Lead frame and packaged semiconductor
By setting long pins on the lead frame, the space limitation problem caused by the simple pin structure is solved, enabling safer and more reliable chip connection, adapting to changing chip designs, and improving production efficiency.
Patent Information
- Application Number
- CN202423228180.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2034-12-26
AI Technical Summary
Traditional leadframe designs have simple pin structures, resulting in limited pad space, making it difficult to meet the requirements of subsequent wire bonding processes. This can easily cause the ceramic tip to collide with the chip, affecting bonding quality and safety.
The design extends some pins towards the edge of the frame body to form long pins. The combination of long and short pins provides additional electrical connection space to accommodate the connection needs of chips of different sizes and layouts.
It improves the versatility and applicability of lead frames, reduces operational risks during bonding, ensures the safety and reliability of bonding, adapts to diverse chip designs, reduces short-circuit risks, and improves production efficiency.
Smart Images
Figure CN223728776U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of chip welding, and further relates to a lead frame and a packaged semiconductor. BACKGROUND
[0002] In traditional semiconductor packaging technology, the connection between the chip and the lead frame is achieved through bonding technology. The lead frame, as a key structural material for semiconductor packaging, mainly serves to support the chip and transmit electrical signals.
[0003] However, the current lead frame design has some limitations, especially in the setting of the pin structure. For example, many structures use a simple six-short-pin design, which limits the pad space and makes it difficult to meet the requirements of subsequent wire bonding processes. Specifically, insufficient space may cause the ceramic nozzle to accidentally collide with the chip during operation, which not only damages the fragile chip but also affects the bonding quality. CONTENT OF THE INVENTION
[0004] To solve the above technical problems, the purpose of the present application is to provide a lead frame and a packaged semiconductor, which optimizes the structure of the lead frame to provide more area space and meet the subsequent production requirements.
[0005] To achieve the above purpose, the present application provides a lead frame, comprising:
[0006] a frame body;
[0007] a plurality of pins, respectively arranged on the frame body to form a welding area for electrical connection of the chip through the plurality of pins;
[0008] In the plurality of pins, part of the pins extend to the edge of the frame body to form long pins, and the rest of the pins are short pins, and the relative length of the long pins is greater than that of the short pins, thereby providing additional space for electrical connection of the chip.
[0009] In some embodiments, the plurality of pins are respectively arranged on opposite side edges of the frame body along a first direction, and the first direction is parallel to the extension direction of one of the central axes of the frame body.
[0010] In some embodiments, on the frame body, the edge where the starting end of the pin is not arranged includes a first edge and a second edge, and the first edge and the second edge are oppositely arranged.
[0011] Part of the pins located on one side edge of the frame body extend to the first edge, and part of the pins located on the other side edge of the frame body extend to the second edge to form long pins on the lead frame; or,
[0012] The partial pins located on different side edges of the frame body extend to the first edge or the second edge simultaneously to form long pins on the lead frame.
[0013] In some embodiments, the pins are bent at least once when extending to the first edge or the second edge, and are staggered with the rest of the pins to form the long pins.
[0014] In some embodiments, the number of the pins is at least six, and at least three pins are arranged on a corresponding side edge of the frame body.
[0015] In some embodiments, the number of the long pins is at least one among the pins on the same edge of the frame body;
[0016] Any pin between the first pin and the last pin is arranged as the long pin;
[0017] And / or, the first pin or the last pin is arranged as the long pin.
[0018] In some embodiments, the pins on the corresponding two side edges of the frame body are respectively arranged in axial symmetry about a main axis of symmetry, the direction of the main axis of symmetry is consistent with the first direction, and coincides with one of the central axes of the frame body; or,
[0019] The pins on the corresponding two side edges of the frame body are respectively arranged in central symmetry about the center of the frame body.
[0020] In some embodiments, the lead frame further comprises an auxiliary connecting part arranged on the frame body, and two side ends of the auxiliary connecting part are connected with the edges of the frame body for auxiliary support of the chip.
[0021] In some embodiments, each of the pins has a body part for regular electrical connection of the chip;
[0022] Part of the pins are distinguished as the long pins by extending a preset length from the end of the body part to form an extension part connected with the body part; and the rest of the pins are distinguished as the short pins by not extending the body part.
[0023] The thickness of each of the extension parts is less than the thickness of the body part to adapt to the plastic package shape of the chip.
[0024] Another aspect of the present application also provides a packaged semiconductor, comprising:
[0025] the chip body;
[0026] any one of the lead frames, the pins in the lead frame are electrically connected with the chip body;
[0027] the plastic encapsulant, covering the chip body and at least part of the lead frame, for providing protection.
[0028] Compared with the prior art, the lead frame and the packaged semiconductor provided by the present application have the following beneficial effects: first, by extending part of the pins to the edge of the frame body to form long pins, in combination with the arrangement of long pins and short pins, diversified choices are provided for the connection of the chip, different connection modes can be selected according to chips of different sizes and layouts, thereby improving the versatility and applicability of the lead frame. Specifically, the present application provides additional space for the electrical connection of the chip, effectively prevents the collision of the ceramic nozzle and the chip in some bonding processes, reduces the operation risk, and improves the safety and reliability of the bonding process. Second, the design of the long pin can adapt to the circuit layout of different chips, so that the lead frame can adapt to variable chip designs, ensuring the rationality and effectiveness of the lead. BRIEF DESCRIPTION OF DRAWINGS
[0029] The above-mentioned features, technical characteristics, advantages and implementation modes of the present application will be further described in a clear and understandable manner in combination with the preferred embodiments and the accompanying drawings.
[0030] Figure 1 is a structural schematic diagram of the lead frame in an embodiment of the present application;
[0031] Figure 2 is a schematic diagram of the lead frame shown in Figure 1 when the chip is arranged on the lead frame;
[0032] Figure 3 is a structural schematic diagram of the lead frame in another embodiment of the present application;
[0033] Figure 4 is a sectional view of the packaged semiconductor in an embodiment of the present application.
[0034] Explanation of reference numerals: frame body 10; first edge 101; second edge 102; pin 20; body part 201; extension part 202; welding area 210; long pin 211; short pin 212; auxiliary connection part 30; chip body 40; plastic encapsulant 50. DETAILED DESCRIPTION
[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, specific implementations of the present application will be described below with reference to the drawings. Obviously, the drawings in the following description only represent some of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can also be obtained.
[0036] For the sake of simplicity of the drawings, only the parts related to the application are shown in each drawing, and they do not represent the actual structure of the product. In addition, in order to make the drawings simple and easy to understand, in some drawings, only one of the components with the same structure or function is shown schematically, or only one of them is marked. In this document, "one" not only means "only one", but also means "more than one" situation.
[0037] It should be further understood that the terms "and / or", "or" and other terms used in the present application and the appended claims refer to any combination of one or more of the associated listed items and all possible combinations, and include these combinations.
[0038] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.
[0039] In addition, in the description of the present application, the terms "first", "second" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.
[0040] Lead frame is a main structural material for semiconductor packaging. Lead frame is mainly composed of two parts: die paddle and lead finger. As a chip carrier of integrated circuit, lead frame makes the internal circuit lead-out end (bonding point) of the chip through the electrical connection of internal lead and external lead by means of bonding material (gold wire, aluminum wire, copper wire), forming an electrical circuit, and plays the role of bridge connecting the chip and external lead.
[0041] Generally speaking, the position of the lead corresponds to the circuit connection point of the chip, and when the chip is placed in the die bonding area (for example Figure 1After the shadow range shown), the circuit connection point can be directly welded on the corresponding pin. Taking a six-pin chip as an example, three circuit connection points are arranged on each side of the chip, and three pins are arranged on each side of the lead frame. When the chip is placed in the welding area and welded and fixed, the circuit connection points of the chip can be connected with the corresponding pins, and then the pins can be wired to realize the electrical connection between the chip and the external structure. However, when the size of the chip is large, the space is limited, and some pins may not be sufficient to meet the wiring needs, and the porcelain nozzle may collide with the chip during wiring, resulting in failure to complete the operation, for example Figure 2 As shown, a six-pin chip covers part of the area after being placed in the chip welding area, and the remaining area is used for wiring. Although the wiring areas corresponding to pins 1, 3, 4 and 6 are sufficient, the subsequent wiring operation can be normally performed, but the wiring area corresponding to pins 2 and 5 is blocked by the chip, which reduces the operation space. During subsequent wiring, the porcelain nozzle may collide with the chip during wiring, resulting in failure to normally complete the subsequent operation.
[0042] To optimize the prior art, with reference to the drawings attached Figure 1 and Figure 2 The lead frame provided by the present application comprises a frame body 10 and a plurality of pins 20. The pins 20 are arranged on the frame body 10, so that the plurality of pins 20 collectively form a welding area 210 for electrical connection of the chip.
[0043] Specifically, part of the pins 20 extend to the edge of the frame body 10 to form long pins 211, and the remaining pins 20 are short pins 212. The relative length of the long pins 211 is greater than that of the short pins 212, and the long pins 211 provide additional space for electrical connection of the chip.
[0044] The design of the long pins 211 is a significant feature of the present application. By extending the conventional pins to the edge of the frame body 10 to form longer pins, additional space is provided for electrical connection. On the one hand, the long pins 211 can provide more space, so that even if the size of the chip is large and the size of the welding area 210 is relatively fixed, the long pins 211 can ensure sufficient clearance, thereby reducing or avoiding collision between the porcelain nozzle and the chip during automatic welding. In particular, during automatic welding, the longer pins can reduce the risk of physical damage due to space limitations.
[0045] On the other hand, the circuit connection points on the chip can vary in design, and some can be concentrated in a specific area, and the provision of the long pin 211 provides greater flexibility, allowing the lead frame to adapt to the different layout of the circuit connection points, thereby optimizing the path of the electrical connection. Specifically, for different layouts of the circuit connection points on the chip, the provision of the long pin 211 can provide a more reasonable lead path, avoiding the crossing or unreasonable layout of the lead caused by the limitation of the short pin 212, thereby reducing the risk of short circuit and the rework caused by unreasonable lead layout, thereby improving the production efficiency.
[0046] In the present embodiment, the extension direction of the long pin 211 can be adjusted according to the layout of the chip and the packaging requirements. For example, the pin 20 can extend linearly to the edge of the frame body 10 to form the long pin 211, and the arrow on the long pin 211 in the drawing represents the corresponding extension direction. Of course, the pin 20 can also be bent and extended in other directions according to different space limitation conditions, so that the lead frame can adapt to complex packaging environments and reduce interference with other components.
[0047] In addition, the extension length of the long pin 211 can be customized according to the specific electrical connection requirements. In some applications that require more space to avoid contact or collision, the long pin 211 can be designed to be longer; and in the case of space limitation, the long pin 211 can be designed to be relatively short, but still provides more adjustment space than the short pin 212.
[0048] Based on the above, as shown in Figure 3 , all pins 20 include a body part 201 responsible for providing the regular electrical connection of the chip, some pins 20 only include the body part 201, and this part of the pin 20 is the short pin 212; some pins 20 extend a certain length from the end of the body part 201 to form an extension part 202, and this part of the pin 20 is the long pin 211, which is suitable for pins that require additional connection space or special layout requirements.
[0049] Importantly, as shown in Figure 4 , the thickness of the extension part 202 is designed to be thinner than the body part 201. First, by thinning the thickness of the extension part 202 of the long pin 211, the lead frame can maintain consistency with the plastic package shape of the chip and will not affect the appearance; second, thinning the thickness of the extension part 202 helps to avoid the phenomenon of copper exposure, thereby reducing the risk of short circuit of components and improving the reliability of the product.
[0050] In actual production, the thickness of the extension part 202 can be thinned by chemical etching or physical polishing, for example, the operator can select a suitable chemical etching solution according to the pin material, and can also speed up the etching speed by adjusting the concentration of the etching solution. After etching, cleaning and neutralization treatment is carried out to remove the residual chemical solution and ensure the quality of the pin surface.
[0051] In one embodiment, as shown in Figure 1 or Figure 3 , a plurality of pins 20 are arranged along the first direction on the opposite side edges of the frame body 10. Among them, the first direction is parallel to the extension direction of the central axis of the frame body 10, which helps to maintain consistency and symmetry between the pins, while providing more electrical connection points in a limited space.
[0052] In the manufacturing process, this pin arrangement can be realized by existing stamping or etching technology. The specific position, length (for example, long pin 211 or short pin 212) and number of pins 20 should be designed and optimized according to the electrical connection requirements and the specific specifications of the chip.
[0053] In one embodiment, the edges of the frame body 10 where the pins 20 start are not provided, including the first edge 101 and the second edge 102, which are oppositely arranged.
[0054] Based on the above, part of the pins 20 located on one side edge of the frame body 10 extend to the first edge 101, and part of the pins 20 on the other side edge extend to the second edge 102, so that the long pins 211 are formed on both sides of the frame body 10, for example Figure 1 , providing additional connection points and space to adapt to different connection and packaging requirements, while reducing interference between the pins 20 and improving the stability of signal transmission. On the contrary, as shown in Figure 3 , part of the pins 20 on different side edges of the frame body 10 extend to the first edge 101 or the second edge 102 at the same time, forming long pins 211 on the lead frame.
[0055] In this embodiment, the formation of the long pin 211 has two different implementation cases to adapt to different chip connection requirements and space layout. The former is that the pins 20 extend to different edges, so that the chip has extended connection space on both sides, which helps to realize more electrical connection points in space-limited packaging while maintaining appropriate spacing between the pins 20, reducing interference, and is suitable for applications that require pins 20 on both sides of the chip. The latter is that the pins 20 extend to the same edge, so that the additional connection space is concentrated on one side of the chip, which is suitable for chip designs that have more connection requirements on one side, while the other side can be kept simple to reduce space occupation.
[0056] It should be noted that in the present embodiment, the frame body 10 can be a quadrilateral or other specific geometric shape, wherein the first edge 101 and the second edge 102 are two opposite edges. In the quadrilateral frame body 10, in addition to the first edge 101 and the second edge 102, the other two edges are used to set the pins 20. In other embodiments, there can be a frame body 10 that is not a quadrilateral, and then there can be third, fourth, fifth, etc. edges, in which case the pins 20 can be set on these edges as needed and extend to some edges to form long pins 211.
[0057] Based on the above embodiment, at least one bending is performed in the process of extending the pin 20 to the first edge 101 or the second edge 102. Referring to the drawings, the extension direction of the pin 20 is changed by bending, and additional length is provided for the pin 20, so that it can adapt to different packaging requirements and space limitations.
[0058] Furthermore, the bent pin 20 is arranged in a staggered manner with other pins 20, in other words, each long pin 211 is offset in position relative to other pins 20 (short pins 212), thereby reducing the direct contact between the pins 20 and the potential risk of short circuit; at the same time, the staggered design optimizes the space between the pins 20, so that more pins 20 can be arranged in a limited space, thereby improving the connection density of the lead frame.
[0059] In one embodiment, the number of pins 20 is at least six, and at least three pins 20 are provided on the corresponding side edge of the frame body 10, thereby ensuring sufficient connection points for electrical connection.
[0060] It can be understood that the drawings specifically show six-pin and eight-pin configuration forms, but it should be pointed out that these are only a part of the many possible configurations, and for chips that require more connection points, the number of pins 20 can be increased accordingly.
[0061] Based on the above, in the present application, at least one long pin 211 is included in the pins 20 on the same edge of the frame body 10. Specifically, there are two cases, the first case: any pin 20 located between the first pin 20 and the last pin 20 is set as a long pin 211; the second case: the first pin 20 or the last pin 20 is set as a long pin 211.
[0062] It should be noted that the first case and the second case can exist in combination or independently, for example, the first case exists independently, and in the case of three pins 20 on one side, such as Figure 1As shown, the middle No. 2 pin and No. 5 pin are set as long pins 211, which provide additional connection space without increasing the total number of pins. Similarly, when the two cases are combined, as shown in FIG. 6, the No. 1 pin, No. 2 pin, No. 7 pin and No. 8 pin in the order direction are set as long pins 211, for example, in the case of four pins 20 on one side. Figure 3 As shown, for example, in the case of four pins 20 on one side, the No. 1 pin, No. 2 pin, No. 7 pin and No. 8 pin in the order direction are set as long pins 211.
[0063] In the present embodiment, based on the different positions and numbers of circuit connection points on the chip, the configuration of the long pins 211 on the frame body 10 can be changed accordingly. Specifically, the positions of the long pins 211 can be adjusted according to the specific layout of the circuit connection points on the chip, so that the long pins 211 can adapt to the case of needing additional connection space or needing to be connected to a special position, and the number of long pins 211 can also be adjusted according to the connection requirements to ensure that each circuit connection point can be properly electrically connected.
[0064] Specifically, in the design stage, the positions and numbers of long pins 211 are determined according to the layout of the circuit connection points on the chip, and the corresponding settings are made on the frame body 10, and then in the manufacturing process, the long pins 211 and short pins 212 are formed according to the design requirements.
[0065] Furthermore, two forms of symmetrical distribution of pins are provided in the present embodiment to adapt to different connection requirements.
[0066] One is an axial symmetry form, specifically, the pins 20 on the corresponding two side edges of the frame body 10 are distributed in axial symmetry about the main symmetry axis, the direction of the main symmetry axis coincides with the first direction, and coincides with one of the central axes of the frame body 10. This axial symmetry distribution form makes the pins 20 evenly distributed on the two side edges of the frame body 10, providing a symmetrical electrical connection path, which helps to reduce electrical interference and improve signal integrity.
[0067] Based on the above, the accompanying drawings Figure 3 As shown, four of the No. 3 pin, No. 4 pin, No. 5 pin and No. 6 pin are short pins 212, and the remaining four are long pins 211, and these pins 20 are distributed in axial symmetry about the main symmetry axis of the frame body 10. At this time, the long pins 211 are formed by extending the pins 20 to the same edge at the same time, and relatively, in other embodiments, they can also be extended to different edges respectively.
[0068] Another is a central symmetric form, specifically, the pins 20 on the corresponding two side edges of the frame body 10 are respectively centrally symmetric about the center of the frame body 10, which provides balanced electrical connection to some extent, especially in applications requiring balanced load on both sides of the chip, which helps to improve the symmetry and aesthetics of the package.
[0069] Based on the above, the present application Figure 1 A lead frame with six pins 20 is shown, in which two long pins 211 are located in the middle position, i.e. No. 2 pin, No. 5 pin, and the rest are four short pins 212 and located in the corner position. In this layout, the two long pins 211 are formed by extending the middle two pins 20 to different edges.
[0070] It should be noted that the display in the drawings is to intuitively explain the setting form of the pins 20, which helps to better understand the distribution and extension mode of the pins 20. In fact, the number of pins 20 in the present embodiment is not limited, and can be adjusted according to the specific packaging requirements and space layout.
[0071] In one embodiment, as Figure 3 shown, the lead frame enhances the support structure for the chip by introducing an auxiliary connecting part 30, improving stability and reliability. The auxiliary connecting part 30 is provided on the frame body 10, and its two side ends are connected with the edges of the frame body 10, which is used to assist the support of the chip, and ensures the stability of the position of the chip during packaging.
[0072] It can be understood that the design of the auxiliary connecting part 30 considers the integration with the frame body 10, and the connection of its two side ends with the edges of the frame body 10 ensures the coherence and stability of the overall structure. In the manufacturing process, the auxiliary connecting part 30 can be made of the same material as the frame body 10, and can be integrally formed with the frame body 10 by stamping or etching technology.
[0073] Further, the auxiliary connecting part 30 is located on the central axis of the frame body 10, which ensures that the force is more evenly distributed during the force process, reduces the structural deformation or damage caused by uneven force, and on the other hand, this arrangement also provides more uniform support, especially when the chip is subjected to external impact or temperature change, through uniform support reduces the risk of chip deviation or breakage, thereby improving the long-term reliability of the package.
[0074] In one embodiment, referring to the description attached Figure 4According to another aspect of the present application, the present application further provides a packaged semiconductor, comprising a chip body 40, the lead frame as above and a plastic encapsulant 50. The chip body 40 is electrically connected with the pins 20 in the lead frame, and the plastic encapsulant 50 covers the chip body 40 and at least part of the lead frame to provide protection.
[0075] The long pins 211 of the lead frame can provide sufficient connection space for the chip body 40 of larger size, improving the adaptability. Meanwhile, since the circuit connection points on the chip body 40 can have different layouts, the long pins 211 can be adjusted according to the specific positions of these connection points, providing more connection paths and ensuring the rationality of the connection of the chip body 40 relative to the lead frame.
[0076] In addition, in the present embodiment, the plastic encapsulant 50 can cover part of the lead frame, so that some of the pins 20 on the lead frame are exposed to realize the connection of the chip with external circuits. It can be understood that the design of the plastic encapsulant 50 needs to find a balance between protecting the chip and maintaining the connectivity of the pins 20, and covering part of the lead frame by the plastic encapsulant 50 can provide certain support and protection for the pins 20, but at the same time ensure the freedom of the exposed pins 20 to facilitate subsequent wire pulling and connection operations.
[0077] It should be noted that the above embodiments can be freely combined as needed. The above is only the preferred embodiment of the present application, and it should be noted that for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.
Claims
1. A leadframe, characterized by, Comprising: a frame body; a plurality of pins arranged on the frame body respectively to form a soldering area for electrical connection of a chip by the plurality of pins; in the plurality of pins, some pins extend to the edge of the frame body to form long pins, and the rest of the pins are short pins, the relative length of the long pins is greater than that of the short pins to provide additional space for electrical connection of the chip.
2. The lead frame according to claim 1, wherein the plurality of pins are arranged on opposite edges of the frame body respectively along a first direction, the first direction being parallel to the extension direction of one of the central axes of the frame body.
3. The lead frame according to claim 2, wherein the edge of the frame body on which the starting end of the pin is not arranged includes a first edge and a second edge, the first edge and the second edge being oppositely arranged; some pins on one side edge of the frame body extend to the first edge, and some pins on the other side edge of the frame body extend to the second edge to form the long pins on the lead frame; or some pins on different side edges of the frame body extend to the first edge or the second edge at the same time to form the long pins on the lead frame.
4. The lead frame according to claim 3, wherein the pins pass through at least one bending when extending to the first edge or the second edge, and are staggered with the rest of the pins to form the long pins.
5. The lead frame according to any one of claims 2-4, wherein the number of the pins is at least six, and at least three pins are arranged on the corresponding side edge of the frame body.
6. The lead frame according to claim 5, wherein in the pins on the same edge of the frame body, the number of the long pins is at least one; any pin between the first pin and the last pin is arranged as the long pin; and / or the first pin or the last pin is arranged as the long pin.
7. The lead frame according to claim 6, wherein the pins on the corresponding two side edges of the frame body are respectively distributed in axial symmetry about a main symmetry axis, the direction of the main symmetry axis being consistent with the first direction and coinciding with one of the central axes of the frame body; or the pins on the corresponding two side edges of the frame body are respectively distributed in central symmetry about the center of the frame body.
8. The leadframe of claim 1, wherein, Further comprising: an auxiliary connecting part arranged on the frame body, and two side ends of the auxiliary connecting part being connected with the edges of the frame body to assist in supporting the chip.
9. The lead frame according to any one of claims 1-4, 6-8, wherein each of the pins has a body part for regular electrical connection of the chip; wherein some of the pins form an extension part connected with the body part by extending a preset length from the end of the body part, and the some of the pins are distinguished as the long pins. The body part of the rest of the pins is not extended, and the rest of the pins are distinguished as the short pins; The thickness of each of the extension parts is less than the thickness of the body part, to adapt to the plastic package shape of the chip.
10. A packaged semiconductor, comprising: Comprise: A chip body; The lead frame as claimed in any one of claims 1-9, the pins in the lead frame being electrically connected with the chip body; A plastic package material, covering the chip body and at least part of the lead frame, for providing protection.