surface and the second interconnection surface are bonded to each other at a bonding temperature.
2. The bonding method according to claim 1, characterized in that Before step S30, the method further includes step S20, wherein the first expansion coefficient matrix T1 is used to perform thermal compensation on each contact point of the contact point group on the first interconnection surface according to the temperature difference between the bonding temperature and the temperature during scanning to obtain (x′ ij , y′ ij ); using the second expansion coefficient matrix T2 to thermally compensate each contact of the contact group on the second interconnect surface to obtain (s′ ij , t′ ij ).
3. The bonding method according to claim 2, characterized in that: Step S30 specifically includes: taking the first coordinate system where the first interconnected surface is located as a reference system, converting the point (s′) on the second interconnected surface in the second coordinate system ij , t′ ij ) is rotated, translated, and flipped to obtain a point (s″) on the second interconnected surface in the first coordinate system. ij , t″ ij ),have Rotation Matrix Wherein θ is the rotation angle of the second coordinate system, and (u, v) is the translation amount of the second coordinate system.
4. The bonding method according to claim 3, characterized in that: In step S30, it also includes step S31, calculating the overlap rate between each contact of the contact group on the first interconnection surface and the second interconnection surface. If the overlap rate meets the bonding requirements, proceed to the next step; if the overlap rate does not meet the bonding requirements, replace the first interconnection surface or the second interconnection surface and return to S10.
5. The bonding method according to claim 4, characterized in that: In step S30, the rotation matrix H is calculated according to the minimum value of the root mean square of the distances between the corresponding contact points on the contact point groups on the first interconnection surface and the second interconnection surface.
6. The bonding method according to claim 5, characterized in that: The coordinates of each contact point on the first interconnection surface after thermal compensation in the first coordinate system are (x′ ij , y′ ij ), the coordinates of each contact point on the second interconnection surface in the first coordinate system are (s″ ij , t″ ij ); Calculating the minimum value of the root mean square of the distance between each corresponding contact point on the contact point group on the first interconnection surface and the second interconnection surface includes finding The minimum value of can be simplified to finding the minimum value of F(θ, u, v), and the rotation matrix H is determined according to θ and (u, v) when F(θ, u, v) obtains the minimum value.
7. The bonding method according to claim 6, characterized in that: The minimum value of F(θ, u, v) is obtained by the steepest descent method.
8. The bonding method according to claim 6, characterized in that: In step S31, calculating the overlap rate between each contact point of the contact point group on the first interconnection surface and the second interconnection surface includes calculating the overlap area s of the contact point on the first interconnection surface and the corresponding contact point on the second interconnection surface. ij The overlap ratio is the ratio of the overlap area to the default area of the contact point. Where k is the overlap rate, s ij is the overlapping area, s is the default area; when k is greater than the overlap threshold K, the overlap requirement is met; when k is less than the overlap threshold K, the overlap requirement is not met.
9. The bonding method according to claim 1, characterized in that: After step S10, the method further includes step S11, detecting whether the contacts of the contact groups on the first interconnection surface and the second interconnection surface meet the mutual bonding standard. If so, proceed to the next step; if not, replace the first interconnection surface or the second interconnection surface and return to S10.
10. The bonding method according to claim 9, characterized in that: In step S11, the situations where the first interconnection surface and the second interconnection surface do not meet the mutual bonding standard include: the contact is incomplete, the coordinates of the first interconnection surface or the second interconnection surface obtained by scanning are different from the designed coordinates, and there are foreign objects on the first interconnection surface or the second interconnection surface.
11. A bonding device for interconnecting chip contacts, characterized in that: The bonding device comprises: A control module, wherein a readable storage medium is provided in the control module, on which a computer program is stored, and when the computer program is executed by a processor, the bonding method according to any one of claims 1 to 10 is implemented; A first clamping module, used for clamping a first object to be bonded having a first interconnected surface; A second clamping module, used for clamping a second object to be bonded having a second interconnected surface; A contact scanning module, electrically connected to the control module, and configured to scan the first interconnection surface and the second interconnection surface; A driving module is electrically connected to the first clamping module, the second clamping module and the control module respectively, and is used to drive the first clamping module and / or the second clamping module according to the instruction of the control module to bond the first object to be bonded and the second object to be bonded.
12. The chip contact interconnection bonding device according to claim 11, characterized in that: The control module is also used to perform thermal compensation on the first interconnection surface and the second interconnection surface.